diff --git a/src/api/converter.ts b/src/api/converter.ts
index b1ba92408..e5a1e1752 100644
--- a/src/api/converter.ts
+++ b/src/api/converter.ts
@@ -202,7 +202,10 @@ function toValueType(valueType: PrimitiveType): PbValueType {
     case PrimitiveType.Date:
       return PbValueType.DATE;
     default:
-      throw new YorkieError(Code.Unsupported, `unsupported type: ${valueType}`);
+      throw new YorkieError(
+        Code.ErrInvalidType,
+        `unsupported type: ${valueType}`,
+      );
   }
 }
 
@@ -216,7 +219,10 @@ function toCounterType(valueType: CounterType): PbValueType {
     case CounterType.LongCnt:
       return PbValueType.LONG_CNT;
     default:
-      throw new YorkieError(Code.Unsupported, `unsupported type: ${valueType}`);
+      throw new YorkieError(
+        Code.ErrInvalidType,
+        `unsupported type: ${valueType}`,
+      );
   }
 }
 
@@ -859,7 +865,7 @@ function fromPresenceChange<P extends Indexable>(
     };
   }
 
-  throw new YorkieError(Code.Unsupported, `unsupported type: ${type}`);
+  throw new YorkieError(Code.ErrInvalidType, `unsupported type: ${type}`);
 }
 
 /**
@@ -1476,7 +1482,7 @@ function bytesToSnapshot<P extends Indexable>(
  */
 function bytesToObject(bytes?: Uint8Array): CRDTObject {
   if (!bytes) {
-    throw new Error('bytes is empty');
+    throw new YorkieError(Code.ErrInvalidArgument, 'bytes is empty');
   }
 
   const pbElement = PbJSONElement.fromBinary(bytes);
@@ -1495,7 +1501,7 @@ function objectToBytes(obj: CRDTObject): Uint8Array {
  */
 function bytesToArray(bytes?: Uint8Array): CRDTArray {
   if (!bytes) {
-    throw new Error('bytes is empty');
+    throw new YorkieError(Code.ErrInvalidArgument, 'bytes is empty');
   }
 
   const pbElement = PbJSONElement.fromBinary(bytes);
@@ -1514,7 +1520,7 @@ function arrayToBytes(array: CRDTArray): Uint8Array {
  */
 function bytesToTree(bytes?: Uint8Array): CRDTTree {
   if (!bytes) {
-    throw new Error('bytes is empty');
+    throw new YorkieError(Code.ErrInvalidArgument, 'bytes is empty');
   }
 
   const pbElement = PbJSONElement.fromBinary(bytes);
diff --git a/src/document/crdt/element_rht.ts b/src/document/crdt/element_rht.ts
index d9d3bdadd..83700a549 100644
--- a/src/document/crdt/element_rht.ts
+++ b/src/document/crdt/element_rht.ts
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTElement } from '@yorkie-js-sdk/src/document/crdt/element';
+import { YorkieError, Code } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `ElementRHTNode` is a node of ElementRHT.
@@ -114,7 +114,10 @@ export class ElementRHT {
    */
   public delete(createdAt: TimeTicket, executedAt: TimeTicket): CRDTElement {
     if (!this.nodeMapByCreatedAt.has(createdAt.toIDString())) {
-      logger.fatal(`fail to find ${createdAt.toIDString()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${createdAt.toIDString()}`,
+      );
     }
 
     const node = this.nodeMapByCreatedAt.get(createdAt.toIDString())!;
@@ -142,8 +145,10 @@ export class ElementRHT {
       element.getCreatedAt().toIDString(),
     );
     if (!node) {
-      logger.fatal(`fail to find ${element.getCreatedAt().toIDString()}`);
-      return;
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${element.getCreatedAt().toIDString()}`,
+      );
     }
 
     const nodeByKey = this.nodeMapByKey.get(node.getStrKey());
diff --git a/src/document/crdt/rga_tree_list.ts b/src/document/crdt/rga_tree_list.ts
index df7bd0854..c4901baf0 100644
--- a/src/document/crdt/rga_tree_list.ts
+++ b/src/document/crdt/rga_tree_list.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { SplayNode, SplayTree } from '@yorkie-js-sdk/src/util/splay_tree';
 import {
   InitialTimeTicket,
@@ -22,6 +21,7 @@ import {
 } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTElement } from '@yorkie-js-sdk/src/document/crdt/element';
 import { Primitive } from '@yorkie-js-sdk/src/document/crdt/primitive';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `RGATreeListNode` is a node of RGATreeList.
@@ -180,7 +180,10 @@ export class RGATreeList {
   ): RGATreeListNode {
     let node = this.nodeMapByCreatedAt.get(createdAt.toIDString());
     if (!node) {
-      logger.fatal(`cant find the given node: ${createdAt.toIDString()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `cant find the given node: ${createdAt.toIDString()}`,
+      );
     }
 
     while (
@@ -232,12 +235,18 @@ export class RGATreeList {
   ): void {
     const prevNode = this.nodeMapByCreatedAt.get(prevCreatedAt.toIDString());
     if (!prevNode) {
-      logger.fatal(`cant find the given node: ${prevCreatedAt.toIDString()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `cant find the given node: ${prevCreatedAt.toIDString()}`,
+      );
     }
 
     const node = this.nodeMapByCreatedAt.get(createdAt.toIDString());
     if (!node) {
-      logger.fatal(`cant find the given node: ${createdAt.toIDString()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `cant find the given node: ${createdAt.toIDString()}`,
+      );
     }
 
     if (
@@ -284,7 +293,8 @@ export class RGATreeList {
       element.getCreatedAt().toIDString(),
     );
     if (!node) {
-      logger.fatal(
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
         `fail to find the given createdAt: ${element
           .getCreatedAt()
           .toIDString()}`,
diff --git a/src/document/crdt/rga_tree_split.ts b/src/document/crdt/rga_tree_split.ts
index 0d28d0895..45d8fd34d 100644
--- a/src/document/crdt/rga_tree_split.ts
+++ b/src/document/crdt/rga_tree_split.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { ActorID } from '@yorkie-js-sdk/src/document/time/actor_id';
 import { Comparator } from '@yorkie-js-sdk/src/util/comparator';
 import { SplayNode, SplayTree } from '@yorkie-js-sdk/src/util/splay_tree';
@@ -26,6 +25,7 @@ import {
   TimeTicketStruct,
 } from '@yorkie-js-sdk/src/document/time/ticket';
 import { GCChild, GCPair, GCParent } from '@yorkie-js-sdk/src/document/crdt/gc';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 export interface ValueChange<T> {
   actor: ActorID;
@@ -634,7 +634,8 @@ export class RGATreeSplit<T extends RGATreeSplitValue> implements GCParent {
       ? this.findFloorNodePreferToLeft(absoluteID)
       : this.findFloorNode(absoluteID);
     if (!node) {
-      logger.fatal(
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
         `the node of the given id should be found: ${absoluteID.toTestString()}`,
       );
     }
@@ -793,7 +794,8 @@ export class RGATreeSplit<T extends RGATreeSplitValue> implements GCParent {
   ): RGATreeSplitNode<T> {
     let node = this.findFloorNode(id);
     if (!node) {
-      logger.fatal(
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
         `the node of the given id should be found: ${id.toTestString()}`,
       );
     }
@@ -847,7 +849,10 @@ export class RGATreeSplit<T extends RGATreeSplitValue> implements GCParent {
     offset: number,
   ): RGATreeSplitNode<T> | undefined {
     if (offset > node.getContentLength()) {
-      logger.fatal('offset should be less than or equal to length');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `offset should be less than or equal to length`,
+      );
     }
 
     if (offset === 0) {
diff --git a/src/document/crdt/root.ts b/src/document/crdt/root.ts
index efe2305af..fe962f4b4 100644
--- a/src/document/crdt/root.ts
+++ b/src/document/crdt/root.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import {
   InitialTimeTicket,
   TimeTicket,
@@ -27,6 +26,7 @@ import { CRDTObject } from '@yorkie-js-sdk/src/document/crdt/object';
 import { GCPair } from '@yorkie-js-sdk/src/document/crdt/gc';
 import { CRDTText } from '@yorkie-js-sdk/src/document/crdt/text';
 import { CRDTTree } from '@yorkie-js-sdk/src/document/crdt/tree';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `CRDTElementPair` is a structure that represents a pair of element and its
@@ -134,7 +134,10 @@ export class CRDTRoot {
       const createdAt = pair.element.getCreatedAt();
       const subPath = pair.parent.subPathOf(createdAt);
       if (subPath === undefined) {
-        logger.fatal(`cant find the given element: ${createdAt.toIDString()}`);
+        throw new YorkieError(
+          Code.ErrInvalidArgument,
+          `cant find the given element: ${createdAt.toIDString()}`,
+        );
       }
 
       subPaths.unshift(subPath!);
diff --git a/src/document/crdt/tree.ts b/src/document/crdt/tree.ts
index 33624631f..7c5800205 100644
--- a/src/document/crdt/tree.ts
+++ b/src/document/crdt/tree.ts
@@ -43,6 +43,7 @@ import { Indexable } from '@yorkie-js-sdk/src/document/document';
 import type * as Devtools from '@yorkie-js-sdk/src/devtools/types';
 import { escapeString } from '@yorkie-js-sdk/src/document/json/strings';
 import { GCChild, GCPair, GCParent } from '@yorkie-js-sdk/src/document/crdt/gc';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `TreeNode` represents a node in the tree.
@@ -223,7 +224,8 @@ export class CRDTTreePos {
     const parentNode = tree.findFloorNode(parentID);
     let leftNode = tree.findFloorNode(leftSiblingID);
     if (!parentNode || !leftNode) {
-      throw new Error(
+      throw new YorkieError(
+        Code.ErrRefused,
         `cannot find node of CRDTTreePos(${parentID.toTestString()}, ${leftSiblingID.toTestString()})`,
       );
     }
@@ -514,7 +516,10 @@ export class CRDTTreeNode
    */
   get value() {
     if (!this.isText) {
-      throw new Error(`cannot get value of element node: ${this.type}`);
+      throw new YorkieError(
+        Code.ErrInvalidType,
+        `cannot get value of element node: ${this.type}`,
+      );
     }
 
     return this._value;
@@ -525,7 +530,10 @@ export class CRDTTreeNode
    */
   set value(v: string) {
     if (!this.isText) {
-      throw new Error(`cannot set value of element node: ${this.type}`);
+      throw new YorkieError(
+        Code.ErrInvalidType,
+        `cannot set value of element node: ${this.type}`,
+      );
     }
 
     this._value = v;
@@ -1217,7 +1225,10 @@ export class CRDTTree extends CRDTElement implements GCParent {
     ticket: TimeTicket,
   ): void {
     // TODO(hackerwins, easylogic): Implement this with keeping references of the nodes.
-    throw new Error(`not implemented: ${target}, ${source}, ${ticket}`);
+    throw new YorkieError(
+      Code.ErrUnimplemented,
+      `not implemented: ${target}, ${source}, ${ticket}`,
+    );
   }
 
   /**
diff --git a/src/document/document.ts b/src/document/document.ts
index 0ebf79ece..9343b6353 100644
--- a/src/document/document.ts
+++ b/src/document/document.ts
@@ -660,7 +660,7 @@ export class Document<T, P extends Indexable = Indexable> {
     } catch (err) {
       // drop clone because it is contaminated.
       this.clone = undefined;
-      logger.error(err);
+
       throw err;
     } finally {
       this.isUpdating = false;
@@ -847,7 +847,10 @@ export class Document<T, P extends Indexable = Indexable> {
   ): Unsubscribe {
     if (typeof arg1 === 'string') {
       if (typeof arg2 !== 'function') {
-        throw new Error('Second argument must be a callback function');
+        throw new YorkieError(
+          Code.ErrInvalidArgument,
+          'Second argument must be a callback function',
+        );
       }
       if (arg1 === 'presence') {
         const callback = arg2 as DocEventCallbackMap<P>['presence'];
@@ -1021,7 +1024,7 @@ export class Document<T, P extends Indexable = Indexable> {
         complete,
       );
     }
-    throw new Error(`"${arg1}" is not a valid`);
+    throw new YorkieError(Code.ErrInvalidArgument, `"${arg1}" is not a valid`);
   }
 
   /**
@@ -1761,11 +1764,17 @@ export class Document<T, P extends Indexable = Indexable> {
    */
   private undo(): void {
     if (this.isUpdating) {
-      throw new Error('Undo is not allowed during an update');
+      throw new YorkieError(
+        Code.ErrRefused,
+        'Undo is not allowed during an update',
+      );
     }
     const undoOps = this.internalHistory.popUndo();
     if (undoOps === undefined) {
-      throw new Error('There is no operation to be undone');
+      throw new YorkieError(
+        Code.ErrRefused,
+        'There is no operation to be undone',
+      );
     }
 
     this.ensureClone();
@@ -1855,12 +1864,18 @@ export class Document<T, P extends Indexable = Indexable> {
    */
   private redo(): void {
     if (this.isUpdating) {
-      throw new Error('Redo is not allowed during an update');
+      throw new YorkieError(
+        Code.ErrRefused,
+        'Redo is not allowed during an update',
+      );
     }
 
     const redoOps = this.internalHistory.popRedo();
     if (redoOps === undefined) {
-      throw new Error('There is no operation to be redone');
+      throw new YorkieError(
+        Code.ErrRefused,
+        'There is no operation to be redone',
+      );
     }
 
     this.ensureClone();
diff --git a/src/document/json/counter.ts b/src/document/json/counter.ts
index 6e1f9013a..fdffc975d 100644
--- a/src/document/json/counter.ts
+++ b/src/document/json/counter.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { ChangeContext } from '@yorkie-js-sdk/src/document/change/context';
 import { Primitive } from '@yorkie-js-sdk/src/document/crdt/primitive';
@@ -25,6 +24,7 @@ import {
   CRDTCounter,
 } from '@yorkie-js-sdk/src/document/crdt/counter';
 import type * as Devtools from '@yorkie-js-sdk/src/devtools/types';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `Counter` is a custom data type that is used to counter.
@@ -78,9 +78,10 @@ export class Counter {
    */
   public increase(v: number | Long): Counter {
     if (!this.context || !this.counter) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Counter is not initialized yet',
+      );
     }
 
     const ticket = this.context.issueTimeTicket();
@@ -105,7 +106,10 @@ export class Counter {
    */
   public toJSForTest(): Devtools.JSONElement {
     if (!this.context || !this.counter) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Counter is not initialized yet',
+      );
     }
 
     return this.counter.toJSForTest();
diff --git a/src/document/json/text.ts b/src/document/json/text.ts
index cebe776f8..28e8dba77 100644
--- a/src/document/json/text.ts
+++ b/src/document/json/text.ts
@@ -38,6 +38,7 @@ import { stringifyObjectValues } from '@yorkie-js-sdk/src/util/object';
 import type * as Devtools from '@yorkie-js-sdk/src/devtools/types';
 import { SplayTree } from '@yorkie-js-sdk/src/util/splay_tree';
 import { LLRBTree } from '@yorkie-js-sdk/src/util/llrb_tree';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `TextPosStruct` represents the structure of RGATreeSplitPos.
@@ -92,13 +93,17 @@ export class Text<A extends Indexable = Indexable> {
     attributes?: A,
   ): [number, number] | undefined {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     if (fromIdx > toIdx) {
-      logger.fatal('from should be less than or equal to to');
-      return;
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const range = this.text.indexRangeToPosRange(fromIdx, toIdx);
@@ -154,13 +159,17 @@ export class Text<A extends Indexable = Indexable> {
    */
   setStyle(fromIdx: number, toIdx: number, attributes: A): boolean {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      return false;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     if (fromIdx > toIdx) {
-      logger.fatal('from should be less than or equal to to');
-      return false;
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const range = this.text.indexRangeToPosRange(fromIdx, toIdx);
@@ -203,9 +212,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   indexRangeToPosRange(range: [number, number]): TextPosStructRange {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     const textRange = this.text.indexRangeToPosRange(range[0], range[1]);
@@ -217,9 +227,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   posRangeToIndexRange(range: TextPosStructRange): [number, number] {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     const textRange = this.text.findIndexesFromRange([
@@ -235,9 +246,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   toTestString(): string {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.toTestString();
@@ -248,9 +260,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   values(): Array<TextValueType<A>> {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.values();
@@ -285,8 +298,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   toString(): string {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      return '';
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.toString();
@@ -297,7 +312,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   public toJSON(): string {
     if (!this.context || !this.text) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.toJSON();
@@ -309,7 +327,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   public toJSForTest(): Devtools.JSONElement {
     if (!this.context || !this.text) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.toJSForTest();
@@ -321,9 +342,10 @@ export class Text<A extends Indexable = Indexable> {
    */
   createRangeForTest(fromIdx: number, toIdx: number): RGATreeSplitPosRange {
     if (!this.context || !this.text) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Text is not initialized yet',
+      );
     }
 
     return this.text.indexRangeToPosRange(fromIdx, toIdx);
diff --git a/src/document/json/tree.ts b/src/document/json/tree.ts
index 94c6ce06d..b99161875 100644
--- a/src/document/json/tree.ts
+++ b/src/document/json/tree.ts
@@ -32,7 +32,6 @@ import { TreeEditOperation } from '@yorkie-js-sdk/src/document/operation/tree_ed
 import { isEmpty, stringifyObjectValues } from '@yorkie-js-sdk/src/util/object';
 import { RHT } from '../crdt/rht';
 import { TreeStyleOperation } from '../operation/tree_style_operation';
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import type {
   ElementNode,
   TextNode,
@@ -43,6 +42,7 @@ import type {
   CRDTTreeNodeIDStruct,
 } from '@yorkie-js-sdk/src/document/crdt/tree';
 import type * as Devtools from '@yorkie-js-sdk/src/devtools/types';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * NOTE(hackerwins): In normal case, we should define the following types in
@@ -153,7 +153,10 @@ function createCRDTTreeNode(context: ChangeContext, content: TreeNode) {
  */
 function validateTextNode(textNode: TextNode): boolean {
   if (!textNode.value.length) {
-    throw new Error('text node cannot have empty value');
+    throw new YorkieError(
+      Code.ErrInvalidArgument,
+      'text node cannot have empty value',
+    );
   }
 
   return true;
@@ -172,7 +175,10 @@ function validateTreeNodes(treeNodes: Array<TreeNode>): boolean {
     for (const treeNode of treeNodes) {
       const { type } = treeNode;
       if (type !== DefaultTextType) {
-        throw new Error('element node and text node cannot be passed together');
+        throw new YorkieError(
+          Code.ErrInvalidArgument,
+          'element node and text node cannot be passed together',
+        );
       }
       validateTextNode(treeNode as TextNode);
     }
@@ -180,7 +186,10 @@ function validateTreeNodes(treeNodes: Array<TreeNode>): boolean {
     for (const treeNode of treeNodes) {
       const { type } = treeNode;
       if (type === DefaultTextType) {
-        throw new Error('element node and text node cannot be passed together');
+        throw new YorkieError(
+          Code.ErrInvalidArgument,
+          'element node and text node cannot be passed together',
+        );
       }
     }
   }
@@ -247,7 +256,10 @@ export class Tree {
    */
   public getSize(): number {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.getSize();
@@ -258,7 +270,10 @@ export class Tree {
    */
   public getNodeSize(): number {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.getNodeSize();
@@ -269,7 +284,10 @@ export class Tree {
    */
   public getIndexTree(): IndexTree<CRDTTreeNode> {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.getIndexTree();
@@ -280,11 +298,17 @@ export class Tree {
    */
   public styleByPath(path: Array<number>, attributes: { [key: string]: any }) {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     if (!path.length) {
-      throw new Error('path should not be empty');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'path should not be empty',
+      );
     }
     const [fromPos, toPos] = this.tree.pathToPosRange(path);
     const ticket = this.context.issueTimeTicket();
@@ -317,11 +341,17 @@ export class Tree {
     attributes: { [key: string]: any },
   ) {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     if (fromIdx > toIdx) {
-      throw new Error('from should be less than or equal to to');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const fromPos = this.tree.findPos(fromIdx);
@@ -360,11 +390,17 @@ export class Tree {
     attributesToRemove: Array<string>,
   ) {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     if (fromIdx > toIdx) {
-      throw new Error('from should be less than or equal to to');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const fromPos = this.tree.findPos(fromIdx);
@@ -470,13 +506,22 @@ export class Tree {
     splitLevel = 0,
   ): boolean {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
     if (fromPath.length !== toPath.length) {
-      throw new Error('path length should be equal');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'path length should be equal',
+      );
     }
     if (!fromPath.length || !toPath.length) {
-      throw new Error('path should not be empty');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'path should not be empty',
+      );
     }
 
     const fromPos = this.tree.pathToPos(fromPath);
@@ -500,13 +545,22 @@ export class Tree {
     splitLevel = 0,
   ): boolean {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
     if (fromPath.length !== toPath.length) {
-      throw new Error('path length should be equal');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'path length should be equal',
+      );
     }
     if (!fromPath.length || !toPath.length) {
-      throw new Error('path should not be empty');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'path should not be empty',
+      );
     }
 
     const fromPos = this.tree.pathToPos(fromPath);
@@ -525,10 +579,16 @@ export class Tree {
     splitLevel = 0,
   ): boolean {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
     if (fromIdx > toIdx) {
-      throw new Error('from should be less than or equal to to');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const fromPos = this.tree.findPos(fromIdx);
@@ -552,10 +612,16 @@ export class Tree {
     splitLevel = 0,
   ): boolean {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
     if (fromIdx > toIdx) {
-      throw new Error('from should be less than or equal to to');
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        'from should be less than or equal to to',
+      );
     }
 
     const fromPos = this.tree.findPos(fromIdx);
@@ -569,7 +635,10 @@ export class Tree {
    */
   public toXML(): string {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.toXML();
@@ -580,7 +649,10 @@ export class Tree {
    */
   public toJSON(): string {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.toJSON();
@@ -592,7 +664,10 @@ export class Tree {
    */
   public toJSForTest(): Devtools.JSONElement {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.toJSForTest();
@@ -605,7 +680,10 @@ export class Tree {
    */
   public toJSInfoForTest(): Devtools.TreeNodeInfo {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.toJSInfoForTest();
@@ -616,7 +694,10 @@ export class Tree {
    */
   public getRootTreeNode() {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.getRootTreeNode();
@@ -627,7 +708,10 @@ export class Tree {
    */
   public indexToPath(index: number): Array<number> {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.indexToPath(index);
@@ -638,7 +722,10 @@ export class Tree {
    */
   public pathToIndex(path: Array<number>): number {
     if (!this.context || !this.tree) {
-      throw new Error('it is not initialized yet');
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.pathToIndex(path);
@@ -651,9 +738,10 @@ export class Tree {
     range: [Array<number>, Array<number>],
   ): TreePosStructRange {
     if (!this.context || !this.tree) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     const indexRange: [number, number] = [
@@ -669,9 +757,10 @@ export class Tree {
    */
   indexRangeToPosRange(range: [number, number]): TreePosStructRange {
     if (!this.context || !this.tree) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     return this.tree.indexRangeToPosStructRange(range);
@@ -682,9 +771,10 @@ export class Tree {
    */
   posRangeToIndexRange(range: TreePosStructRange): [number, number] {
     if (!this.context || !this.tree) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     const posRange: [CRDTTreePos, CRDTTreePos] = [
@@ -702,9 +792,10 @@ export class Tree {
     range: TreePosStructRange,
   ): [Array<number>, Array<number>] {
     if (!this.context || !this.tree) {
-      logger.fatal('it is not initialized yet');
-      // @ts-ignore
-      return;
+      throw new YorkieError(
+        Code.ErrNotInitialized,
+        'Tree is not initialized yet',
+      );
     }
 
     const posRange: [CRDTTreePos, CRDTTreePos] = [
diff --git a/src/document/operation/add_operation.ts b/src/document/operation/add_operation.ts
index ec7208677..478f46c26 100644
--- a/src/document/operation/add_operation.ts
+++ b/src/document/operation/add_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTElement } from '@yorkie-js-sdk/src/document/crdt/element';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
@@ -23,6 +22,7 @@ import {
   Operation,
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `AddOperation` is an operation representing adding an element to an Array.
@@ -60,10 +60,16 @@ export class AddOperation extends Operation {
   public execute(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTArray)) {
-      logger.fatal(`fail to execute, only array can execute add`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only array can execute add`,
+      );
     }
     const array = parentObject as CRDTArray;
     const value = this.value.deepcopy();
diff --git a/src/document/operation/edit_operation.ts b/src/document/operation/edit_operation.ts
index 6175f9d77..290d6a819 100644
--- a/src/document/operation/edit_operation.ts
+++ b/src/document/operation/edit_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import { RGATreeSplitPos } from '@yorkie-js-sdk/src/document/crdt/rga_tree_split';
@@ -25,6 +24,7 @@ import {
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
 import { Indexable } from '../document';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `EditOperation` is an operation representing editing Text. Most of the same as
@@ -83,10 +83,16 @@ export class EditOperation extends Operation {
   public execute<A extends Indexable>(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTText)) {
-      logger.fatal(`fail to execute, only Text can execute edit`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only Text can execute edit`,
+      );
     }
 
     const text = parentObject as CRDTText<A>;
diff --git a/src/document/operation/increase_operation.ts b/src/document/operation/increase_operation.ts
index d606f271b..287087935 100644
--- a/src/document/operation/increase_operation.ts
+++ b/src/document/operation/increase_operation.ts
@@ -26,8 +26,8 @@ import {
   Primitive,
   PrimitiveType,
 } from '@yorkie-js-sdk/src/document/crdt/primitive';
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { CRDTCounter } from '@yorkie-js-sdk/src/document/crdt/counter';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `IncreaseOperation` represents an operation that increments a numeric value to Counter.
@@ -62,10 +62,16 @@ export class IncreaseOperation extends Operation {
   public execute(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTCounter)) {
-      logger.fatal(`fail to execute, only Counter can execute increase`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only Counter can execute increase`,
+      );
     }
     const counter = parentObject as CRDTCounter;
     const value = this.value.deepcopy() as Primitive;
diff --git a/src/document/operation/move_operation.ts b/src/document/operation/move_operation.ts
index 6a26b3e65..864d0372f 100644
--- a/src/document/operation/move_operation.ts
+++ b/src/document/operation/move_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import { CRDTArray } from '@yorkie-js-sdk/src/document/crdt/array';
@@ -22,6 +21,7 @@ import {
   Operation,
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `MoveOperation` is an operation representing moving an element to an Array.
@@ -64,10 +64,16 @@ export class MoveOperation extends Operation {
   public execute(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTArray)) {
-      logger.fatal(`fail to execute, only array can execute move`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only array can execute move`,
+      );
     }
     const array = parentObject as CRDTArray;
     const previousIndex = Number(array.subPathOf(this.createdAt));
diff --git a/src/document/operation/operation.ts b/src/document/operation/operation.ts
index bde2aca29..18057b00a 100644
--- a/src/document/operation/operation.ts
+++ b/src/document/operation/operation.ts
@@ -19,6 +19,7 @@ import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { TreeNode } from '@yorkie-js-sdk/src/document/crdt/tree';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import { Indexable } from '@yorkie-js-sdk/src/document/document';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `OpSource` represents the source of the operation. It is used to handle
@@ -210,7 +211,7 @@ export abstract class Operation {
     // it doesn't have an executedAt yet. The executedAt is set when
     // the operation is executed through undo or redo.
     if (!this.executedAt) {
-      throw new Error(`executedAt has not been set yet`);
+      throw new YorkieError(Code.ErrNotReady, 'executedAt is not set yet');
     }
     return this.executedAt;
   }
diff --git a/src/document/operation/remove_operation.ts b/src/document/operation/remove_operation.ts
index 5e88da410..f1ad7b453 100644
--- a/src/document/operation/remove_operation.ts
+++ b/src/document/operation/remove_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import {
@@ -30,6 +29,7 @@ import {
 import { CRDTObject } from '@yorkie-js-sdk/src/document/crdt/object';
 import { CRDTArray } from '@yorkie-js-sdk/src/document/crdt/array';
 import { SetOperation } from '@yorkie-js-sdk/src/document/operation/set_operation';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `RemoveOperation` is an operation that removes an element from `CRDTContainer`.
@@ -68,10 +68,16 @@ export class RemoveOperation extends Operation {
       this.getParentCreatedAt(),
     ) as CRDTContainer;
     if (!container) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(container instanceof CRDTContainer)) {
-      logger.fatal(`only object and array can execute remove: ${container}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `only object and array can execute remove: ${container}`,
+      );
     }
 
     // NOTE(chacha912): Handle cases where operation cannot be executed during undo and redo.
diff --git a/src/document/operation/set_operation.ts b/src/document/operation/set_operation.ts
index 8d01db463..ca30b6730 100644
--- a/src/document/operation/set_operation.ts
+++ b/src/document/operation/set_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTElement } from '@yorkie-js-sdk/src/document/crdt/element';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
@@ -25,6 +24,7 @@ import {
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
 import { RemoveOperation } from '@yorkie-js-sdk/src/document/operation/remove_operation';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `SetOperation` represents an operation that stores the value corresponding to the
@@ -66,10 +66,16 @@ export class SetOperation extends Operation {
   ): ExecutionResult | undefined {
     const obj = root.findByCreatedAt(this.getParentCreatedAt()) as CRDTObject;
     if (!obj) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(obj instanceof CRDTObject)) {
-      logger.fatal(`fail to execute, only object can execute set`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only object can execute set`,
+      );
     }
 
     // NOTE(chacha912): Handle cases where operation cannot be executed during undo and redo.
diff --git a/src/document/operation/style_operation.ts b/src/document/operation/style_operation.ts
index b0a248998..b7b4af721 100644
--- a/src/document/operation/style_operation.ts
+++ b/src/document/operation/style_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import { RGATreeSplitPos } from '@yorkie-js-sdk/src/document/crdt/rga_tree_split';
@@ -25,6 +24,7 @@ import {
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
 import { Indexable } from '../document';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  *  `StyleOperation` is an operation applies the style of the given range to Text.
@@ -77,10 +77,16 @@ export class StyleOperation extends Operation {
   public execute<A extends Indexable>(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTText)) {
-      logger.fatal(`fail to execute, only Text can execute edit`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only Text can execute edit`,
+      );
     }
     const text = parentObject as CRDTText<A>;
     const [, pairs, changes] = text.setStyle(
diff --git a/src/document/operation/tree_edit_operation.ts b/src/document/operation/tree_edit_operation.ts
index 6a2bb6f82..3557a765a 100644
--- a/src/document/operation/tree_edit_operation.ts
+++ b/src/document/operation/tree_edit_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import {
@@ -28,6 +27,7 @@ import {
   OperationInfo,
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `TreeEditOperation` is an operation representing Tree editing.
@@ -85,10 +85,16 @@ export class TreeEditOperation extends Operation {
   public execute(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTTree)) {
-      logger.fatal(`fail to execute, only Tree can execute edit`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only Tree can execute edit`,
+      );
     }
     const editedAt = this.getExecutedAt();
     const tree = parentObject as CRDTTree;
diff --git a/src/document/operation/tree_style_operation.ts b/src/document/operation/tree_style_operation.ts
index 5f16f92a4..ecaad81da 100644
--- a/src/document/operation/tree_style_operation.ts
+++ b/src/document/operation/tree_style_operation.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { TimeTicket } from '@yorkie-js-sdk/src/document/time/ticket';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import {
@@ -28,6 +27,7 @@ import {
   ExecutionResult,
 } from '@yorkie-js-sdk/src/document/operation/operation';
 import { GCPair } from '@yorkie-js-sdk/src/document/crdt/gc';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 /**
  * `TreeStyleOperation` represents an operation that modifies the style of the
@@ -107,10 +107,16 @@ export class TreeStyleOperation extends Operation {
   public execute(root: CRDTRoot): ExecutionResult {
     const parentObject = root.findByCreatedAt(this.getParentCreatedAt());
     if (!parentObject) {
-      logger.fatal(`fail to find ${this.getParentCreatedAt()}`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to find ${this.getParentCreatedAt()}`,
+      );
     }
     if (!(parentObject instanceof CRDTTree)) {
-      logger.fatal(`fail to execute, only Tree can execute edit`);
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
+        `fail to execute, only Tree can execute edit`,
+      );
     }
     const tree = parentObject as CRDTTree;
     let changes: Array<TreeChange>;
diff --git a/src/util/error.ts b/src/util/error.ts
index 981da64b5..3abd06324 100644
--- a/src/util/error.ts
+++ b/src/util/error.ts
@@ -27,8 +27,11 @@ export enum Code {
   // ErrUnimplemented is returned when the operation is not implemented.
   ErrUnimplemented = 'ErrUnimplemented',
 
-  // Unsupported is returned when the operation is not supported.
-  Unsupported = 'unsupported',
+  // ErrInvalidType is returned when the type is invalid.
+  ErrInvalidType = 'ErrInvalidType',
+
+  // ErrDummy is used to verify errors for testing purposes.
+  ErrDummy = 'ErrDummy',
 
   // ErrDocumentNotAttached is returned when the document is not attached.
   ErrDocumentNotAttached = 'ErrDocumentNotAttached',
@@ -44,6 +47,15 @@ export enum Code {
 
   // ErrInvalidArgument is returned when the argument is invalid.
   ErrInvalidArgument = 'ErrInvalidArgument',
+
+  // ErrNotInitialized is returned when required initialization has not been completed.
+  ErrNotInitialized = 'ErrNotInitialized',
+
+  // ErrNotReady is returned when execution of following actions is not ready.
+  ErrNotReady = 'ErrNotReady',
+
+  // ErrRefused is returned when the execution is rejected.
+  ErrRefused = 'ErrRefused',
 }
 
 /**
@@ -55,7 +67,6 @@ export class YorkieError extends Error {
 
   constructor(readonly code: Code, readonly message: string) {
     super(message);
-    this.toString = (): string =>
-      `${this.name}: [code=${this.code}]: ${this.message}`;
+    this.toString = (): string => `[code=${this.code}]: ${this.message}`;
   }
 }
diff --git a/src/util/index_tree.ts b/src/util/index_tree.ts
index 9f7c856dd..97c960615 100644
--- a/src/util/index_tree.ts
+++ b/src/util/index_tree.ts
@@ -15,6 +15,7 @@
  */
 
 import { TimeTicket } from '../yorkie';
+import { Code, YorkieError } from './error';
 
 /**
  * About `index`, `path`, `size` and `TreePos` in crdt.IndexTree.
@@ -129,7 +130,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
     this._children = children;
 
     if (this.isText && this._children.length > 0) {
-      throw new Error(`Text node cannot have children: ${this.type}`);
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
   }
 
@@ -303,7 +304,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   append(...newNode: Array<T>): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     this._children.push(...newNode);
@@ -319,7 +320,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   prepend(...newNode: Array<T>): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     this._children.unshift(...newNode);
@@ -333,12 +334,12 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   insertBefore(newNode: T, referenceNode: T): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     const offset = this._children.indexOf(referenceNode);
     if (offset === -1) {
-      throw new Error('child not found');
+      throw new YorkieError(Code.ErrInvalidArgument, 'child not found');
     }
 
     this.insertAtInternal(newNode, offset);
@@ -350,12 +351,12 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   insertAfter(newNode: T, referenceNode: T): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     const offset = this._children.indexOf(referenceNode);
     if (offset === -1) {
-      throw new Error('child not found');
+      throw new YorkieError(Code.ErrInvalidArgument, 'child not found');
     }
 
     this.insertAtInternal(newNode, offset + 1);
@@ -367,7 +368,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   insertAt(newNode: T, offset: number): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     this.insertAtInternal(newNode, offset);
@@ -379,12 +380,12 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   removeChild(child: T) {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     const offset = this._children.indexOf(child);
     if (offset === -1) {
-      throw new Error('child not found');
+      throw new YorkieError(Code.ErrInvalidArgument, 'child not found');
     }
 
     this._children.splice(offset, 1);
@@ -435,12 +436,12 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   insertAfterInternal(newNode: T, referenceNode: T): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     const offset = this._children.indexOf(referenceNode);
     if (offset === -1) {
-      throw new Error('child not found');
+      throw new YorkieError(Code.ErrInvalidArgument, 'child not found');
     }
 
     this.insertAtInternal(newNode, offset + 1);
@@ -452,7 +453,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   insertAtInternal(newNode: T, offset: number): void {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     this._children.splice(offset, 0, newNode);
@@ -465,7 +466,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   findOffset(node: T): number {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     if (node.isRemoved) {
@@ -489,7 +490,7 @@ export abstract class IndexTreeNode<T extends IndexTreeNode<T>> {
    */
   findBranchOffset(node: T): number {
     if (this.isText) {
-      throw new Error('Text node cannot have children');
+      throw new YorkieError(Code.ErrRefused, 'Text node cannot have children');
     }
 
     let current: T | undefined = node;
@@ -577,15 +578,24 @@ function tokensBetween<T extends IndexTreeNode<T>>(
   callback: (token: TreeToken<T>, ended: boolean) => void,
 ) {
   if (from > to) {
-    throw new Error(`from is greater than to: ${from} > ${to}`);
+    throw new YorkieError(
+      Code.ErrInvalidArgument,
+      `from is greater than to: ${from} > ${to}`,
+    );
   }
 
   if (from > root.size) {
-    throw new Error(`from is out of range: ${from} > ${root.size}`);
+    throw new YorkieError(
+      Code.ErrInvalidArgument,
+      `from is out of range: ${from} > ${root.size}`,
+    );
   }
 
   if (to > root.size) {
-    throw new Error(`to is out of range: ${to} > ${root.size}`);
+    throw new YorkieError(
+      Code.ErrInvalidArgument,
+      `to is out of range: ${to} > ${root.size}`,
+    );
   }
 
   if (from === to) {
@@ -663,7 +673,10 @@ function findTreePos<T extends IndexTreeNode<T>>(
   preferText = true,
 ): TreePos<T> {
   if (index > node.size) {
-    throw new Error(`index is out of range: ${index} > ${node.size}`);
+    throw new YorkieError(
+      Code.ErrInvalidArgument,
+      `index is out of range: ${index} > ${node.size}`,
+    );
   }
 
   if (node.isText) {
@@ -764,7 +777,7 @@ export function findLeftmost<T extends IndexTreeNode<T>>(node: T): T {
  */
 function findTextPos<T extends IndexTreeNode<T>>(node: T, pathElement: number) {
   if (node.size < pathElement) {
-    throw new Error('unacceptable path');
+    throw new YorkieError(Code.ErrInvalidArgument, 'unacceptable path');
   }
 
   for (let i = 0; i < node.children.length; i++) {
@@ -834,7 +847,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
     if (node.isText) {
       const offset = node.parent!.findOffset(node);
       if (offset === -1) {
-        throw new Error('invalid treePos');
+        throw new YorkieError(Code.ErrInvalidArgument, 'invalid treePos');
       }
 
       const sizeOfLeftSiblings = addSizeOfLeftSiblings(
@@ -858,7 +871,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
     while (node.parent) {
       const offset = node.parent.findOffset(node);
       if (offset === -1) {
-        throw new Error('invalid treePos');
+        throw new YorkieError(Code.ErrInvalidArgument, 'invalid treePos');
       }
 
       path.push(offset);
@@ -882,7 +895,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
    */
   public pathToTreePos(path: Array<number>): TreePos<T> {
     if (!path.length) {
-      throw new Error('unacceptable path');
+      throw new YorkieError(Code.ErrInvalidArgument, 'unacceptable path');
     }
 
     let node = this.root;
@@ -891,7 +904,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
       node = node.children[pathElement];
 
       if (!node) {
-        throw new Error('unacceptable path');
+        throw new YorkieError(Code.ErrInvalidArgument, 'unacceptable path');
       }
     }
 
@@ -900,7 +913,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
     }
 
     if (node.children.length < path[path.length - 1]) {
-      throw new Error('unacceptable path');
+      throw new YorkieError(Code.ErrInvalidArgument, 'unacceptable path');
     }
 
     return {
@@ -965,7 +978,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
       const parent = node.parent! as T;
       const offsetOfNode = parent.findOffset(node);
       if (offsetOfNode === -1) {
-        throw new Error('invalid pos');
+        throw new YorkieError(Code.ErrInvalidArgument, 'invalid pos');
       }
 
       size += addSizeOfLeftSiblings(parent, offsetOfNode);
@@ -979,7 +992,7 @@ export class IndexTree<T extends IndexTreeNode<T>> {
       const parent = node.parent;
       const offsetOfNode = parent.findOffset(node);
       if (offsetOfNode === -1) {
-        throw new Error('invalid pos');
+        throw new YorkieError(Code.ErrInvalidArgument, 'invalid pos');
       }
 
       size += addSizeOfLeftSiblings(parent, offsetOfNode);
diff --git a/src/util/logger.ts b/src/util/logger.ts
index fd33c5a56..15d2a9334 100644
--- a/src/util/logger.ts
+++ b/src/util/logger.ts
@@ -91,7 +91,7 @@ export const logger = {
     }
   },
 
-  fatal: (message: string, ...messages: Array<unknown>): void => {
+  fatal: (...messages: Array<unknown>): void => {
     if (typeof console != 'undefined') {
       if (typeof console.error !== 'undefined') {
         console.error('YORKIE F:', ...messages);
@@ -99,8 +99,6 @@ export const logger = {
         console.log('YORKIE F:', ...messages);
       }
     }
-
-    throw new Error(`YORKIE F: ${message}`);
   },
 
   isEnabled: (l: LogLevel): boolean => {
diff --git a/src/util/observable.ts b/src/util/observable.ts
index fc36ef15c..c80f1efb9 100644
--- a/src/util/observable.ts
+++ b/src/util/observable.ts
@@ -16,6 +16,7 @@
 
 import { logger } from '@yorkie-js-sdk/src/util/logger';
 import { uuid } from '@yorkie-js-sdk/src/util/uuid';
+import { Code, YorkieError } from './error';
 
 export type NextFn<T> = (value: T) => void;
 
@@ -106,11 +107,14 @@ class ObserverProxy<T> implements Observer<T> {
     let observer: Observer<T>;
 
     if (!nextOrObserver) {
-      logger.fatal('missing observer');
+      throw new YorkieError(Code.ErrInvalidArgument, 'missing observer');
     }
 
     if (this.finalized) {
-      logger.fatal('observable is finalized due to previous error');
+      throw new YorkieError(
+        Code.ErrRefused,
+        'observable is finalized due to previous error',
+      );
     }
 
     if (typeof nextOrObserver === 'object') {
diff --git a/src/util/splay_tree.ts b/src/util/splay_tree.ts
index 9dc0ce4b4..e10060494 100644
--- a/src/util/splay_tree.ts
+++ b/src/util/splay_tree.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { logger } from '@yorkie-js-sdk/src/util/logger';
+import { Code, YorkieError } from './error';
 
 /**
  * `SplayNode` is a node of SplayTree.
@@ -206,7 +206,8 @@ export class SplayTree<V> {
       }
     }
     if (pos > node.getLength()) {
-      logger.fatal(
+      throw new YorkieError(
+        Code.ErrInvalidArgument,
         `out of index range: pos: ${pos} > node.length: ${node.getLength()}`,
       );
     }
diff --git a/test/bench/tree.bench.ts b/test/bench/tree.bench.ts
index cec67a367..b8bb2f8ce 100644
--- a/test/bench/tree.bench.ts
+++ b/test/bench/tree.bench.ts
@@ -98,7 +98,7 @@ const benchmarkTreeConvert = (size: number) => {
 
     root.tree = new Tree({
       type: 'doc',
-      children: [{ type: 'p', children: children }],
+      children: [{ type: 'p', children }],
     });
   });
 
diff --git a/test/helper/helper.ts b/test/helper/helper.ts
index bb736b7a8..dbc6e6470 100644
--- a/test/helper/helper.ts
+++ b/test/helper/helper.ts
@@ -36,6 +36,7 @@ import { InitialChangeID } from '@yorkie-js-sdk/src/document/change/change_id';
 import { CRDTRoot } from '@yorkie-js-sdk/src/document/crdt/root';
 import { CRDTObject } from '@yorkie-js-sdk/src/document/crdt/object';
 import { ElementRHT } from '@yorkie-js-sdk/src/document/crdt/element_rht';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 export type Indexable = Record<string, any>;
 
@@ -66,9 +67,12 @@ export class EventCollector<E = string> {
             resolve();
           } else {
             reject(
-              new Error(`event is not equal ${count}-
-                expected: ${JSON.stringify(event)},
-                actual: ${JSON.stringify(this.events[count - 1])}`),
+              new YorkieError(
+                Code.ErrInvalidArgument,
+                `event is not equal  ${count}-
+              expected: ${JSON.stringify(event)},
+              actual: ${JSON.stringify(this.events[count - 1])}`,
+              ),
             );
           }
           return;
diff --git a/test/integration/client_test.ts b/test/integration/client_test.ts
index c56997f10..b315408f4 100644
--- a/test/integration/client_test.ts
+++ b/test/integration/client_test.ts
@@ -32,7 +32,7 @@ import {
   withTwoClientsAndDocuments,
 } from '@yorkie-js-sdk/test/integration/integration_helper';
 import { ConnectError, Code as ConnectCode } from '@connectrpc/connect';
-import { Code } from '@yorkie-js-sdk/src/util/error';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 describe.sequential('Client', function () {
   afterEach(() => {
@@ -133,7 +133,7 @@ describe.sequential('Client', function () {
       // Simulate network error with fetch
       vi.stubGlobal('fetch', () => {
         return Promise.resolve().then(() => {
-          throw new Error('Failed to fetch');
+          throw new YorkieError(Code.ErrDummy, 'Failed to fetch');
         });
       });
 
@@ -211,7 +211,7 @@ describe.sequential('Client', function () {
     // Simulate network error
     vi.stubGlobal('fetch', () => {
       return Promise.resolve().then(() => {
-        throw new Error('Failed to fetch');
+        throw new YorkieError(Code.ErrDummy, 'Failed to fetch');
       });
     });
 
diff --git a/test/integration/object_test.ts b/test/integration/object_test.ts
index c4b982367..b033e100e 100644
--- a/test/integration/object_test.ts
+++ b/test/integration/object_test.ts
@@ -8,7 +8,7 @@ import {
   testRPCAddr,
 } from '@yorkie-js-sdk/test/integration/integration_helper';
 import { toStringHistoryOp } from '@yorkie-js-sdk/test/helper/helper';
-import { YorkieError } from '@yorkie-js-sdk/src/util/error';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 describe('Object', function () {
   it('valid key test', function () {
@@ -63,7 +63,7 @@ describe('Object', function () {
     assert.throws(() => {
       doc.update((root) => {
         root['k2'].push('4');
-        throw new Error('dummy error');
+        throw new YorkieError(Code.ErrDummy, 'dummy error');
       }, 'push "4"');
     }, 'dummy error');
     assert.equal(
diff --git a/test/integration/primitive_test.ts b/test/integration/primitive_test.ts
index f102cb23f..c7bac18fd 100644
--- a/test/integration/primitive_test.ts
+++ b/test/integration/primitive_test.ts
@@ -3,6 +3,7 @@ import Long from 'long';
 import { Document } from '@yorkie-js-sdk/src/document/document';
 import { InitialCheckpoint } from '@yorkie-js-sdk/src/document/change/checkpoint';
 import { withTwoClientsAndDocuments } from '@yorkie-js-sdk/test/integration/integration_helper';
+import { Code, YorkieError } from '@yorkie-js-sdk/src/util/error';
 
 describe('Primitive', function () {
   it('should apply updates of string', function () {
@@ -35,10 +36,11 @@ describe('Primitive', function () {
     });
     assert.equal('{"k1":{"k1-1":1,"k1-2":2}}', doc.toSortedJSON());
     assert.throws(() => {
+      const errorMsg = 'dummy error';
       doc.update((root) => {
         delete root['k1']['k1-1'];
-        throw Error('dummy error');
-      }, 'dummy error');
+        throw new YorkieError(Code.ErrDummy, errorMsg);
+      }, errorMsg);
     });
     assert.equal('{"k1":{"k1-1":1,"k1-2":2}}', doc.toSortedJSON());
   });