{"id":"097dded5-2b96-4e79-8232-07c4e463ed68","shortId":"X4Hdt6","kind":"x402","title":"x402-gated API collection on Base — pay $0.02 per request in USDC, no keys required.","tagline":"x402-gated API collection on Base — pay $0.02 per request in USDC, no keys required.","description":"lowpaymentfee.com hosts a suite of pay-per-call APIs gated by the x402 protocol on the Base network. The specific endpoint `/api/v1/collections/48` is labeled \"Premium API Access\" and returns a standard x402 challenge requesting payment in USDC (contract 0x8335…2913 on Base) via the \"exact\" scheme. The maximum amount required is 20,000 base units of USDC (6 decimals), which equals $0.02 per request.\n\nThe broader platform advertises four categories of endpoints: 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. The platform emphasizes no API keys, no rate limits, no minimums, and instant access.\n\nThe `/api/v1/collections/48` endpoint specifically is a POST endpoint (per the outputSchema in the x402 challenge). However, the crawled documentation pages (docs, pricing, README) all returned only a \"Connect wallet\" prompt with no substantive content, so the actual request/response schema for this endpoint is unknown. Without documentation on what data this collection endpoint accepts or returns, callers will need to experiment or wait for fuller docs.","tags":[],"capabilities":["x402-payment","usdc-base","pay-per-request","no-api-key","post-endpoint","json-response"],"categories":["api-gateway","data"],"synonyms":["x402 API","pay-per-call API","USDC micropayment API","Base network API","lowpaymentfee","low payment fee API","402 payment required API"],"warnings":["No documentation available — docs, pricing, and README pages all return only a 'Connect wallet' prompt with no content.","The actual request body schema and response format for /api/v1/collections/48 are unknown; callers must discover behavior experimentally.","The endpoint name 'Premium API Access' is generic and does not describe what data or service is provided."],"endpointUrl":"https://lowpaymentfee.com/api/v1/collections/48","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/collections/48","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.400","qualityRationale":"The x402 challenge is live and well-formed, confirming the endpoint exists and its pricing ($0.02 USDC on Base). However, all documentation pages returned only 'Connect wallet' with no actual content, so the request/response schema, purpose, and behavior of this specific collection endpoint are entirely 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'0.02':9,25,95,144 '000':86 '0x8335':72 '20':85 '2913':73 '402 payment required API' '6':91 'Base network API' 'USDC micropayment API' 'accept':213 'access':60,160 'actual':197 'advertis':101 'ai':113 'amount':82 'analysi':117 'analyt':107 'api':4,20,42,59,151 'base':7,23,50,75,87 'broader':99 'call':41 'caller':216 'categori':103 'challeng':66,175 'classif':120 'collect':5,21,211 'connect':188 'content':194 'contract':71 'convers':137 'crawl':178 'data':106,110,209 'decim':92 'doc':181,225 'document':179,206 'embed':121 'emphas':149 'endpoint':54,105,140,163,168,202,212 'equal':94 'estim':131 'exact':78 'exchang':126 'experi':220 'export':111 'feed':125 'financ':122 'four':102 'fuller':224 'gas':130 'gate':3,19,43 'generat':138 'geocod':135 'host':34 'howev':176 'infrastructur':133 'insight':112 'instant':159 'json-response' 'key':15,31,152 'label':57 'learn':115 'limit':155 'list':142 'low payment fee API' 'lowpaymentfee' 'lowpaymentfee.com':33 'machin':114 'maximum':81 'metric':108 'minimum':157 'need':218 'network':51 'no-api-key' 'outputschema':171 'page':180 'pay':8,24,39 'pay-per-cal':38 'pay-per-call API' 'pay-per-request' 'payment':68 'per':10,26,40,96,145,169 'platform':100,148 'post':167 'post-endpoint' 'premium':58 'price':124,182 'prompt':190 'protocol':47 'quot':129 'rate':127,154 'readm':183 'report':109 'request':11,27,67,97,146 'request/response':198 'requir':16,32,83 'return':62,185,215 'schema':199 'scheme':79 'sentiment':116 'specif':53,164 'standard':64 'substant':193 'suit':36 'summar':119 'text':118 'token':128 'unit':88 'unknown':204 'usdc':13,29,70,90 'usdc-base' 'util':134 'valid':136 'via':76 'wait':222 'wallet':189 'web3':123 'without':205 'x402':2,18,46,65,174 'x402 API' 'x402-gated':1,17 'x402-payment'","prices":[{"id":"d216ff1c-6808-4ad7-adae-b979e7ca3c8c","listingId":"097dded5-2b96-4e79-8232-07c4e463ed68","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/collections/48","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-19T00:59:37.059Z"}],"sources":[{"listingId":"097dded5-2b96-4e79-8232-07c4e463ed68","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/collections/48","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-19T00:59:37.059Z","lastSeenAt":"2026-04-22T04:02:20.881Z"}],"details":{"listingId":"097dded5-2b96-4e79-8232-07c4e463ed68","quickStartSnippet":"# 1. Send a POST to get the 402 challenge:\ncurl -X POST https://lowpaymentfee.com/api/v1/collections/48\n# Returns 402 with x402 payment challenge in JSON body.\n# 2. Construct an X-PAYMENT header with a signed USDC payment of 20000 base units ($0.02)\n#    to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 on Base, then resend the POST.","exampleRequest":null,"exampleResponse":{"error":"X-PAYMENT header is required","accepts":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","extra":{"name":"USD Coin","version":"2"},"payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","scheme":"exact","network":"base","mimeType":"application/json","resource":"https://lowpaymentfee.com/api/v1/collections/48","description":"Premium API Access","maxAmountRequired":"20000","maxTimeoutSeconds":300}],"x402Version":1},"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"The x402 challenge requires 20,000 base units of USDC ($0.02) on Base network","source_url":"https://lowpaymentfee.com/api/v1/collections/48"},{"claim":"USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base","source_url":"https://lowpaymentfee.com/api/v1/collections/48"},{"claim":"Platform advertises $0.02/request, no API keys, no rate limits, instant access","source_url":"https://lowpaymentfee.com"},{"claim":"Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories","source_url":"https://lowpaymentfee.com"}],"useCases":["Accessing premium data or analytics behind a per-request USDC paywall","Agent-driven API consumption without pre-registration or API keys","Programmatic micropayment-gated service calls on Base L2"],"bestFor":["Developers or agents who want keyless, pay-as-you-go API access","Users already holding USDC on Base who want frictionless micropayments","Automated workflows that need on-demand API calls without subscription commitments"],"notFor":["Users who need detailed API documentation or guaranteed SLAs before integrating","High-volume consumers who would prefer bulk pricing or subscription plans","Anyone without a Base-compatible wallet or USDC holdings"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:24.721Z"},"updatedAt":"2026-04-22T04:02:20.881Z"}}