Pay-per-call web scraping for AI agents with x402
Your agent needs one web page or one Google result set, not a monthly plan. With FastAF it can pay per call in USDC over x402, with no account and no API key. Prices start at $0.003 per call. Full spec: api.fastaf.co/openapi.json.
1. Ask for the data
Request the SERP endpoint without a payment header to obtain the live quote for this exact URL.
curl -i "https://api.fastaf.co/x402/v1/serp?query=best+running+shoes&country=us&language=en"2. Read the 402 quote
The first reply is 402 Payment Required. The PAYMENT-REQUIRED header quotes the fixed price for this endpoint (for example $0.003 for serp and amazon, $0.005 for scrape). Nothing has been charged yet.
3. Sign and retry the same URL
Sign the quote with an x402 v2 client and send the identical URL again with the PAYMENT-SIGNATURE header:
# PAYMENT_SIGNATURE must be created by a funded x402 v2 wallet client
# from the live challenge for this exact URL.
curl -i -H "PAYMENT-SIGNATURE: $PAYMENT_SIGNATURE" \
"https://api.fastaf.co/x402/v1/serp?query=best+running+shoes&country=us&language=en"Payment settles only on a successful result. Validation and failed data calls do not settle. HTTP 402 is a payment challenge. A settlement failure does not deliver a successful paid response. Never reuse a settled signature: concurrent or already consumed payment authorizations return 409. Do not blindly retry after an uncertain network outcome.
4. Options that cost more
Some options cost more than the fixed x402 price: SERP advance_search, and scrape with rendering plus premium proxies or AI extraction. Unsigned requests still receive a 402 challenge; signed requests with options outside the covered price band return 400 options_need_api_key before payment verification or settlement. Eligibility is checked against the calculated credit cost, not simply whether an option is called premium. Use an API key for those (free key at fastaf.co/signup: 500 free credits every month after email verification).
5. The MCP route
Prefer tools over raw HTTP? Point your MCP client at https://api.fastaf.co/mcp (Streamable HTTP). Its active tool catalog includes scrape_url, google_search and amazon_product. Listing the tools needs no key; tool calls need an API key or an OAuth token authorized using an existing FastAF key. MCP does not accept x402 payments.
{ "mcpServers": { "fastaf": { "url": "https://api.fastaf.co/mcp", "headers": { "Authorization": "Bearer YOUR_KEY" } } } }Endpoints at a glance
| Endpoint | Price |
|---|---|
| serp / search, amazon, reddit | $0.003 |
| scrape, screenshot, maps, news, scholar, jobs, linkedin jobs, bing, youtube, patents, flights, walmart, ebay, zillow, x | $0.005 |
| shopping, ai, google images | $0.010 |
| $0.060 |
Prices checked on 28 October 2026 against code and live unpaid 402 challenges for the published x402 routes: 3,000 atomic USDC = $0.003; 5,000 = $0.005; 10,000 = $0.01; 60,000 = $0.06. USDC has six decimals. The payment network is Base (eip155:8453). Read each live quote before signing. To see how agents discover these routes before paying, read the checklist for how agents find a paid x402 API.
FAQ
Is the first 402 response a charge?
No. It supplies payment requirements. A funded x402 client must validate and sign the live quote before retrying the identical request.
Can I pay for MCP calls with x402?
No. Use x402 REST routes for wallet payments. MCP calls require a FastAF key or OAuth authorization using an existing key.
Is there a free tier?
Accounts receive 500 free credits every month after email verification, shared across keys and REST/MCP; they reset to 500 at 00:00 UTC on the 1st of each month and do not carry over. Free credits do not apply to x402: wallet-only x402 calls are always paid per call.
Where can I explore the API?
Read the documentation and pricing, or try the browser tools. Relevant products include the Google SERP API, Amazon API and web scraping API. See Amazon price monitoring, page-to-Markdown workflows and the x402 glossary.
Reference
- FastAF documentation: every parameter and response field
- Docs: authentication, errors, MCP and x402
- Pricing: credit packs from $10, without expiry
Other sources
- How to read public Amazon data when your requests fail
- How to read public Google Search data when your requests fail
- How to read public Walmart data when your requests fail
- How to read LinkedIn data with an API
- How to read public eBay data when your requests fail
- How to read public Booking.com data when your requests fail
- How to read X profile data with an API
- How to read public Zillow data when your requests fail
- MCP servers for Amazon, SERP and web scraping
- Cost per agent: monthly SaaS vs x402 pay-per-call
- How FastAF handles heavy pages and timeouts
- x402 endpoint discovery checklist: how agents find a paid API (and how FastAF passes it)
- Add FastAF to Claude Code, Codex and Cursor
- How to detect poisoned or incomplete SERP results in AI agents
- Cap agent spend per call with fixed x402 prices
- Use FastAF from the Cloudflare Agents SDK
- FastAF as a fallback search provider
- Budget a scraping job before you run it
- Try FastAF for free, no card
- Too many MCP tools? Keep agent context small
- How agents find an API (and where FastAF is)
- Why agent retries cost more than you think
- All how-to guides