x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that exposes 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 pay-per-call at $0.02 each, settled in USDC on the Base network via the x402 protocol.
The specific endpoint being listed here — `/api/v1/transactions/36/receipt` — is described as "Premium API Access" and was probed live, returning a valid 402 challenge. Its x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the `exact` scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
Documentation beyond the landing page is extremely thin — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this particular receipt endpoint returns. The platform advertises no API keys, no rate limits, and instant access, but the actual behavior and response format of each endpoint remain undocumented.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API keys
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates
- —Running utility operations such as geocoding, validation, and data conversion on a per-call basis
- —Retrieving transaction receipts or analytics reports with per-request USDC micropayments
Fit
Best for
- —Developers wanting key-free, pay-per-use API access settled in crypto
- —Agents or bots that need programmatic access to diverse utility endpoints via x402
- —Projects on Base network looking for low-cost micropayment-gated services
Not for
- —Users who need detailed API documentation, request/response schemas, or SLA guarantees
- —Applications requiring high-throughput access with predictable flat-rate pricing
- —Non-crypto users who cannot pay in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/36/receipt \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it works. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and the specific purpose of this 'transactions/36/receipt' endpoint is unclear. The docs, pricing, and README pages are all empty beyond a wallet connect prompt.
Warnings
- —No OpenAPI or schema documentation available for any endpoint
- —The /docs, /pricing, /api, and /README pages contain no usable content (only 'Connect wallet')
- —The specific purpose and response format of /api/v1/transactions/36/receipt is undocumented
- —The endpoint path includes a hardcoded ID (36), suggesting it may be a specific resource rather than a general-purpose API
- —No examples of request bodies or response payloads are available anywhere in the crawled material
Citations
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories, all at $0.02/requesthttps://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge shows maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/36/receipt
- —Payment is via exact scheme to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300-second timeouthttps://lowpaymentfee.com/api/v1/transactions/36/receipt