diff --git a/packages/backend/src/routes/repos.ts b/packages/backend/src/routes/repos.ts
index f2e38af..701fa52 100644
--- a/packages/backend/src/routes/repos.ts
+++ b/packages/backend/src/routes/repos.ts
@@ -9,6 +9,7 @@ import {
   commitFiles,
   push,
   getDiff,
+  validateCommitMessage,
 } from "../services/git.service.js";
 import type { RepoName } from "../config/repos.js";
 
@@ -88,6 +89,12 @@ router.post("/:repo/commit", async (req, res) => {
     if (body) fullMessage += `\n\n${body}`;
     if (issueRef) fullMessage += `\n\nFixes #${issueRef}`;
 
+    const validation = validateCommitMessage(fullMessage);
+    if (!validation.valid) {
+      res.status(400).json({ error: validation.error });
+      return;
+    }
+
     const repoPath = getRepoPath(repoName);
     const result = await commitFiles(repoPath, fullMessage, files);
     res.json(result);
diff --git a/packages/backend/src/services/git.service.ts b/packages/backend/src/services/git.service.ts
index fb505bf..0a50944 100644
--- a/packages/backend/src/services/git.service.ts
+++ b/packages/backend/src/services/git.service.ts
@@ -52,7 +52,25 @@ export async function pull(repoPath: string) {
   return g.pull();
 }
 
+const COMMIT_PATTERN = /^(feat|fix|refactor|docs|chore|test|style|perf|ci|build|revert)(\(.+\))?: .{1,100}$/;
+
+export function validateCommitMessage(message: string): { valid: boolean; error?: string } {
+  const firstLine = message.split("\n")[0];
+  if (!COMMIT_PATTERN.test(firstLine)) {
+    return {
+      valid: false,
+      error: `Invalid format. Expected: type(scope): description. Valid types: feat, fix, refactor, docs, chore, test, style, perf, ci, build, revert`,
+    };
+  }
+  return { valid: true };
+}
+
 export async function commitFiles(repoPath: string, message: string, files?: string[]) {
+  const validation = validateCommitMessage(message);
+  if (!validation.valid) {
+    throw new Error(validation.error);
+  }
+
   const g = git(repoPath);
   if (files && files.length > 0) {
     await g.add(files);