{"id":"e03d45e3-38ac-49ae-9635-2f9708f54d23","shortId":"UqAPhE","kind":"x402","title":"Pay-per-request email API on Base via x402 — $0.02/call in USDC, no API keys required.","tagline":"Pay-per-request email API on Base via x402 — $0.02/call 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/40` accepts POST requests and charges $0.02 per call (20,000 base units of USDC on the Base network, where USDC uses 6 decimals). Payment is made 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-request endpoints spanning 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 L2 network using USDC.\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 description of what the `/api/v1/emails/40` endpoint specifically does or what parameters it accepts. The endpoint is confirmed live (returns a proper 402 x402 challenge), but the actual functionality behind the paywall is unknown.","tags":[],"capabilities":["x402-payment","usdc-base-network","pay-per-request","email-api","no-api-key","post-method"],"categories":["email","api-infrastructure"],"synonyms":["email API","x402 email endpoint","pay-per-call email","USDC email API","Base network API","lowpaymentfee email"],"warnings":["No documentation available — all doc/pricing/README pages show only 'Connect wallet' with no content","No OpenAPI or input/output schema provided for /api/v1/emails/40","The specific functionality of the emails/40 endpoint is completely unknown","Cannot verify what data or service is delivered after payment"],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/40","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/40","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.250","qualityRationale":"The endpoint is confirmed live with a valid 402 x402 challenge, but there is zero documentation on what the email endpoint actually does, what parameters it accepts, or what it returns. No OpenAPI schema, no examples, and all doc pages are empty. The listing is effectively a 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'/call':12,30 '/request':146 '0.02':11,29,63,145 '000':67 '20':66 '402':211 '6':79 'Base network API' 'USDC email API' 'accept':58,202 'access':48 'account':94 'actual':216 'ai/ml':117 'analysi':119 'analyt':116 'api':6,16,24,34,47,92,164 'base':8,26,68,74,153 'behind':218 'broader':104 'call':65 'challeng':213 'charg':62 'classif':121 'confirm':206 'connect':173 'content':179 'convers':138 'data':115 'decim':80 'descript':190 'doc':163 'document':158 'dozen':107 'email':5,23,45 'email API' 'email-api' 'email-rel':44 'embed':122 'endpoint':38,113,141,195,204 'estim':132 'exampl':187 'exchang':127 'extrem':160 'feed':126 'financ':123 'function':217 'gas':131 'generat':139 'geocod':136 'header':90 'infrastructur':134 'inlin':84 'key':17,35,93 'l2':154 'limit':97 'live':207 'lowpaymentfee email' 'lowpaymentfee.com':40 'made':83 'model':148 'network':75,155 'no-api-key' 'offer':106 'openapi':183 'oper':102 'page':168 'paramet':200 'pay':2,20,110 'pay-per-call email' 'pay-per-request':1,19,109 'payment':52,81,89 'paywal':220 'per':3,21,64,111 'platform':105 'post':59 'post-method' 'premium':43 'price':125,147,165 'prompt':175 'proper':210 'protocol':53 'provid':41,101 'quot':130 'rate':96,128 'readm':167 'relat':46 'render':170 'request':4,22,60,112 'request/response':186 'requir':18,36,99 'resourc':56 'return':208 'schema':184 'sentiment':118 'settl':150 'share':142 'span':114 'spars':161 'specif':55,196 'summar':120 'token':129 'unit':69 'unknown':222 'usdc':14,32,71,77,157 'usdc-base-network' 'use':78,156 'util':135 'valid':137 'via':9,27,49,85 'wallet':174 'web3':124 'x':88 'x-payment':87 'x402':10,28,51,212 'x402 email endpoint' 'x402-payment'","prices":[{"id":"5c917261-46ff-4ccc-afa7-6ea7a476dc38","listingId":"e03d45e3-38ac-49ae-9635-2f9708f54d23","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/40","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:12.354Z"}],"sources":[{"listingId":"e03d45e3-38ac-49ae-9635-2f9708f54d23","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/40","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:12.354Z","lastSeenAt":"2026-04-22T07:32:11.003Z"}],"details":{"listingId":"e03d45e3-38ac-49ae-9635-2f9708f54d23","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/40 \\\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":"Endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/emails/40"},{"claim":"USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","source_url":"https://lowpaymentfee.com/api/v1/emails/40"},{"claim":"All endpoints priced at $0.02/request with no API keys, no rate limits, and instant access on Base network","source_url":"https://lowpaymentfee.com"},{"claim":"Platform offers endpoints across data & analytics, AI/ML, finance & Web3, and infrastructure categories","source_url":"https://lowpaymentfee.com"}],"useCases":["Sending or retrieving email data via a single paid API call","Integrating email functionality into agent workflows without managing API keys","Programmatic email operations settled in USDC on Base"],"bestFor":["Developers wanting keyless, pay-as-you-go email API access","AI agents that can settle x402 payments on Base","Users who prefer crypto micropayments over subscription billing"],"notFor":["Anyone needing documented request/response schemas before integrating","High-volume email operations where per-call pricing adds up quickly","Users without a Base-compatible USDC wallet"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:20.856Z"},"updatedAt":"2026-04-22T07:32:11.003Z"}}