{"id":"0ff9968d-cf39-4ede-b78b-e43c3d7bfc3d","shortId":"cqeGMh","kind":"x402","title":"Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.","tagline":"Pay-per-call API platform on Base (USDC) offering data, AI, finance, and utility endpoints at $0.02/request.","description":"lowpaymentfee.com is an x402-enabled API platform that provides a variety of endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, payable in USDC on the Base network via the x402 protocol.\n\nThe specific endpoint at `/api/v1/invoices/27` is listed as \"Premium API Access\" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme with a 300-second timeout. No API keys or rate limits are advertised; access is instant upon payment.\n\nDocumentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a \"Connect wallet\" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed documentation for any endpoint. The exact functionality behind the `/api/v1/invoices/27` path is unclear; the name \"Premium API Access\" does not describe a specific capability. The platform appears to be a demonstration or early-stage deployment of x402 pay-per-call APIs.","tags":[],"capabilities":["x402-payment","usdc-base","pay-per-request","data-analytics","ai-sentiment","ai-summarization","ai-classification","ai-embeddings","finance-prices","exchange-rates","crypto-gas","geocoding","validation"],"categories":["api-platform","llm","finance","geo"],"synonyms":["low payment fee","x402 api","pay per call api","usdc api","base network api","micropayment api","402 payment api"],"warnings":["Documentation pages (/docs, /pricing, /api, /README) all render only 'Connect wallet' with no usable content","No OpenAPI or JSON schema available for any endpoint","The specific functionality of /api/v1/invoices/27 ('Premium API Access') is not documented — it may be a generic or demo endpoint","No request body schema or response format is documented anywhere","Platform may be early-stage or a demonstration site"],"endpointUrl":"https://lowpaymentfee.com/api/v1/invoices/27","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/invoices/27","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.350","qualityRationale":"The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02. However, there is no OpenAPI schema, no request/response examples, and all documentation pages are empty stubs. The specific purpose of /api/v1/invoices/27 is unclear beyond the generic label 'Premium API 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'x402-payment'","prices":[{"id":"dd70ca35-a343-4bd4-8d7d-b616c24bcd62","listingId":"0ff9968d-cf39-4ede-b78b-e43c3d7bfc3d","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/invoices/27","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T18:38:36.349Z"}],"sources":[{"listingId":"0ff9968d-cf39-4ede-b78b-e43c3d7bfc3d","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/invoices/27","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T18:38:36.349Z","lastSeenAt":"2026-04-23T12:30:48.108Z"}],"details":{"listingId":"0ff9968d-cf39-4ede-b78b-e43c3d7bfc3d","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/invoices/27 \\\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":"All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base network","source_url":"https://lowpaymentfee.com"},{"claim":"x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02","source_url":"https://lowpaymentfee.com/api/v1/invoices/27"},{"claim":"Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories","source_url":"https://lowpaymentfee.com"}],"useCases":["Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API keys","Fetching real-time financial data like token quotes, exchange rates, and gas estimates","Running utility operations like geocoding, validation, and data conversion on a per-call basis","Demonstrating or testing x402 payment protocol integrations"],"bestFor":["Developers experimenting with x402 pay-per-call protocols","Agents needing low-cost, keyless API access on Base","Projects requiring diverse lightweight API endpoints without subscription commitments"],"notFor":["Production workloads requiring documented SLAs and detailed API schemas","Users who need high-throughput or bulk data access at volume discounts","Anyone without a Base-compatible USDC wallet"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:14:41.349Z"},"updatedAt":"2026-04-23T12:30:48.108Z"}}