{"openapi":"3.1.0","info":{"title":"URL Uptime Checker","description":"Checks whether a website or web address is currently reachable and reports how fast it responded.","version":"1.0.0","contact":{"name":"_done","url":"https://forms.gle/5KzuSFH7p8hHtDmz7","email":"info@underscoredone.com"},"x-openapi-url":"https://url-uptime-checker.underscoredone.com/openapi.json","x-logo":{"url":"https://underscoredone.com/logo.png","altText":"_done"},"x-guidance":"Call this before treating any URL as reachable. Pass the full web address including http:// or https://. Read the 'up' field for a simple yes/no, 'status_code' for the response code, 'response_time_ms' for speed, and 'error' for the reason if it failed. Do not retry automatically on timeout unless explicitly instructed.","x-ai-instructions":"Call this before treating any URL as reachable. Pass the full web address including http:// or https://. Read the 'up' field for a simple yes/no, 'status_code' for the response code, 'response_time_ms' for speed, and 'error' for the reason if it failed. Do not retry automatically on timeout unless explicitly instructed.","x-provider":"_done — single-purpose utility APIs for developers and AI agents. Pay per call with USDC on Base Mainnet or Solana Mainnet.","x-pricing":{"model":"pay-per-call","currency":"USDC","network":"Base Mainnet or Solana Mainnet","price":"$0.01"},"x-keywords":["network","url uptime checker","website status","reachability check","uptime monitor","url validator","site down detector","http status check","utility","api","ai-agent","pay-per-call","usdc","x402"],"x-category":"network","x-provider-url":"https://underscoredone.com","x-agentcash-auth":{"mode":"paid"},"x-402":{"price":"$0.01","network":"eip155:8453","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","pay_to":"0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08","facilitator":"https://api.cdp.coinbase.com/platform/v2/x402","scheme":"exact","description":"Checks whether a website or web address is currently reachable and reports how fast it responded.","mime_type":"application/json","networks":[{"network":"eip155:8453","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","pay_to":"0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08"},{"network":"solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp","asset":"EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v","pay_to":"8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b"}]}},"paths":{"/check":{"post":{"tags":["Network"],"summary":"Checks if a given web address is currently online and reachable.","description":"Checks a web address to see if it is currently online, how fast it answered, and where it ended up after any redirection.","operationId":"handler_check_post","requestBody":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Request"}}},"required":true},"responses":{"200":{"description":"Successful response","content":{"application/json":{"schema":{"$ref":"#/components/schemas/Response"},"examples":{"success":{"summary":"Successful response","value":{"api_version":"1.0.0","url":"https://example.com","up":true,"status_code":200,"response_time_ms":184,"final_url":"https://example.com/","redirected":false,"error":null,"checked_at":"2026-07-23T04:12:09Z"}}}}}},"422":{"description":"Unprocessable — a required field is missing or the wrong type. Check the detail field for specifics.","content":{"application/json":{"schema":{"type":"object","properties":{"detail":{"type":"array"}}}}}},"402":{"description":"Payment required. Send a signed USDC payment on Base Mainnet or Solana Mainnet using the x402 protocol.","headers":{"X-Payment-Response":{"description":"x402 payment challenge — base64-encoded JSON with payment details.","schema":{"type":"string"}}}},"400":{"description":"Bad request — your input failed validation or could not be processed. Check the detail field for specifics.","content":{"application/json":{"schema":{"type":"object","properties":{"detail":{"type":"string"}}}}}}},"x-ai-instructions":"Call this before treating any URL as reachable. Pass the full web address including http:// or https://. Read the 'up' field for a simple yes/no, 'status_code' for the response code, 'response_time_ms' for speed, and 'error' for the reason if it failed. Do not retry automatically on timeout unless explicitly instructed.","x-guidance":"Call this before treating any URL as reachable. Pass the full web address including http:// or https://. Read the 'up' field for a simple yes/no, 'status_code' for the response code, 'response_time_ms' for speed, and 'error' for the reason if it failed. Do not retry automatically on timeout unless explicitly instructed.","x-payment-info":{"price":{"fixed":{"mode":"fixed","currency":"USD","amount":"0.01"}},"protocols":[{"x402":{}}]}}}},"components":{"schemas":{"HTTPValidationError":{"properties":{"detail":{"items":{"$ref":"#/components/schemas/ValidationError"},"type":"array","title":"Detail"}},"type":"object","title":"HTTPValidationError"},"Request":{"properties":{"url":{"type":"string","title":"Url","description":"The full web address to check, starting with http or https."},"follow_redirects":{"type":"boolean","title":"Follow Redirects","description":"Whether to follow the site to its final address if it sends you somewhere else, before reporting the result.","default":true},"method":{"type":"string","enum":["GET","HEAD"],"title":"Method","description":"Which kind of check to run. GET reads the whole page. HEAD only checks that the site answers, which is quicker.","default":"GET"}},"type":"object","required":["url"],"title":"Request","example":{"follow_redirects":true,"method":"GET","url":"https://example.com"}},"Response":{"properties":{"api_version":{"type":"string","title":"Api Version","description":"The version of this service that answered the request.","default":"1.0.0"},"url":{"type":"string","title":"Url","description":"The web address that was checked, exactly as it was given."},"up":{"type":"boolean","title":"Up","description":"True if the site answered at all, false if it could not be reached."},"status_code":{"anyOf":[{"type":"integer"},{"type":"null"}],"title":"Status Code","description":"The reply code the site sent back, if it answered."},"response_time_ms":{"anyOf":[{"type":"integer"},{"type":"null"}],"title":"Response Time Ms","description":"How many thousandths of a second the site took to answer, if it answered."},"final_url":{"anyOf":[{"type":"string"},{"type":"null"}],"title":"Final Url","description":"The address the site ended up at after any redirection, if it answered."},"redirected":{"type":"boolean","title":"Redirected","description":"True if the site sent you somewhere else before answering."},"error":{"anyOf":[{"type":"string"},{"type":"null"}],"title":"Error","description":"A short plain reason the check failed, or nothing if it succeeded."},"checked_at":{"type":"string","title":"Checked At","description":"The exact date and time the check was performed."}},"type":"object","required":["url","up","redirected","checked_at"],"title":"Response","example":{"api_version":"1.0.0","checked_at":"2026-07-23T04:12:09Z","final_url":"https://example.com/","redirected":false,"response_time_ms":184,"status_code":200,"up":true,"url":"https://example.com"}},"ValidationError":{"properties":{"loc":{"items":{"anyOf":[{"type":"string"},{"type":"integer"}]},"type":"array","title":"Location"},"msg":{"type":"string","title":"Message"},"type":{"type":"string","title":"Error Type"},"input":{"title":"Input"},"ctx":{"type":"object","title":"Context"}},"type":"object","required":["loc","msg","type"],"title":"ValidationError"}},"securitySchemes":{"siwx":{"type":"apiKey","in":"header","name":"SIGN-IN-WITH-X","description":"CAIP-122 wallet signature for repeat access after payment"}}},"servers":[{"url":"https://url-uptime-checker.underscoredone.com","description":"Production"}],"x402Version":2,"x-payment-accepts":[{"scheme":"exact","network":"eip155:8453","payTo":"0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"},{"scheme":"exact","network":"solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp","payTo":"8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b","asset":"EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"}]}