diff --git a/.changeset/fluffy-mayflies-switch.md b/.changeset/fluffy-mayflies-switch.md
new file mode 100644
index 000000000..41ac6a7d9
--- /dev/null
+++ b/.changeset/fluffy-mayflies-switch.md
@@ -0,0 +1,9 @@
+---
+'@cloudflare/next-on-pages': patch
+---
+
+suppress invalid env variables on `process.env` in the `next-dev` submodule
+
+improve `setupDevPlatform` so that it suppresses the environment variables (present
+in the edge runtime) that the Next.js dev server sets on `process.env` (such should not
+be used anyways since they won't be available in the preview nor in the deployed app)
diff --git a/internal-packages/next-dev/src/shared.ts b/internal-packages/next-dev/src/shared.ts
index 46c6b0ec4..192073ea1 100644
--- a/internal-packages/next-dev/src/shared.ts
+++ b/internal-packages/next-dev/src/shared.ts
@@ -60,6 +60,12 @@ function monkeyPatchProcessEnv(
 		!runtimeContext.process.env[processEnvIsPatched]
 	) {
 		if (runtimeContext.process.env) {
+			for (const key of Object.keys(runtimeContext.process.env)) {
+				if (!(key in env)) {
+					delete runtimeContext.process.env[key];
+				}
+			}
+
 			for (const [name, binding] of Object.entries(env)) {
 				runtimeContext.process.env[name] = binding;
 			}