{"id":"503a4b75-3ef9-45a3-a9d9-3b27783dd29c","shortId":"wF9hAJ","kind":"x402","title":"Pay-per-call email API on Base via x402 — $0.02/request in USDC, no API keys required.","tagline":"Pay-per-call email API on Base via x402 — $0.02/request in USDC, no API keys required.","description":"This endpoint at lowpaymentfee.com provides a premium email-related API accessible via the x402 payment protocol. The specific resource `/api/v1/emails/5` accepts POST requests and charges $0.02 per call (20,000 base units of USDC on the Base network, where USDC has 6 decimals). Payment is handled inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.\n\nThe provider operates a broader platform offering dozens of pay-per-call endpoints across categories including data & analytics, AI/ML (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints share the same $0.02/request pricing model and settle on the Base network using USDC.\n\nDocumentation is extremely sparse — the docs, API, pricing, and README pages all render only a \"Connect wallet\" prompt with no substantive content. The specific functionality of the `/api/v1/emails/5` endpoint is not documented; the path suggests it may retrieve or process a specific email resource (ID 5), but the exact input/output schema is unknown. The x402 challenge confirms the endpoint is live and accepting payment-gated POST requests.","tags":[],"capabilities":["x402-payment","usdc-base-network","pay-per-call","email-api","no-api-key","no-rate-limits"],"categories":["email","infrastructure"],"synonyms":["email endpoint","paid email API","x402 email","USDC email API","Base network API","lowpaymentfee","micropayment email"],"warnings":["No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.","The exact purpose and input/output schema of /api/v1/emails/5 is unknown; the path suggests a specific email resource but this is speculative.","No OpenAPI spec or AI plugin manifest found.","The endpoint name 'Premium API Access' is generic and does not describe the actual functionality."],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/5","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/5","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.300","qualityRationale":"The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation for the /api/v1/emails/5 endpoint — no input schema, no output schema, no examples, and no explanation of what it actually does. The docs/pricing/README pages are all empty. This is effectively a stub 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'/request':12,30,148 '0.02':11,29,63,147 '000':67 '20':66 '5':204 '6':79 'Base network API' 'USDC email API' 'accept':58,221 'access':48 'account':94 'across':114 'ai/ml':119 'analysi':121 'analyt':118 'api':6,16,24,34,47,92,165 'base':8,26,68,74,155 'broader':104 'call':4,22,65,112 'categori':115 'challeng':214 'charg':62 'classif':123 'confirm':215 'connect':174 'content':180 'convers':140 'data':117 'decim':80 'doc':164 'document':159,190 'dozen':107 'email':5,23,45,201 'email endpoint' 'email-api' 'email-rel':44 'embed':124 'endpoint':38,113,143,187,217 'estim':134 'exact':207 'exchang':129 'extrem':161 'feed':128 'financ':125 'function':183 'gas':133 'gate':224 'generat':141 'geocod':138 'handl':83 'header':90 'id':203 'includ':116 'infrastructur':136 'inlin':84 'input/output':208 'key':17,35,93 'limit':97 'live':219 'lowpaymentfee' 'lowpaymentfee.com':40 'may':195 'micropayment email' 'model':150 'network':75,156 'no-api-key' 'no-rate-limits' 'offer':106 'oper':102 'page':169 'paid email API' 'path':192 'pay':2,20,110 'pay-per-cal':1,19,109 'pay-per-call' 'payment':52,81,89,223 'payment-g':222 'per':3,21,64,111 'platform':105 'post':59,225 'premium':43 'price':127,149,166 'process':198 'prompt':176 'protocol':53 'provid':41,101 'quot':132 'rate':96,130 'readm':168 'relat':46 'render':171 'request':60,226 'requir':18,36,99 'resourc':56,202 'retriev':196 'schema':209 'sentiment':120 'settl':152 'share':144 'spars':162 'specif':55,182,200 'substant':179 'suggest':193 'summar':122 'token':131 'unit':69 'unknown':211 'usdc':14,32,71,77,158 'usdc-base-network' 'use':157 'util':137 'valid':139 'via':9,27,49,85 'wallet':175 'web3':126 'x':88 'x-payment':87 'x402':10,28,51,213 'x402 email' 'x402-payment'","prices":[{"id":"a33a8f5f-d00a-44ac-8679-410b228641b0","listingId":"503a4b75-3ef9-45a3-a9d9-3b27783dd29c","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/5","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:12.372Z"}],"sources":[{"listingId":"503a4b75-3ef9-45a3-a9d9-3b27783dd29c","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/5","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:12.372Z","lastSeenAt":"2026-04-22T07:32:11.003Z"}],"details":{"listingId":"503a4b75-3ef9-45a3-a9d9-3b27783dd29c","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/5 \\\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 requesting 20,000 base units of USDC on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/5"},{"claim":"All endpoints are priced at $0.02/request with no API keys, no rate limits, and instant access on Base network","source_url":"https://lowpaymentfee.com"},{"claim":"The platform offers endpoints across data & analytics, AI/ML, finance & Web3, and infrastructure categories","source_url":"https://lowpaymentfee.com"},{"claim":"USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/5"}],"useCases":["Accessing email data or processing via a single paid API call","Integrating pay-per-use email functionality into agent workflows","Testing x402 payment protocol integrations with a low-cost endpoint"],"bestFor":["Developers experimenting with x402 payment-gated APIs","Agents needing no-signup, no-key API access on Base","Low-volume, pay-as-you-go email operations"],"notFor":["High-volume email sending or marketing automation (no documented bulk support)","Users needing detailed API documentation or guaranteed SLAs","Anyone without a Base-network USDC wallet"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:20.757Z"},"updatedAt":"2026-04-22T07:32:11.003Z"}}