CI "prettier: command not found" - Fix Missing Prettier Binary

By Daniel Zoghalchali·Latchkey

The shell could not find a prettier executable. Prettier is not installed in the project, dev dependencies were pruned, or the step invoked a bare prettier that only resolves to a global install CI does not have.

What this error means

The format step fails with prettier: command not found and exit code 127. The same command works locally where Prettier is on PATH or installed.

$ prettier --check .
/bin/sh: 1: prettier: command not found
Error: Process completed with exit code 127.

Common causes

Prettier not installed or dev deps pruned

Prettier is missing from devDependencies, or the install ran with --omit=dev/--production, so the binary is absent in CI.

Calling a bare global prettier

The step runs prettier directly, relying on a global install. CI has no global Prettier, so it must use the local binary via npx/an npm script.

How to fix it

Install Prettier and call it locally

Add Prettier as a dev dependency and invoke the project-local binary.

npm install -D prettier
npx prettier --check .   # or: npm run format:check

Keep dev dependencies for the format step

1. Do not pass --omit=dev/--production to the install before formatting.
2. Define a "format:check": "prettier --check ." npm script.
3. Use npm ci (with dev deps) so the binary is present.

How to prevent it

• Declare Prettier in devDependencies and run it via an npm script or npx.
• Keep dev dependencies installed for the format step in CI.
• Never rely on a global Prettier install in CI.

Frequently asked questions

Related guides

References

• Node.js documentation
• npm CLI documentation
• GitHub Actions documentation