{"id":"70e2e121-060b-4caf-98fe-adaa8bbcb815","shortId":"rvCWcy","kind":"x402","title":"x402-gated portfolio data endpoint on Base, pay $0.02 per request in USDC.","tagline":"x402-gated portfolio data endpoint on Base, pay $0.02 per request in USDC.","description":"This endpoint at `/api/v1/portfolios/56` is part of the lowpaymentfee.com platform, which offers a collection of x402-protocol pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. The specific `/portfolios/56` resource is listed under \"Premium API Access\" but its exact data payload is not documented in the available crawl material. The platform advertises a flat $0.02 per request across all endpoints.\n\nPayment is handled via the x402 protocol on the Base network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The probe confirms the endpoint is live, returning a 402 challenge with `maxAmountRequired` of 20000 base units, which equals $0.02 (USDC has 6 decimals). The payment scheme is \"exact\" with a 300-second timeout. No API keys or rate limits are advertised — access is granted purely via the x402 payment header.\n\nDocumentation is extremely sparse. The docs, API, pricing, and README pages all render only a \"Connect wallet\" prompt with no additional content. There is no OpenAPI schema, no description of the request body format, and no example of the response payload for this specific endpoint. The endpoint accepts POST requests per the outputSchema. Without further documentation it is unclear what input parameters (if any) are expected or what the portfolio data contains.","tags":[],"capabilities":["x402-payment","per-request-billing","usdc-base","portfolio-data","post-endpoint","no-api-key"],"categories":["finance","data"],"synonyms":["portfolio API","premium API access","x402 portfolio","pay-per-call API","USDC micropayment API","lowpaymentfee","Base network API"],"warnings":["No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content","No OpenAPI or request/response schema provided for this endpoint","The specific data returned by /api/v1/portfolios/56 is undocumented; 'Premium API Access' is the only description","This endpoint path (/portfolios/56) does not appear in the site's own listed API catalog, raising questions about its purpose"],"endpointUrl":"https://lowpaymentfee.com/api/v1/portfolios/56","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/portfolios/56","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 the x402 challenge is well-formed with clear pricing ($0.02 USDC on Base). However, there is no documentation of request/response schemas, no examples, and the docs pages are empty. The purpose of '/portfolios/56' is entirely opaque beyond the generic 'Premium API Access' 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'/portfolios/56':63 '0.02':10,24,89,129 '0x833589fcd6edb6e08f4c7c32d4f71b54bda02913':109 '20000':124 '300':141 '402':119 '6':132 'Base network API' 'USDC micropayment API' 'accept':208 'access':70,152 'across':92 'addit':181 'advertis':86,151 'ai/ml':55 'analyt':54 'api':51,69,145,167 'avail':81 'base':8,22,104,125 'bodi':193 'challeng':120 'collect':42 'confirm':112 'connect':176 'contain':232 'content':182 'contract':108 'crawl':82 'data':5,19,53,74,231 'decim':133 'descript':189 'doc':166 'document':78,161,216 'endpoint':6,20,30,94,114,205,207 'equal':128 'exact':73,138 'exampl':197 'expect':226 'extrem':163 'finance/web3':57 'flat':88 'format':194 'gate':3,17 'grant':154 'handl':97 'header':160 'infer':56 'infrastructur':59 'input':221 'key':146 'limit':149 'list':66 'live':116 'lowpaymentfee' 'lowpaymentfee.com':37 'materi':83 'maxamountrequir':122 'network':105 'no-api-key' 'offer':40 'openapi':186 'outputschema':213 'page':171 'paramet':222 'part':34 'pay':9,23,48 'pay-per-call API' 'pay-per-request':47 'payload':75,201 'payment':95,135,159 'per':11,25,49,90,211 'per-request-billing' 'platform':38,85 'portfolio':4,18,230 'portfolio API' 'portfolio-data' 'post':209 'post-endpoint' 'premium':68 'premium API access' 'price':168 'probe':111 'prompt':178 'protocol':46,101 'pure':155 'rate':148 'readm':170 'render':173 'request':12,26,50,91,192,210 'resourc':64 'respons':200 'return':117 'schema':187 'scheme':136 'second':142 'span':52 'spars':164 'specif':62,204 'timeout':143 'unclear':219 'unit':126 'usdc':14,28,107,130 'usdc-base' 'use':106 'util':60 'via':98,156 'wallet':177 'without':214 'x402':2,16,45,100,158 'x402 portfolio' 'x402-gated':1,15 'x402-payment' 'x402-protocol':44","prices":[{"id":"4c291a33-f87c-4446-a7f7-ed9a9c1650b0","listingId":"70e2e121-060b-4caf-98fe-adaa8bbcb815","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/portfolios/56","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T18:53:06.172Z"}],"sources":[{"listingId":"70e2e121-060b-4caf-98fe-adaa8bbcb815","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/portfolios/56","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T18:53:06.172Z","lastSeenAt":"2026-04-27T21:34:10.175Z"}],"details":{"listingId":"70e2e121-060b-4caf-98fe-adaa8bbcb815","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/portfolios/56 \\\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 in USDC on Base network","source_url":"https://lowpaymentfee.com/api/v1/portfolios/56"},{"claim":"Platform advertises $0.02 per request with no API keys, no rate limits, and instant access","source_url":"https://lowpaymentfee.com"},{"claim":"USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","source_url":"https://lowpaymentfee.com/api/v1/portfolios/56"}],"useCases":["Fetching portfolio data on-demand with per-request USDC micropayments","Integrating pay-per-call financial data into agent workflows without API key management","Accessing gated data endpoints using x402 protocol on Base L2"],"bestFor":["Developers experimenting with x402 pay-per-request protocols","Agents that need keyless, on-demand API access settled in USDC on Base","Low-volume or sporadic data consumers who prefer pay-as-you-go over subscriptions"],"notFor":["Users needing well-documented, schema-validated API contracts","High-volume consumers who need bulk pricing or rate guarantees","Anyone without a Base-compatible USDC wallet"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:59.363Z"},"updatedAt":"2026-04-27T21:34:10.175Z"}}