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](https://www.x402.org), with no account and no API key. Prices start at $0.003 per call. Full spec: [api.fastaf.co/openapi.json](https://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](https://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 linkedin $0.060 [Start at fastaf.co](https://fastaf.co) 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](/how-to/x402-discovery-checklist/). ## 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](/docs/) and [pricing](/pricing/), or try the [browser tools](/tools/). Relevant products include the [Google SERP API](/apis/google-serp-api/), [Amazon API](/apis/amazon-api/) and [web scraping API](/apis/web-scraping-api/). See [Amazon price monitoring](/use-cases/scrape-amazon-prices-ai-agent/), [page-to-Markdown workflows](/use-cases/web-page-to-markdown-for-llm/) and the [x402 glossary](/glossary/x402/). ## Reference * [FastAF documentation](/docs/): every parameter and response field * [Docs](/docs/): authentication, errors, MCP and [x402](/docs/#x402) * [Pricing](/pricing/): credit packs from $10, without expiry ## Other sources * [How to read public Amazon data when your requests fail](/how-to/read-amazon-data/) * [How to read public Google Search data when your requests fail](/how-to/read-google-data/) * [How to read public Walmart data when your requests fail](/how-to/read-walmart-data/) * [How to read LinkedIn data with an API](/how-to/read-linkedin-data/) * [How to read public eBay data when your requests fail](/how-to/read-ebay-data/) * [How to read public Booking.com data when your requests fail](/how-to/read-booking-data/) * [How to read X profile data with an API](/how-to/read-x-data/) * [How to read public Zillow data when your requests fail](/how-to/read-zillow-data/) * [MCP servers for Amazon, SERP and web scraping](/how-to/best-mcp-servers-amazon-serp-scraping/) * [Cost per agent: monthly SaaS vs x402 pay-per-call](/how-to/cost-per-agent-saas-vs-x402/) * [How FastAF handles heavy pages and timeouts](/how-to/heavy-pages-timeouts/) * [x402 endpoint discovery checklist: how agents find a paid API (and how FastAF passes it)](/how-to/x402-discovery-checklist/) * [Add FastAF to Claude Code, Codex and Cursor](/how-to/add-fastaf-claude-code-codex-cursor/) * [How to detect poisoned or incomplete SERP results in AI agents](/how-to/detect-poisoned-incomplete-serp-results/) * [Cap agent spend per call with fixed x402 prices](/how-to/agent-spend-caps-per-call-pricing/) * [Use FastAF from the Cloudflare Agents SDK](/how-to/fastaf-cloudflare-agents-sdk/) * [FastAF as a fallback search provider](/how-to/search-api-fallback-provider/) * [Budget a scraping job before you run it](/how-to/budget-scraping-job-fixed-prices/) * [Try FastAF for free, no card](/how-to/free-search-api-for-agents/) * [Too many MCP tools? Keep agent context small](/how-to/mcp-tool-schema-bloat/) * [How agents find an API (and where FastAF is)](/how-to/agent-discovery-files/) * [Why agent retries cost more than you think](/how-to/agent-tool-retry-cost/) * [All how-to guides](/how-to/) ## Compare * [FastAF vs SerpApi](/compare/serpapi/) * [FastAF vs Exa](/compare/exa/) * [FastAF vs Tavily](/compare/tavily/) * [FastAF vs Firecrawl](/compare/firecrawl/) * [FastAF vs Apify](/compare/apify/) * [FastAF vs toll402](/compare/toll402/) * [FastAF vs serp402](/compare/serp402/) * [FastAF vs AgentBIT](/compare/agentbit/) * [FastAF vs Amazon PA-API](/compare/amazon-pa-api/) * [FastAF vs Serper](/compare/serper/) * [FastAF vs ScrapingBee](/compare/scrapingbee/) * [FastAF vs ScraperAPI](/vs/scraperapi/) * [FastAF vs Bright Data](/vs/bright-data/) * [Benchmarks](/benchmarks/): latency and cost per 1,000 requests, measured ## Try it on your own request 500 free credits every month after email verification, no card. [Start free](/signup/)[FastAF documentation](/docs/) ## Related * [x402](/glossary/x402/) * [Free x402 Endpoint Tester](/tools/x402-endpoint-tester/) * [How to read public Amazon data when your requests fail](/how-to/read-amazon-data/)