# Testing

Use deterministic Test-account values to exercise validation, registry checks and webhooks.

Every Live account has an isolated Test account with separate API keys, resources and events. Test accepts the same requests as Live, but it does not contact external tax authorities. Use the values below to make asynchronous results deterministic without adding test-only parameters to your integration.

Test values have special behavior only in a Test account. Do not use them in Live: FiscalRail treats them as ordinary identifiers there and external registries may reject them.

## Test Tax IDs

Tax IDs have two distinct failure points:

| What you send | API result | Tax ID verification | Event |
| --- | --- | --- | --- |
| Invalid local format | Customer request returns `422 invalid_customer` | No Tax ID or verification is created | None |
| Valid format and valid registry sentinel | Customer request returns `201` | Moves from `pending` to `completed` with `valid: true` | `tax_id.verification.completed` |
| Valid format and invalid registry sentinel | Customer request returns `201` | Moves from `pending` to `completed` with `valid: false` | `tax_id.verification.completed` |

An invalid registry result is not an operational failure. `tax_id.verification.failed` is reserved for a registry request that cannot be completed after retries.

### EU VAT (`eu_vat`)

For every supported EU country other than Spain, combine the VIES prefix with one of these suffixes:

| Outcome | Value |
| --- | --- |
| Valid format; VIES `valid: true` | `<prefix>000000000` |
| Valid format; VIES `valid: false` | `<prefix>000000001` |
| Rejected immediately for invalid format | `<prefix>!` |

Usually the prefix is the same as `country`: for example, use `country: "PT"` with `PT000000000` or `PT000000001`. Greece is the exception: use `country: "GR"` with the `EL` prefix, such as `EL000000001`.

Spain applies NIF checksum rules before VIES verification, so use the values in [Testing the Spain regime](/en/tax-regimes/spain/testing).

### Local identifiers (`local`)

Local identifiers are never checked against a registry. In any country, `TEST-VALID` passes the basic format check and `INVALID VALUE!` is rejected immediately. There is no valid-versus-invalid registry sentinel for this type.

## Exercise webhooks

Create the customer in your Test account, retain the returned Tax ID ID, and subscribe a Test event destination to `tax_id.verification.completed`. Verification is asynchronous: the create response normally contains `verification.status: "pending"`; retrieve `/v1/tax_ids/{id}` or consume the event to observe the terminal value.

Tax-regime-specific validation and downstream outcomes live in the relevant testing guide:

- [Testing the Spain regime](/en/tax-regimes/spain/testing): Spanish NIFs, synchronous invoice validation, VERI*FACTU outcomes and their webhooks.

See [Receiving events with webhooks](/en/webhooks) for signature verification, retries and deduplication.