## TL;DR

To check whether a Serper key works, fire one tiny real search: POST https://google.serper.dev/search with X-API-KEY set and body {"q": "test", "num": 1}. A 200 with an organic array means the key is good.

## Fix

1. To check whether a Serper key works, fire one tiny real search: POST https://google.serper.dev/search with X-API-KEY set and body {"q": "test", "num": 1}.
   Expected: You see the expected output instead of the problem.

## When to use

- You are dealing with this situation.
- The symptom matches: Serper has no account-probe endpoint; validate keys with a minimal search.

## When NOT to use

- Unrelated issues with a different cause.
- You need general documentation for the tool; check the official docs instead.

## Compatibility

Reported per the linked source.

## Variant phrasings

### Serper has no account-probe endpoint; validate keys with a minimal search

## Why it happens

Web (stackos api-keys.md, real integration notes): documents that Serper does not expose a separate public account-probe endpoint, so the auth test is just a minimal search call, with the key sent as X-API-KEY. Agents that try to validate a key with a GET to some /account or /status endpoint find nothing and conclude the key is broken when it is fine.

## Edge cases

- If your error message differs even slightly, this is probably a different issue; search the exact text.
- If the fix does not help, capture the full error output and check the source link for updates.