x402-gated transaction receipt endpoint on Base, paying $0.02 in USDC per request.
What it does
This endpoint at lowpaymentfee.com provides a transaction receipt resource (transaction ID 219) behind an x402 paywall. It is part of a broader platform that offers a variety of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and utility services — all priced at $0.02 per request, settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/219/receipt` accepts POST requests and returns JSON. Payment is handled via the x402 protocol: callers must include an `X-PAYMENT` header with a valid payment proof. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform markets itself as requiring no API keys, no rate limits, and no commitments — just per-request micropayments. However, documentation beyond the landing page is essentially empty (all sub-pages only show a "Connect wallet" prompt), so the exact schema of request bodies and response payloads for this and other endpoints is undocumented. The endpoint is confirmed live via a valid 402 challenge response.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction 219 via a single micropayment
- —Demonstrating x402 protocol integration for pay-per-call services
- —Programmatic access to receipt data without API key management
Fit
Best for
- —Developers experimenting with x402 micropayment protocols
- —Agents that need on-demand receipt retrieval without subscription overhead
- —Applications already holding USDC on Base that want frictionless API access
Not for
- —Users needing bulk or batch transaction receipt retrieval (no documented batch endpoint)
- —Anyone requiring detailed API documentation or guaranteed SLAs (docs are essentially empty)
- —Use cases requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/219/receipt \
-H "X-PAYMENT: <x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI schema, no documented request/response format, no examples, and all documentation pages are empty stubs. The specific purpose of this receipt endpoint is unclear beyond its URL path.
Warnings
- —Documentation pages (/docs, /api, /pricing, /README) are all empty — only showing 'Connect wallet'
- —No request or response schema is documented for this or any endpoint on the platform
- —The endpoint path references a specific transaction ID (219); it is unclear whether this is a generic pattern or a single fixed resource
- —The broader platform lists many API categories (AI, finance, analytics, etc.) but none have documented schemas or examples
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/219/receipt
- —All APIs on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/219/receipt