{"id":"3c19867e-babd-4006-bad9-7c9c4b6ef4de","shortId":"adLRPV","kind":"x402","title":"x402-gated email data endpoint on Base, pay $0.02 per request in USDC.","tagline":"x402-gated email data endpoint on Base, pay $0.02 per request in USDC.","description":"This endpoint at lowpaymentfee.com provides premium API access to an email-related resource (specifically `/api/v1/emails/51`) via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call API endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request.\n\nPayment is settled on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The x402 challenge confirms the endpoint is live and accepts POST requests with a maximum amount of 20,000 base units (i.e., $0.02 given USDC's 6 decimals). No API keys are required; callers simply attach an `X-PAYMENT` header with a valid x402 payment proof. The platform advertises no rate limits and instant access.\n\nThe specific functionality of the `/api/v1/emails/51` endpoint is not documented beyond the generic label \"Premium API Access.\" The crawled docs, pricing, and README pages all returned only a \"Connect wallet\" stub with no additional technical documentation, request/response schemas, or usage examples. Because of this, the exact input parameters and response format remain unknown. The platform appears to be a demonstration or early-stage x402 marketplace rather than a mature, fully-documented API provider.","tags":[],"capabilities":["x402-payment","usdc-base","pay-per-request","email-data","no-api-key","post-method"],"categories":["data","email"],"synonyms":["email API","x402 email endpoint","pay-per-call email","USDC API","Base network API","lowpaymentfee","premium email access"],"warnings":["No documentation available — all doc/pricing/README pages return only a 'Connect wallet' stub with no content.","The exact purpose of /api/v1/emails/51 is unknown; 'Premium API Access' is a generic placeholder label.","No request or response schema is provided; integration requires trial-and-error.","The platform may be a demo or early-stage project rather than a production service."],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/51","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/emails/51","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.300","qualityRationale":"The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is zero documentation on what this specific endpoint does, what inputs it accepts, or what it returns. Docs pages are empty stubs. The endpoint label is entirely 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'0.02':10,24,81,117 '000':113 '0x833589fcd6edb6e08f4c7c32d4f71b54bda02913':94 '20':112 '6':121 'Base network API' 'USDC API' 'accept':104 'access':36,150,167 'addit':184 'advertis':144 'ai':70 'amount':110 'analyt':69 'api':35,65,124,166,224 'appear':206 'attach':130 'base':8,22,89,114 'beyond':161 'broader':55 'call':64 'caller':128 'challeng':97 'confirm':98 'connect':179 'contract':93 'crawl':169 'data':5,19,68 'decim':122 'demonstr':210 'doc':170 'document':160,186,223 'dozen':59 'earli':213 'early-stag':212 'email':4,18,40 'email API' 'email-data' 'email-rel':39 'endpoint':6,20,30,66,100,157 'exact':196 'exampl':191 'financ':73 'format':201 'fulli':222 'fully-docu':221 'function':153 'gate':3,17 'generic':163 'given':118 'header':135 'i.e':116 'infrastructur':76 'input':197 'instant':149 'key':125 'label':164 'learn':72 'limit':147 'live':102 'lowpaymentfee' 'lowpaymentfee.com':32 'machin':71 'marketplac':216 'matur':220 'maximum':109 'network':90 'no-api-key' 'offer':58 'page':174 'paramet':198 'part':52 'pay':9,23,62 'pay-per-cal':61 'pay-per-call email' 'pay-per-request' 'payment':48,84,134,140 'per':11,25,63,82 'platform':56,143,205 'post':105 'post-method' 'premium':34,165 'premium email access' 'price':79,171 'proof':141 'protocol':49 'provid':33,225 'rate':146 'rather':217 'readm':173 'relat':41 'remain':202 'request':12,26,83,106 'request/response':187 'requir':127 'resourc':42 'respons':200 'return':176 'schema':188 'settl':86 'simpli':129 'span':67 'specif':43,152 'stage':214 'stub':181 'technic':185 'unit':115 'unknown':203 'usag':190 'usdc':14,28,92,119 'usdc-base' 'use':91 'util':77 'valid':138 'via':45 'wallet':180 'web3':74 'x':133 'x-payment':132 'x402':2,16,47,96,139,215 'x402 email endpoint' 'x402-gated':1,15 'x402-payment'","prices":[{"id":"70a3046d-df82-4a50-8f86-936b950c0592","listingId":"3c19867e-babd-4006-bad9-7c9c4b6ef4de","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/emails/51","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:11.296Z"}],"sources":[{"listingId":"3c19867e-babd-4006-bad9-7c9c4b6ef4de","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/51","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:11.296Z","lastSeenAt":"2026-04-22T08:32:02.092Z"}],"details":{"listingId":"3c19867e-babd-4006-bad9-7c9c4b6ef4de","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/51 \\\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":"The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units in USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/emails/51"},{"claim":"All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access","source_url":"https://lowpaymentfee.com"},{"claim":"USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/51"},{"claim":"Docs, pricing, README, and API pages return only a 'Connect wallet' stub","source_url":"https://lowpaymentfee.com/docs"}],"useCases":["Fetching email-related data on a per-request payment basis without API key registration","Demonstrating x402 payment protocol integration for agent-to-agent commerce","Accessing a low-cost micro-payment API endpoint settled on Base L2"],"bestFor":["Developers experimenting with x402 payment flows","Agents needing pay-per-call email data without subscription commitments","Projects requiring USDC-settled micro-transactions on Base"],"notFor":["Production email workflows requiring documented schemas and SLAs","Bulk email sending or SMTP relay services","Users who need detailed API documentation before integrating"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:21.123Z"},"updatedAt":"2026-04-22T08:32:02.092Z"}}