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bzst_unavailable

BZSt is temporarily unreachable or returned a degradation status (evatr-0011, evatr-1001 through evatr-1004).

HTTP 503 · Service Unavailable

Example response

{
  "error": {
    "code": "bzst_unavailable",
    "message": "BZSt evatr-1001: service temporarily unavailable.",
    "retryable": true
  },
  "meta": {
    "request_id": "a1b2c3d4-...",
    "latency_ms": 4200,
    "bzst_status_code": "1001"
  }
}

What happened

The BZSt eVatR service returned a degradation status code: 0011 (general unavailability), or one of 1001 through 1004 (various maintenance and overload states). The request reached vatverify correctly and was forwarded to BZSt, but BZSt could not fulfil it. This is distinct from bzst_server_error, where BZSt accepted the request but failed internally.

BZSt schedules maintenance windows, particularly outside German business hours. During these windows the eVatR endpoint returns unavailability codes rather than timing out.

How to fix

  1. Retry with exponential backoff. A starting interval of 30 seconds is appropriate for most maintenance windows.
  2. Check /status for the current BZSt registry health before assuming a persistent outage.
  3. If your workflow is time-sensitive and BZSt is down, fall back to a plain VIES check via /v1/validate. A VIES check confirms the VAT number is currently registered but does not produce the qualified BZSt confirmation required by §18e UStG.
  4. If bzst_unavailable persists beyond 30 minutes, check the status page and consider queueing the confirmation for retry once the registry recovers.

Related errors

See also