diff --git a/.changeset/clever-meals-vanish.md b/.changeset/clever-meals-vanish.md
new file mode 100644
index 0000000000..01f4c6d9bd
--- /dev/null
+++ b/.changeset/clever-meals-vanish.md
@@ -0,0 +1,5 @@
+---
+"react-email": patch
+---
+
+fix null byte characters being rendered in the preview server
diff --git a/packages/react-email/src/actions/render-email-by-path.tsx b/packages/react-email/src/actions/render-email-by-path.tsx
index e020917d71..11fa54da33 100644
--- a/packages/react-email/src/actions/render-email-by-path.tsx
+++ b/packages/react-email/src/actions/render-email-by-path.tsx
@@ -83,7 +83,10 @@ export const renderEmailByPath = async (
     });
 
     return {
-      markup,
+      // This ensures that no null byte character ends up in the rendered
+      // markup making users suspect of any issues. These null byte characters
+      // only seem to happen with React 18, as it has no similar incident with React 19.
+      markup: markup.replaceAll('\0', ''),
       plainText,
       reactMarkup,
     };
diff --git a/packages/render/src/node/read-stream.ts b/packages/render/src/node/read-stream.ts
index 8c24dcfe37..be7b04b412 100644
--- a/packages/render/src/node/read-stream.ts
+++ b/packages/render/src/node/read-stream.ts
@@ -29,10 +29,10 @@ export const readStream = async (
     });
     stream.pipe(writable);
 
-    return new Promise<string>((resolve, reject) => {
+    await new Promise<void>((resolve, reject) => {
       writable.on("error", reject);
       writable.on("close", () => {
-        resolve(result);
+        resolve();
       });
     });
   }