Build & Deploy Errors

How to fix TypeScript CI failures, build errors, and deployment failures.

What Are Build Errors?

Build errors happen when your app works fine with pnpm dev but fails when you run pnpm build or when CI runs in your PR. This is the single most common issue for vibe coders.

Why? Because pnpm dev is lenient — it skips many checks to give you fast feedback. But pnpm build runs TypeScript in strict mode, which requires explicit type annotations.

The Most Common Error: Implicit 'any' Type

By far the most frequent build error. It looks like this:

./app/dashboard/page.tsx:24:30
Type error: Parameter 'item' implicitly has an 'any' type.

  22 |   const data = await fetchData();
  23 |   
> 24 |   const names = data.map((item) => item.name);
     |                              ^^^^
  25 |

The fix is simple — add a type annotation:

// BAD - Will fail in CI
const names = data.map((item) => item.name);

// GOOD - Explicit type annotation
const names = data.map((item: typeof data[0]) => item.name);

How to Read Build Output

The build output tells you exactly what is wrong:

./app/dashboard/page.tsx:24:30    <-- File and line number
Type error: Parameter 'item'     <-- What is wrong
  implicitly has an 'any' type.  <-- Why it is wrong

> 24 |   data.map((item) => ...    <-- The exact line

Key information:

1. File path — which file has the error
2. Line number — which line to look at
3. Error message — what needs to change

Always Run Build Before Committing

This is the most important habit for vibe coders:

# From the monorepo root
pnpm build:your-app-name

# If it passes, your commit will pass CI
# If it fails, fix the errors before committing

CI Check Failures in PRs

When you create a PR, CI automatically runs the build. If it fails:

1. The PR cannot be merged
2. You will see a red "X" next to the check
3. Click on "Details" to see the error output

Deploy Failures on Railway

Sometimes the build passes locally but the deploy fails on Railway. Common causes:

• Missing environment variables — set them in the Railway dashboard
• Different Node.js version — Railway may use a different version
• Missing dependencies — a package is not in package.json

Quiz