diff --git a/client.go b/client.go
index e036a4e..52b1b94 100644
--- a/client.go
+++ b/client.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
@@ -72,7 +71,7 @@ func (c *Castle) Filter(ctx context.Context, req *Request) (RecommendedAction, e
 	if req.Context == nil {
 		return RecommendedActionNone, errors.New("request.Context cannot be nil")
 	}
-	user_params := UserParams{
+	params := Params{
 		Email:    req.User.Email,
 		Username: req.User.Name,
 	}
@@ -81,10 +80,10 @@ func (c *Castle) Filter(ctx context.Context, req *Request) (RecommendedAction, e
 		Name:         req.Event.Name,
 		Status:       req.Event.EventStatus,
 		RequestToken: req.Context.RequestToken,
-		Params:       user_params,
+		Params:       params,
 		Context:      req.Context,
 		Properties:   req.Properties,
-		CreatedAt:    time.Now(),
+		CreatedAt:    req.CreatedAt,
 	}
 	return c.sendCall(ctx, r, FilterEndpoint)
 }
@@ -106,7 +105,7 @@ func (c *Castle) Risk(ctx context.Context, req *Request) (RecommendedAction, err
 		User:         req.User,
 		Context:      req.Context,
 		Properties:   req.Properties,
-		CreatedAt:    time.Now(),
+		CreatedAt:    req.CreatedAt,
 	}
 	return c.sendCall(ctx, r, RiskEndpoint)
 }
@@ -127,9 +126,7 @@ func (c *Castle) sendCall(ctx context.Context, r castleAPIRequest, url string) (
 	b := new(bytes.Buffer)
 
 	switch request := r.(type) {
-	case *castleRiskAPIRequest:
-		err = json.NewEncoder(b).Encode(request)
-	case *castleFilterAPIRequest:
+	case *castleFilterAPIRequest, *castleRiskAPIRequest:
 		err = json.NewEncoder(b).Encode(request)
 	}
 	if err != nil {
diff --git a/client_test.go b/client_test.go
index 9154bdc..e32dfaa 100644
--- a/client_test.go
+++ b/client_test.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -36,6 +37,7 @@ func configureRequest(httpReq *http.Request) *castle.Request {
 			Traits: map[string]string{"trait1": "traitValue1"},
 		},
 		Properties: map[string]string{"prop1": "propValue1"},
+		CreatedAt:  time.Now(),
 	}
 }
 
@@ -151,7 +153,7 @@ func TestCastle_Filter(t *testing.T) {
 				Type         castle.EventType   `json:"type"`
 				Status       castle.EventStatus `json:"status"`
 				RequestToken string             `json:"request_token"`
-				Params       castle.UserParams  `json:"params"`
+				Params       castle.Params      `json:"params"`
 				Context      *castle.Context    `json:"context"`
 				Properties   map[string]string  `json:"properties"`
 			}
diff --git a/model.go b/model.go
index 6fdafed..962ca14 100644
--- a/model.go
+++ b/model.go
@@ -52,6 +52,7 @@ type Request struct {
 	Event      Event
 	User       User
 	Properties map[string]string
+	CreatedAt  time.Time
 }
 
 // Context captures data from HTTP request.
@@ -70,7 +71,7 @@ type User struct {
 	Traits       map[string]string `json:"traits,omitempty"`
 }
 
-type UserParams struct {
+type Params struct {
 	Email    string `json:"email,omitempty"`
 	Phone    string `json:"phone,omitempty"`
 	Username string `json:"username,omitempty"`
@@ -85,7 +86,7 @@ type castleFilterAPIRequest struct {
 	Name         string            `json:"name,omitempty"`
 	Status       EventStatus       `json:"status"`
 	RequestToken string            `json:"request_token"`
-	Params       UserParams        `json:"params"`
+	Params       Params            `json:"params"`
 	Context      *Context          `json:"context"`
 	Properties   map[string]string `json:"properties,omitempty"`
 	CreatedAt    time.Time         `json:"created_at"`