{"id":"ef9ba0fc-b789-49c2-b275-6ac8b04496d3","shortId":"TQXJbC","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 path `/api/v1/emails/90` suggests an email data retrieval or email-related operation, though the exact functionality is not documented beyond the generic \"Premium API Access\" label. Payment is settled on the Base network using USDC (contract 0x8335…2913) at a cost of $0.02 per request (20,000 base units with 6 decimals).\n\nThe provider operates a broader platform offering multiple API categories including data & analytics, AI/ML inference, finance/Web3, and infrastructure utilities — all priced uniformly at $0.02 per request. The x402 challenge was successfully captured, confirming the endpoint is live and accepting POST requests. No API keys or rate limits are advertised; access is granted purely through per-call USDC micropayments on Base.\n\nDocumentation is extremely sparse. The crawled docs, API, pricing, and README pages all returned only a \"Connect wallet\" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no description of what the `/api/v1/emails/90` endpoint actually returns or what input it expects. The `90` in the path may be an ID parameter, but this is unconfirmed.","tags":[],"capabilities":["x402-payment","usdc-micropayment","base-network","email-api","pay-per-request","no-api-key"],"categories":["email","data"],"synonyms":["email API","x402 email endpoint","pay-per-call email","USDC email API","Base network API","micropayment email","lowpaymentfee email"],"warnings":["No documentation available — all doc/API/pricing/README pages return only 'Connect wallet' with no content","Exact functionality of /api/v1/emails/90 is unknown; 'Premium API Access' is the only description","No request or response schema provided; integration requires trial-and-error","The '90' in the path is unexplained — may be a fixed resource ID or a parameter placeholder"],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/90","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/90","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.250","qualityRationale":"The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what this endpoint actually does, what inputs it accepts, or what it returns. No OpenAPI schema, no examples, and all doc pages are empty. The endpoint is effectively a stub 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'/request':12,30 '0.02':11,29,99,132 '000':103 '0x8335':93 '20':102 '2913':94 '6':107 '90':217 'Base network API' 'USDC email API' 'accept':147 'access':48,81,158 'actual':209 'advertis':157 'ai/ml':122 'analyt':121 'api':6,16,24,34,47,80,117,151,177 'base':8,26,88,104,169 'base-network' 'beyond':76 'broader':113 'call':4,22,165 'captur':140 'categori':118 'challeng':137 'confirm':141 'connect':186 'content':192 'contract':92 'cost':97 'crawl':175 'data':62,120 'decim':108 'descript':203 'doc':176 'document':75,170 'email':5,23,45,61,66 'email API' 'email-api' 'email-rel':44,65 'endpoint':38,143,208 'exact':71 'exampl':200 'expect':215 'extrem':172 'finance/web3':124 'function':72 'generic':78 'grant':160 'id':224 'includ':119 'infer':123 'infrastructur':126 'input':213 'key':17,35,152 'label':82 'limit':155 'live':145 'lowpaymentfee email' 'lowpaymentfee.com':40 'may':221 'micropay':167 'micropayment email' 'multipl':116 'network':89 'no-api-key' 'offer':115 'openapi':196 'oper':68,111 'page':181 'paramet':225 'path':57,220 'pay':2,20 'pay-per-cal':1,19 'pay-per-call email' 'pay-per-request' 'payment':52,83 'per':3,21,100,133,164 'per-cal':163 'platform':114 'post':148 'premium':43,79 'price':129,178 'prompt':188 'protocol':53 'provid':41,110 'pure':161 'rate':154 'readm':180 'relat':46,67 'request':101,134,149 'request/response':199 'requir':18,36 'resourc':56 'retriev':63 'return':183,210 'schema':197 'settl':85 'spars':173 'specif':55 'substant':191 'success':139 'suggest':59 'though':69 'unconfirm':229 'uniform':130 'unit':105 'usdc':14,32,91,166 'usdc-micropayment' 'use':90 'util':127 'via':9,27,49 'wallet':187 'x402':10,28,51,136 'x402 email endpoint' 'x402-payment'","prices":[{"id":"c59d3f8b-e9e2-4657-b86b-5c4b0befbf7e","listingId":"ef9ba0fc-b789-49c2-b275-6ac8b04496d3","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/90","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:13.039Z"}],"sources":[{"listingId":"ef9ba0fc-b789-49c2-b275-6ac8b04496d3","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/90","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:13.039Z","lastSeenAt":"2026-04-22T02:31:51.383Z"}],"details":{"listingId":"ef9ba0fc-b789-49c2-b275-6ac8b04496d3","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/90 \\\n  -H \"Content-Type: application/json\" \\\n  -H \"X-PAYMENT: <x402-payment-header>\"","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"Endpoint returns HTTP 402 with x402 challenge on POST, confirming it is live","source_url":"https://lowpaymentfee.com/api/v1/emails/90"},{"claim":"Payment is 20,000 base units of USDC (6 decimals = $0.02) on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/90"},{"claim":"USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","source_url":"https://lowpaymentfee.com/api/v1/emails/90"},{"claim":"Platform advertises $0.02/request, no API keys, no rate limits, instant access on Base","source_url":"https://lowpaymentfee.com"},{"claim":"Docs, API, pricing, and README pages all show only 'Connect wallet' with no substantive content","source_url":"https://lowpaymentfee.com/docs"}],"useCases":["Retrieving email data or metadata via a single paid API call","Integrating email functionality into agent workflows without managing API keys","Making one-off email-related queries settled in USDC on Base"],"bestFor":["Developers wanting keyless, pay-per-use email API access","AI agents that can settle x402 micropayments on Base","Prototyping email integrations without subscription commitments"],"notFor":["Production email workflows requiring documented request/response schemas","High-volume email operations where per-call pricing adds up","Users who need detailed API documentation before integrating"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:19.876Z"},"updatedAt":"2026-04-22T02:31:51.383Z"}}