{"id":"6ee71708-30b8-4fd6-8f9c-14f941b5b773","shortId":"ZAvEsM","kind":"x402","title":"Pay-per-call notification endpoint on Base via x402 — $0.02 per request in USDC.","tagline":"Pay-per-call notification endpoint on Base via x402 — $0.02 per request in USDC.","description":"This endpoint at `/api/v1/notifications/53` is part of the lowpaymentfee.com platform, which offers a suite of pay-per-request APIs spanning data analytics, AI/ML inference, finance, and infrastructure utilities. All endpoints use the x402 protocol on the Base network, accepting USDC payments with no API keys, no rate limits, and no subscriptions required.\n\nThe specific endpoint probed (`/api/v1/notifications/53`) is listed under the provider's umbrella as \"Premium API Access.\" The x402 challenge confirms it is live and accepts exact-scheme payments of up to 20,000 base units of USDC (0x8335…) on Base, which equals $0.02 per request (USDC uses 6 decimals). The endpoint accepts POST requests and returns `application/json`. No detailed input or output schema is documented beyond the x402 challenge metadata.\n\nThe broader platform advertises 16+ endpoints across categories like sentiment analysis, text summarization, embeddings, price feeds, gas estimates, geocoding, and more — all at the same $0.02/request price point. Documentation is minimal: the /api, /pricing, and /README pages all resolve to a wallet-connect prompt with no further content. Without OpenAPI specs or example payloads, the exact request body format and response structure for this notifications endpoint remain unknown.","tags":[],"capabilities":["x402-payment","usdc-base","pay-per-request","notifications","json-response","no-api-key","no-rate-limit"],"categories":["notifications","infrastructure"],"synonyms":["premium API access","notification API","x402 notification","pay-per-call API","Base USDC API","lowpaymentfee","micropayment API"],"warnings":["No OpenAPI or schema documentation available for this endpoint","The exact purpose and payload format of /api/v1/notifications/53 is undocumented","All ancillary pages (/api, /pricing, /README) return only a wallet-connect prompt with no useful content","The endpoint name 'Premium API Access' is generic and does not describe functionality"],"endpointUrl":"https://lowpaymentfee.com/api/v1/notifications/53","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/notifications/53","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 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documented request/response schema, no examples, and the /api, /pricing, and /README pages are empty beyond a wallet-connect prompt. The purpose of 'notifications/53' is entirely opaque — it could be a notification retrieval, trigger, or something else. Effectively a stub 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'/api/v1/notifications/53':34,88 '/pricing':189 '/readme':191 '/request':181 '0.02':11,26,127,180 '000':117 '0x8335':122 '16':159 '20':116 '6':132 'Base USDC API' 'accept':70,108,136 'access':99 'across':161 'advertis':158 'ai/ml':54 'analysi':165 'analyt':53 'api':50,75,98 'application/json':141 'base':8,23,68,118,124 'beyond':150 'bodi':214 'broader':156 'call':4,19 'categori':162 'challeng':102,153 'confirm':103 'connect':199 'content':204 'data':52 'decim':133 'detail':143 'document':149,184 'embed':168 'endpoint':6,21,32,61,86,135,160,222 'equal':126 'estim':172 'exact':110,212 'exact-schem':109 'exampl':209 'feed':170 'financ':56 'format':215 'gas':171 'geocod':173 'infer':55 'infrastructur':58 'input':144 'json-response' 'key':76 'like':163 'limit':79 'list':90 'live':106 'lowpaymentfee' 'lowpaymentfee.com':39 'metadata':154 'micropayment API' 'minim':186 'network':69 'no-api-key' 'no-rate-limit' 'notif':5,20,221 'notification API' 'notifications' 'offer':42 'openapi':206 'output':146 'page':192 'part':36 'pay':2,17,47 'pay-per-cal':1,16 'pay-per-call API' 'pay-per-request':46 'payload':210 'payment':72,112 'per':3,12,18,27,48,128 'platform':40,157 'point':183 'post':137 'premium':97 'premium API access' 'price':169,182 'probe':87 'prompt':200 'protocol':65 'provid':93 'rate':78 'remain':223 'request':13,28,49,129,138,213 'requir':83 'resolv':194 'respons':217 'return':140 'schema':147 'scheme':111 'sentiment':164 'span':51 'spec':207 'specif':85 'structur':218 'subscript':82 'suit':44 'summar':167 'text':166 'umbrella':95 'unit':119 'unknown':224 'usdc':15,30,71,121,130 'usdc-base' 'use':62,131 'util':59 'via':9,24 'wallet':198 'wallet-connect':197 'without':205 'x402':10,25,64,101,152 'x402 notification' 'x402-payment'","prices":[{"id":"2484f38d-1878-4b9d-82e9-da0d5e7ae049","listingId":"6ee71708-30b8-4fd6-8f9c-14f941b5b773","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/notifications/53","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:29.208Z"}],"sources":[{"listingId":"6ee71708-30b8-4fd6-8f9c-14f941b5b773","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/notifications/53","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:29.208Z","lastSeenAt":"2026-04-22T02:32:10.813Z"}],"details":{"listingId":"6ee71708-30b8-4fd6-8f9c-14f941b5b773","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/notifications/53 \\\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":"The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/notifications/53"},{"claim":"USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","source_url":"https://lowpaymentfee.com/api/v1/notifications/53"},{"claim":"All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base","source_url":"https://lowpaymentfee.com"},{"claim":"The platform offers 16+ endpoints across data/analytics, AI/ML, finance/web3, and infrastructure categories","source_url":"https://lowpaymentfee.com"}],"useCases":["Triggering or retrieving notifications via a pay-per-call model without managing API keys","Integrating notification delivery into agent workflows that settle payments on Base","Testing x402 protocol integrations with a low-cost endpoint"],"bestFor":["Developers experimenting with x402 payment-gated APIs","Agents that need simple, keyless, per-call access to notification services","Projects already operating on the Base L2 with USDC"],"notFor":["Users who need detailed API documentation or OpenAPI schemas before integrating","High-volume notification pipelines where per-call pricing adds up quickly","Anyone requiring non-USDC or non-Base payment rails"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:12:56.461Z"},"updatedAt":"2026-04-22T02:32:10.813Z"}}