# Ontario Protocol x402 API Finder > Ontario Protocol x402 API Finder is a paid API for AI agents from ontarioprotocol.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-30). Finds up to 5 live x402-compatible paid APIs ranked by task fit, price, and repeat buyers for any given agent task description ## Facts - Endpoint: POST https://ontarioprotocol.com/api/x402/find-api?utm_source=zero.xyz - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-10-30 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/ontario-protocol-x402-api-finder-07449a0d - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SCUqY61hWLhbBS_NlXUa6 Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability ontario-protocol-x402-api-finder-07449a0d -d '' ``` Example prompt: Find me up to 3 live x402 APIs I can call to do web search for an AI agent, with a max price of $0.01 USDC per call. ## When to prefer this Use this endpoint when an AI agent needs to dynamically discover which x402-compatible paid API to call for a given task at runtime, rather than hardcoding a specific API. Ideal for agents that need to adapt their tool choices based on live availability, price, and task fit. Prefer this over static API directories when you need confirmation that the API is actually live and returning valid Base USDC 402 challenges right now. ## Known failure modes - No live match found for the task — no charge is applied and count returns 0 - Task string too short (under 3 chars) or too long (over 160 chars) — validation error - All candidate APIs failed live probe (unreachable or no valid 402 challenge) — empty results - max_usdc filter too restrictive — all candidates exceed price ceiling, empty results - Index stale or unavailable — fallback to live Bazaar/Agentic Market search, may increase latency - Provider's own 402 payment for the finder call fails — request not processed ## How this service works Which x402 API should my agent call? Live API finder for any task. Required: task. Returns up to 5 paid APIs that answered a fresh unpaid probe with a valid Base USDC 402, ranked by task fit, price and Bazaar-reported repeat buyers, each with live price, network and a ready-to-call request. Provider calls are paid separately. No live match, no charge. $0.005 USDC on Base. No account, no API key. Recommendations, not a safety guarantee. By Ontario Protocol. ## Output A JSON object containing a ranked list of up to 5 live x402 APIs, each with: endpoint URL, HTTP method, live-probed price in USDC, payment address, network (Base), rank score, human-readable description, and a ready-to-call request payload. Also includes funnel statistics (candidates found, probed, ranked, skipped, discarded) and metadata about the index used. ## Request schema (JSON Schema) ```json { "type": "object", "properties": { "task": { "type": "string", "maxLength": 160, "minLength": 3, "description": "Public task text; never credentials or private data." }, "limit": { "type": "integer", "default": 3, "maximum": 5, "minimum": 1 }, "max_usdc": { "type": "string", "description": "Optional per-call USDC price ceiling for returned APIs." } } } ``` ## Response schema (JSON Schema) ```json { "example": { "task": "web search for an AI agent", "count": 1, "funnel": { "live": 1, "probed": 4, "ranked": 7, "skipped": { "write_route": 1, "host_probe_cap": 3, "opted_out_host": 0, "endpoint_template": 2, "ontario_first_party": 0 }, "discarded": { "unreachable": 1, "no_payment_challenge": 2 }, "marketplace_candidates": 12 }, "method": "Candidates come from Ontario's copy of the Coinbase CDP Bazaar catalog (Base USDC listings settled in the last 30 days; index_as_of gives its age). When that copy is missing, older than 12 hours or has too few matches, live Coinbase CDP Bazaar, Agentic Market and Ontario ready-catalog searches are used. Candidates are ranked by task fit, price and repeat buyers (calls beyond unique payers), then probed unpaid: at most 2 per host, 3 s connect and read timeouts, observations reused up to 10 minutes. Write and money-moving routes and hosts that opted out are skipped, not probed. Only valid Base USDC x402 challenges within budget are returned. Ontario's own paid routes are excluded.", "schema": "ontario.x402_api_finder.v1", "status": "ok", "filters": { "asset": "USDC", "limit": 3, "network": "eip155:8453", "max_usdc": "0.01" }, "results": [ { "rank": 1, "method": "POST", "endpoint": "https://search.example.com/v1/web/search", "live_check": { "cached": false, "pay_to": "0x1234567890AbcdEF1234567890aBcdef12345678", "status": "live_matches_listing", "network": "eip155:8453", "checked_at": "2026-10-25T09:14:03Z", "latency_ms": 312, "http_status": 402, "price_drift": "0", "x402_version": 2, "live_price_usdc": "0.005", "listed_price_usdc": "0.005", "payto_matches_listing": true }, "price_usdc": "0.005", "rank_score": 118.787, "description": "Live web search for AI agents: ranked results with title, URL, snippet, publish date and source, with automatic provider failover.", "how_to_call": { "url": "https://search.example.com/v1/web/search", "json": { "query": "x402 facilitator fees", "max_results": 5 }, "method": "POST", "payment": { "flow": "x402 exact: an unpaid request returns PAYMENT-REQUIRED; the retry carries the signed accepts entry in PAYMENT-SIGNATURE.", "asset": "USDC", "pay_to": "0x1234567890AbcdEF1234567890aBcdef12345678", "scheme": "exact", "network": "eip155:8453", … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ontario-protocol-x402-api-finder-07449a0d/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from ontarioprotocol.com](https://www.zero.xyz/host/ontarioprotocol.com/llms.txt)