{"id":"eee98273-b9a7-40f9-81b6-c60fe0cffcca","shortId":"53qkfC","kind":"x402","title":"Pay-per-request API collection on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.","tagline":"Pay-per-request API collection on Base via x402 — data, AI, finance, and utility endpoints at $0.02/call.","description":"lowpaymentfee.com hosts a collection of pay-per-request API endpoints accessible via the x402 payment protocol on the Base network. The specific endpoint at `/api/v1/collections/2` is labeled \"Premium API Access\" and accepts POST requests, settling payments in USDC (contract 0x8335…2913) on Base. The x402 challenge advertises a maxAmountRequired of 20,000 base units, which at 6 decimals for USDC equals $0.02 per request.\n\nThe provider's landing page lists four categories of APIs: 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 with no API keys, no rate limits, and no minimum commitments required.\n\nDocumentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a \"Connect wallet\" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any endpoint. The `/api/v1/collections/2` endpoint likely serves as a bundled or collection-level access point, but its exact input parameters and response format are unknown from the available material.","tags":[],"capabilities":["x402-payment","per-request-billing","usdc-settlement","base-network","data-analytics","ai-inference","sentiment-analysis","text-summarization","classification","embeddings","finance-data","geocoding","no-api-key"],"categories":["ai","data","finance","infrastructure"],"synonyms":["pay-per-call API","x402 API","micropayment API","USDC API","Base network API","low fee API","crypto-paid API"],"warnings":["No OpenAPI or schema documentation available — request/response formats are unknown","All doc pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content","The specific purpose and input format of /api/v1/collections/2 is not documented","No rate limit or SLA information provided"],"endpointUrl":"https://lowpaymentfee.com/api/v1/collections/2","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/2","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.350","qualityRationale":"The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no OpenAPI schema, no request/response examples, and all documentation pages are empty beyond a wallet-connect prompt. The exact functionality of the /collections/2 endpoint is 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'/api/v1/collections/2':64,205 '/call':19,38 '/docs':172 '/pricing':174 '/readme':176 '0.02':18,37,101,152 '000':91 '0x8335':79 '20':90 '2913':80 '6':96 'Base network API' 'USDC API' 'accept':71 'access':50,69,216 'advertis':86 'ai':12,31,121 'ai-inference' 'analysi':125 'analyt':115 'api':5,24,48,68,113,157 'avail':230 'base':8,27,58,82,92 'base-network' 'bundl':211 'categori':111 'challeng':85 'classif':128 'classification' 'collect':6,25,42,214 'collection-level':213 'commit':165 'connect':182 'content':188 'contract':78 'convers':145 'crypto-paid API' 'data':11,30,114,118 'data-analytics' 'decim':97 'detail':199 'document':167,200 'embed':129 'embeddings' 'endpoint':16,35,49,62,148,203,206 'equal':100 'estim':139 'exact':220 'exampl':196 'exchang':134 'export':119 'extrem':169 'feed':133 'financ':13,32,130 'finance-data' 'format':225 'four':110 'gas':138 'generat':146 'geocod':143 'geocoding' 'host':40 'infrastructur':141 'input':221 'insight':120 'key':158 'label':66 'land':107 'learn':123 'level':215 'like':207 'limit':161 'list':109,150 'low fee API' 'lowpaymentfee.com':39 'machin':122 'materi':231 'maxamountrequir':88 'metric':116 'micropayment API' 'minimum':164 'network':59 'no-api-key' 'openapi':192 'page':108,177 'paramet':222 'pay':2,21,45 'pay-per-call API' 'pay-per-request':1,20,44 'payment':54,75 'per':3,22,46,102,153 'per-request-billing' 'point':217 'post':72 'premium':67 'price':132 'prompt':184 'protocol':55 'provid':105 'quot':137 'rate':135,160 'render':179 'report':117 'request':4,23,47,73,103,154 'request/response':195 'requir':166 'respons':224 'schema':193 'sentiment':124 'sentiment-analysis' 'serv':208 'settl':74 'spars':170 'specif':61 'summar':127 'text':126 'text-summarization' 'token':136 'unit':93 'unknown':227 'usdc':77,99 'usdc-settlement' 'util':15,34,142 'valid':144 'via':9,28,51 'wallet':183 'web3':131 'x402':10,29,53,84 'x402 API' 'x402-payment'","prices":[{"id":"b935ec70-3866-4657-986e-52bdcc55b8f2","listingId":"eee98273-b9a7-40f9-81b6-c60fe0cffcca","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/2","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T22:29:48.891Z"}],"sources":[{"listingId":"eee98273-b9a7-40f9-81b6-c60fe0cffcca","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/collections/2","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T22:29:48.891Z","lastSeenAt":"2026-04-22T04:02:20.476Z"}],"details":{"listingId":"eee98273-b9a7-40f9-81b6-c60fe0cffcca","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/collections/2 \\\n  -H \"Content-Type: application/json\" \\\n  -H \"X-PAYMENT: <x402-payment-token>\" \\\n  -d '{}'","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"The x402 challenge advertises maxAmountRequired of 20000 base units in USDC on Base network","source_url":"https://lowpaymentfee.com/api/v1/collections/2"},{"claim":"All endpoints are listed at $0.02 per request with no API keys, no rate limits, and no minimums","source_url":"https://lowpaymentfee.com"},{"claim":"Four categories of APIs are offered: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure","source_url":"https://lowpaymentfee.com"},{"claim":"Documentation pages render only a Connect wallet prompt with no further content","source_url":"https://lowpaymentfee.com/docs"}],"useCases":["Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management","Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis","Running data analytics queries and exporting data with instant crypto-settled micropayments","Using utility services like geocoding, validation, and conversion without subscription commitments"],"bestFor":["Agents or developers who want keyless, pay-as-you-go API access settled in USDC on Base","Low-volume or bursty workloads where per-request pricing avoids subscription overhead","x402-compatible AI agents that can autonomously pay for API calls"],"notFor":["High-volume production workloads needing SLAs, rate limit guarantees, or detailed documentation","Users who need fiat billing or cannot transact in USDC on the Base network","Developers requiring well-documented request/response schemas before integration"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:25.22Z"},"updatedAt":"2026-04-22T04:02:20.476Z"}}