# Domain Intelligence

> DNS records and email-policy presence in JSON. x402 v2 prototype. TESTNET ONLY; no real-money payments.

## API
- Base URL: https://api.x4-02.fr
- Health (free, GET): https://api.x4-02.fr/health
- Domain check (paid in test USDC, GET): https://api.x4-02.fr/v1/domain/check?domain=example.com
- OpenAPI (authoritative schema): https://api.x4-02.fr/openapi.json
- Interactive documentation: https://api.x4-02.fr/docs
- Informational service manifest: https://x4-02.fr/service.json
- Python client source: https://x4-02.fr/client.py
- Public repository and quickstart: https://github.com/Nicus83/domain-intelligence-client

## Payment flow
1. GET the domain check URL without payment. Expect HTTP 402.
2. Decode the PAYMENT-REQUIRED header using an x402 v2 SDK.
3. Validate the live challenge before signing: Base Sepolia eip155:84532, exact scheme, test USDC contract 0x036CbD53842c5426634e7929541eC2318f3dCF7e, amount 10000 atomic units (0.01 test USDC), recipient 0x68e1f3659A7DaeA2fee5FEf1f53C50cf013f6A56.
4. Only with explicit payment authorization, sign with a dedicated test wallet and send PAYMENT-SIGNATURE. Expect HTTP 200 and PAYMENT-RESPONSE.
5. Verify settlement. Do not automatically retry payments after errors. A reused authorization is rejected.

Never request a user's private key in chat or on this website. The Python client asks locally only with --pay; by default it reads the challenge without signing. Use a descriptive User-Agent. No API key required. No browser-based payment client is provided; browser CORS access is not claimed.

## Scope and limits
A, AAAA, MX, NS, CAA, TXT. SPF/DMARC presence only, not full validation. DMARC at the exact domain, no organizational fallback. DNS errors differ from absent records. No TLS, reputation or deliverability assessment. Cached results (up to 60 seconds, bounded by positive TTLs) are still paid per call.
Before payment: 60 requests/minute/IP, 16 active requests. After x402 validation: 30 requests/minute/IP, 8 concurrent analyses. Per-process memory limits reset on restart; shared public IPs share quotas.
The landing page includes a fictional, abbreviated response example. It does not execute analyses or initiate payments. This guide is not a live availability report.

## Human documentation
- English: https://x4-02.fr/
- Français: https://x4-02.fr/fr/
- Español: https://x4-02.fr/es/
- Deutsch: https://x4-02.fr/de/
- Português: https://x4-02.fr/pt/