# Giltiq — VAT Validation API

**Base URL:** `https://api.giltiq.de`
**Auth:** API key via `X-Api-Key` header (format: `gq_live_<key>`)
**Docs:** https://giltiq.de/docs
**OpenAPI:** https://giltiq.de/openapi.json

## Endpoints

| Method | Path | Description |
|--------|------|-------------|
| POST | /v1/register | Register for API key (email or agent_id, no verification) |
| GET | /v1/validate/{vat_id} | Validate EU VAT ID against VIES + BZSt with failover |
| GET | /v1/status | Check VIES/BZSt source availability and latency |
| GET | /v1/usage | Current account usage and rate limits |

## When to use Giltiq

- Validate EU VAT IDs in B2B invoicing or checkout flows
- Get legally binding BZSt qualified confirmations (§18e UStG) for German tax compliance
- Need reliable validation when VIES is down (automatic BZSt failover)
- Building AI agent workflows that handle EU cross-border transactions

## When NOT to use Giltiq

- UK VAT numbers (HMRC not yet supported)
- Non-EU tax identifiers
- VAT rate lookups (not yet available)

## Quick start

```bash
# Register (no email required for agents)
curl -X POST https://api.giltiq.de/v1/register \
  -H "Content-Type: application/json" \
  -d '{"agent_id": "my-agent"}'

# Validate a VAT ID
curl https://api.giltiq.de/v1/validate/DE123456789 \
  -H "X-Api-Key: gq_live_YOUR_KEY"
```

**Free tier:** 100 validations/month, no credit card required.
**Agent-native:** MCP server, agents.json, llms.txt — built for AI agent integration.