# NIF validation in sandbox answers with simulated data

With a test key, `POST /v1/nif/validate` checks the syntax only and no longer queries the AEAT register.

Oct 19, 2026 · Improved

In sandbox the NIF validation endpoint no longer queries the AEAT register. A well-formed NIF comes back `VALID` with the `legal_name` you sent, `legal_name_verified: false` and no `census_status`; a malformed one still comes back `INVALID`. With a Live key nothing changes.

## Endpoints

- `POST /v1/nif/validate` — Simulated in sandbox (test keys and the MCP server connected to Test)

## Where to go next

- [NIF validation is simulated](/verifactu/testing-in-sandbox#nif-validation-is-simulated)
- [Validate a NIF](/nif-validation/validateNif)

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