{"id":"08a562ac-b911-4c28-9992-78142b840b52","shortId":"4m5Ahw","kind":"x402","title":"Pay-per-call email data endpoint on Base via x402, settled in USDC at $0.02/request.","tagline":"Pay-per-call email data endpoint on Base via x402, settled in USDC at $0.02/request.","description":"This endpoint at `/api/v1/emails/57` is part of the lowpaymentfee.com platform, which offers a collection of pay-per-request APIs spanning data & analytics, AI/ML, finance, infrastructure, and more. All endpoints use the x402 payment protocol, settling in USDC on the Base network. The specific resource at `/emails/57` is labeled \"Premium API Access\" and accepts POST requests. The price is 20,000 base units of USDC (6 decimals), which equals $0.02 per request.\n\nThe broader lowpaymentfee.com platform advertises a uniform $0.02/request pricing model with no API keys, no rate limits, no minimums, and instant access. However, the `/api/v1/emails/57` endpoint is not listed among the publicly advertised API categories on the homepage (which cover analytics, AI, finance, and utilities). The exact data returned by this email-related endpoint is not documented in the crawled material — there is no OpenAPI spec, no example request/response, and the docs/pricing/README pages all render only a \"Connect wallet\" prompt with no further content.\n\nBecause the endpoint does return a valid 402 challenge with a well-formed x402 payload, it is confirmed live. The payment is routed to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` on Base. The timeout for payment is 300 seconds. Without documentation on what the endpoint actually returns, agents should treat this as an opaque premium data endpoint until more information is available.","tags":[],"capabilities":["x402-payment","usdc-settlement","base-network","pay-per-request","email-data","post-method"],"categories":["data"],"synonyms":["email API","premium email endpoint","x402 email","pay-per-call API","lowpaymentfee","USDC API","Base network API","micropayment API"],"warnings":["The /api/v1/emails/57 endpoint is not listed among the provider's publicly advertised APIs — its purpose and response format are undocumented.","All documentation pages (docs, pricing, README, api) render only a 'Connect wallet' prompt with no usable content.","No OpenAPI spec, no example requests or responses, and no schema for the returned data are available.","The exact nature of 'email' data served is unknown — could be sensitive/regulated content."],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/57","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/57","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 challenge, but there is no OpenAPI spec, no documentation of request/response schemas, and the specific /emails/57 resource is not listed on the provider's homepage. The docs, pricing, and README pages are empty beyond a wallet-connect prompt. The actual data returned is entirely 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'/emails/57':81 '/request':17,34,115 '0.02':16,33,104,114 '000':95 '0x1a2b13e97f5f837c8f9fa1f95a1484b7c70d85f3':219 '0x833589fcd6edb6e08f4c7c32d4f71b54bda02913':223 '20':94 '300':231 '402':200 '6':100 'Base network API' 'USDC API' 'accept':88 'access':86,129 'actual':239 'address':218 'advertis':111,140 'agent':241 'ai':149 'ai/ml':58 'among':137 'analyt':57,148 'api':54,85,120,141 'avail':255 'base':9,26,75,96,225 'base-network' 'broader':108 'call':4,21 'categori':142 'challeng':201 'collect':48 'confirm':211 'connect':186 'content':192 'contract':222 'cover':147 'crawl':168 'data':6,23,56,155,249 'decim':101 'docs/pricing/readme':180 'document':165,234 'email':5,22,160 'email API' 'email-data' 'email-rel':159 'endpoint':7,24,36,64,133,162,195,238,250 'equal':103 'exact':154 'exampl':176 'financ':59,150 'form':206 'homepag':145 'howev':130 'inform':253 'infrastructur':60 'instant':128 'key':121 'label':83 'limit':124 'list':136 'live':212 'lowpaymentfee' 'lowpaymentfee.com':43,109 'materi':169 'micropayment API' 'minimum':126 'model':117 'network':76 'offer':46 'opaqu':247 'openapi':173 'page':181 'part':40 'pay':2,19,51 'pay-per-cal':1,18 'pay-per-call API' 'pay-per-request':50 'payload':208 'payment':68,214,229 'per':3,20,52,105 'platform':44,110 'post':89 'post-method' 'premium':84,248 'premium email endpoint' 'price':92,116 'prompt':188 'protocol':69 'public':139 'rate':123 'relat':161 'render':183 'request':53,90,106 'request/response':177 'resourc':79 'return':156,197,240 'rout':216 'second':232 'settl':12,29,70 'span':55 'spec':174 'specif':78 'timeout':227 'treat':243 'uniform':113 'unit':97 'usdc':14,31,72,99,221 'usdc-settlement' 'use':65,220 'util':152 'valid':199 'via':10,27 'wallet':187 'well':205 'well-form':204 'without':233 'x402':11,28,67,207 'x402 email' 'x402-payment'","prices":[{"id":"65d6e572-41fd-4d70-89da-a19d3bfe2028","listingId":"08a562ac-b911-4c28-9992-78142b840b52","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/57","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:12.409Z"}],"sources":[{"listingId":"08a562ac-b911-4c28-9992-78142b840b52","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/57","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:12.409Z","lastSeenAt":"2026-04-25T15:33:11.498Z"}],"details":{"listingId":"08a562ac-b911-4c28-9992-78142b840b52","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/57 \\\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":"The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/emails/57"},{"claim":"The platform advertises $0.02/request pricing with no API keys, no rate limits, and no minimums","source_url":"https://lowpaymentfee.com"},{"claim":"USDC contract address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 is used on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/57"},{"claim":"The homepage lists API categories for analytics, AI, finance, and infrastructure but does not list an emails endpoint","source_url":"https://lowpaymentfee.com"}],"useCases":["Retrieving email-related data on a per-request payment basis","Agent-driven data acquisition without API key management","Programmatic access to premium content via x402 micropayments"],"bestFor":["Agents that need keyless, pay-per-call data access","Developers experimenting with x402 payment protocol on Base","Low-volume consumers who want no subscription commitment"],"notFor":["Users who need detailed API documentation before purchasing","High-volume batch email processing (no documented rate limits but no bulk discount either)","Anyone requiring non-USDC or non-Base payment settlement"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:20.785Z"},"updatedAt":"2026-04-25T15:33:11.498Z"}}