{"id":"f3a5ebb7-ef65-485b-ba95-1b8b2b156e0f","shortId":"nvM2LQ","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":"lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The `/api/v1/payments/204` endpoint is described as \"Premium API Access\" and accepts USDC payments at a maximum cost of $0.02 per request (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.\n\nThe broader platform advertises 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. Payments settle in USDC on the Base L2 network to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3.\n\nDocumentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a \"Connect wallet\" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The specific functionality behind the `/api/v1/payments/204` endpoint is unclear beyond its title. Prospective users should be aware that the actual capabilities of each endpoint are unverified and undocumented.","tags":[],"capabilities":["x402-payment","usdc-settlement","base-network","pay-per-request","no-api-key","json-response","post-method"],"categories":["api-gateway","payments"],"synonyms":["x402 API","pay-per-call API","USDC micropayment API","Base network API","lowpaymentfee","premium API access","crypto-paid API"],"warnings":["No OpenAPI or schema documentation available — endpoint behavior is unknown beyond its title","All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no technical content","The specific purpose of /api/v1/payments/204 ('Premium API Access') is vague and undifferentiated","No request or response examples are available anywhere in the crawled material"],"endpointUrl":"https://lowpaymentfee.com/api/v1/payments/204","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/payments/204","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.300","qualityRationale":"The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples. The actual functionality behind this specific endpoint is 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'/api/v1/payments/204':53,209 '/docs':172 '/pricing':174 '/readme':176 '/request':13,28 '0.02':12,27,70,152 '000':74 '0x1a2b13e97f5f837c8f9fa1f95a1484b7c70d85f3':166 '20':73 '6':80 'Base network API' 'USDC micropayment API' 'accept':62 'access':7,22,42,60 'across':111 'actual':223 'address':165 'advertis':109 'ai':121 'analysi':125 'analyt':115 'api':6,21,40,59,83 'attach':94 'avail':203 'awar':220 'base':9,24,50,75,161 'base-network' 'behind':207 'beyond':213 'broader':107 'call':4,19 'caller':92 'capabl':224 'categori':113 'classif':128 'collect':34 'commit':89 'connect':182 'convers':145 'cost':68 'crypto-paid API' 'data':114,118 'decim':81 'describ':56 'detail':189 'document':167,198 'embed':129 'endpoint':41,54,110,148,210,227 'estim':139 'exampl':201 'exchang':134 'export':119 'extrem':169 'feed':133 'financ':130 'four':112 'function':206 'gas':138 'generat':146 'geocod':143 'header':99 'host':32 'infrastructur':141 'insight':120 'json-response' 'key':84 'l2':162 'learn':123 'limit':86 'list':150 'lowpaymentfee' 'lowpaymentfee.com':31 'machin':122 'maximum':67 'metric':116 'network':51,163 'no-api-key' 'openapi':193 'page':177 'pay':2,17,37 'pay-per-cal':1,16 'pay-per-call API' 'pay-per-request':36 'payload':202 'payment':46,64,98,104,155 'per':3,18,38,71,153 'platform':108 'post-method' 'premium':5,20,58 'premium API access' 'price':132 'prompt':184 'proof':105 'prospect':216 'protocol':47 'quot':137 'rate':85,135 'render':179 'report':117 'request':39,72,154 'request/response':196 'requir':91 'schema':197 'sentiment':124 'settl':156 'simpli':93 'spars':170 'spec':194 'specif':205 'summar':127 'technic':188 'text':126 'titl':215 'token':136 'unclear':212 'undocu':231 'unit':76 'unverifi':229 'upfront':88 'usdc':15,30,63,78,158 'usdc-settlement' 'user':217 'util':142 'valid':102,144 'via':10,25,43 'wallet':183 'web3':131 'x':97 'x-payment':96 'x402':11,26,45,103 'x402 API' 'x402-payment'","prices":[{"id":"6425619e-522c-45a4-a4be-1b53aade43c6","listingId":"f3a5ebb7-ef65-485b-ba95-1b8b2b156e0f","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/payments/204","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T18:49:56.577Z"}],"sources":[{"listingId":"f3a5ebb7-ef65-485b-ba95-1b8b2b156e0f","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/payments/204","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T18:49:56.577Z","lastSeenAt":"2026-04-23T14:01:23.825Z"}],"details":{"listingId":"f3a5ebb7-ef65-485b-ba95-1b8b2b156e0f","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/payments/204 \\\n  -H \"Content-Type: application/json\" \\\n  -H \"X-PAYMENT: <x402-payment-proof>\"","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"Endpoint returns 402 with x402 challenge advertising USDC on Base network at maxAmountRequired 20000","source_url":"https://lowpaymentfee.com/api/v1/payments/204"},{"claim":"USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","source_url":"https://lowpaymentfee.com/api/v1/payments/204"},{"claim":"Platform lists endpoints at $0.02/request with no API keys, no rate limits, instant access on Base network","source_url":"https://lowpaymentfee.com"},{"claim":"Categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure","source_url":"https://lowpaymentfee.com"}],"useCases":["Accessing premium API functionality with per-request USDC micropayments on Base","Agent-driven workflows that need keyless, pay-as-you-go API access","Testing x402 payment protocol integrations against a live endpoint"],"bestFor":["Developers experimenting with x402 payment flows","Agents needing keyless API access with crypto micropayments","Low-volume, on-demand API consumption without subscriptions"],"notFor":["Production workloads requiring documented, well-specified API contracts","Users who need detailed request/response schemas before integration","High-throughput use cases where $0.02/request adds up significantly"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:14:08.478Z"},"updatedAt":"2026-04-23T14:01:23.825Z"}}