# Show HN: Check – prefix any command to know if it'll work before you run it

> Source: <https://www.golproductions.com/check>
> Published: 2026-06-15 07:42:33+00:00

Prefix any command with `check`

and get one word back. The command is either runnable or it isn't. That's it.

Will this command produce a result? Check answers that question. Deterministically, at the speed of an API call, for four cents.

Pass any command. curl, wget, httpie, python, node — anything with a network target. From your terminal, a script, a pipeline, stdin, an AI agent — anywhere a command is generated before it's executed.

Runnable or invalid. Exit code 0 or 1. No scores, no explanations, no opinions. A fact, not an assessment.

Reads from arguments or stdin. Returns an exit code. Works in bash, CI, Docker, cron, webhook chains — anywhere `sh`

runs.

Check needs curl and a shell. You already have both.

`CHECK_KEY`

in your environment for CI and containers.Prepaid balance. No subscription. Never expires.

$0.04 deducted per check. Your balance stays until you use it.