{"id":"c60431c8-c57c-465f-90f0-3ab0727c23c7","shortId":"FxR5av","kind":"x402","title":"Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.","tagline":"Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.","description":"This endpoint at lowpaymentfee.com provides \"Premium API Access\" via the x402 payment protocol. The specific resource at `/api/v1/charges/231` accepts POST requests and charges up to 20,000 base units of USDC (0x8335…2913) on the Base network, which equals $0.02 per request (USDC uses 6 decimals). Payment is handled inline via the X-PAYMENT header with no API keys or accounts required.\n\nThe broader lowpaymentfee.com platform advertises a suite of endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at $0.02 per request. However, the specific endpoint being listed here (`/api/v1/charges/231`) is labeled only as \"Premium API Access\" with no further documentation on what data or functionality it returns.\n\nThe endpoint is live and returns a valid x402 challenge (HTTP 402) with a 300-second payment timeout. No OpenAPI schema, request/response examples, or detailed documentation were found in the crawl — the docs, pricing, API, and README pages all rendered only a \"Connect wallet\" prompt with no substantive content. Because of this, the actual behavior and response format of this specific endpoint remain unknown.","tags":[],"capabilities":["x402-payment","usdc-base-network","pay-per-request","no-api-key","post-endpoint"],"categories":["api-gateway","payments"],"synonyms":["x402 API","pay-per-call API","USDC micropayment endpoint","Base network API","lowpaymentfee","premium API access","crypto-paid API"],"warnings":["No documentation available — docs, pricing, API, and README pages all render only 'Connect wallet' with no content.","The specific functionality of /api/v1/charges/231 ('Premium API Access') is not described anywhere; it is unclear what this endpoint actually returns.","No OpenAPI spec or output schema beyond basic HTTP method metadata.","No request body schema or response examples available."],"endpointUrl":"https://lowpaymentfee.com/api/v1/charges/231","protocol":"x402","transport":"http","auth":{"type":"x402","details":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","extra":{"name":"USD Coin","version":"2"},"payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","scheme":"exact","network":"base","mimeType":"application/json","resource":"https://lowpaymentfee.com/api/v1/charges/231","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.300","qualityRationale":"The endpoint is live and returns a valid x402 402 challenge, but there is no documentation, no OpenAPI schema, no request/response examples, and the actual functionality behind 'Premium API Access' at /api/v1/charges/231 is completely undocumented. All doc pages returned only a wallet-connect 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'/request':13,28 '0.02':12,27,70,144 '000':57 '0x8335':62 '20':56 '2913':63 '300':187 '402':184 '6':75 'Base network API' 'USDC micropayment endpoint' 'accept':49 'access':7,22,38,161 'account':92 'across':103 'actual':226 'advertis':98 'ai':113 'analysi':117 'analyt':107 'api':6,21,37,89,160,207 'base':9,24,58,66 'behavior':227 'broader':95 'call':4,19 'categori':105 'challeng':182 'charg':53 'classif':120 'connect':215 'content':221 'convers':137 'crawl':203 'crypto-paid API' 'data':106,110,168 'decim':76 'detail':197 'doc':205 'document':165,198 'embed':121 'endpoint':32,102,140,150,174,234 'equal':69 'estim':131 'exampl':195 'exchang':126 'export':111 'feed':125 'financ':122 'format':230 'found':200 'four':104 'function':170 'gas':130 'generat':138 'geocod':135 'handl':79 'header':86 'howev':147 'http':183 'infrastructur':133 'inlin':80 'insight':112 'key':90 'label':156 'learn':115 'list':142,152 'live':176 'lowpaymentfee' 'lowpaymentfee.com':34,96 'machin':114 'metric':108 'network':67 'no-api-key' 'openapi':192 'page':210 'pay':2,17 'pay-per-cal':1,16 'pay-per-call API' 'pay-per-request' 'payment':42,77,85,189 'per':3,18,71,145 'platform':97 'post':50 'post-endpoint' 'premium':5,20,36,159 'premium API access' 'price':124,206 'prompt':217 'protocol':43 'provid':35 'quot':129 'rate':127 'readm':209 'remain':235 'render':212 'report':109 'request':51,72,146 'request/response':194 'requir':93 'resourc':46 'respons':229 'return':172,178 'schema':193 'second':188 'sentiment':116 'specif':45,149,233 'substant':220 'suit':100 'summar':119 'text':118 'timeout':190 'token':128 'unit':59 'unknown':236 'usdc':15,30,61,73 'usdc-base-network' 'use':74 'util':134 'valid':136,180 'via':10,25,39,81 'wallet':216 'web3':123 'x':84 'x-payment':83 'x402':11,26,41,181 'x402 API' 'x402-payment'","prices":[{"id":"2470c7c1-f4d3-4c24-9f4d-fcafa46be8f0","listingId":"c60431c8-c57c-465f-90f0-3ab0727c23c7","amountUsd":null,"unit":"per_call","nativeCurrency":"USD COIN","nativeAmount":"20000","chain":"base","payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","paymentMethod":"x402-usd coin","isPrimary":true,"details":{"scheme":"exact","mime_type":"application/json","accepts_all":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","extra":{"name":"USD Coin","version":"2"},"payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","scheme":"exact","network":"base","mimeType":"application/json","resource":"https://lowpaymentfee.com/api/v1/charges/231","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T18:44:38.103Z"}],"sources":[{"listingId":"c60431c8-c57c-465f-90f0-3ab0727c23c7","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/charges/231","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T18:44:38.103Z","lastSeenAt":"2026-04-24T02:32:12.387Z"}],"details":{"listingId":"c60431c8-c57c-465f-90f0-3ab0727c23c7","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/charges/231 \\\n  -H \"Content-Type: application/json\" \\\n  -H \"X-PAYMENT: <x402-payment-token>\"","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"Endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Base network","source_url":"https://lowpaymentfee.com/api/v1/charges/231"},{"claim":"All endpoints listed at $0.02 per request with no API keys, no rate limits, and instant access","source_url":"https://lowpaymentfee.com"},{"claim":"Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories","source_url":"https://lowpaymentfee.com"},{"claim":"USDC contract address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base","source_url":"https://lowpaymentfee.com/api/v1/charges/231"}],"useCases":["Programmatic access to a premium API resource without needing an API key or subscription","Agent-driven workflows that pay per call using USDC on Base","Testing x402 payment protocol integrations against a live endpoint"],"bestFor":["Developers experimenting with x402 payment flows","Agents that need keyless, pay-as-you-go API access on Base","Low-volume consumers who want no commitments or rate limits"],"notFor":["Users who need detailed documentation or guaranteed SLAs before integrating","High-volume production workloads where per-request crypto payments add overhead","Anyone who needs to know the exact response schema before paying"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:14:23.859Z"},"updatedAt":"2026-04-24T02:32:12.387Z"}}