x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides a transaction receipt resource (transaction ID 61) behind an x402 paywall. It is part of a broader platform that advertises multiple API categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/61/receipt` accepts POST requests and returns `application/json`. Payment is handled via the x402 protocol: callers receive a 402 challenge specifying the USDC asset contract on Base (`0x8335…`), and must attach an `X-PAYMENT` header with a valid payment proof. The max amount required is 20,000 base units of USDC (6 decimals), which equals $0.02 per call. No API keys or rate limits are advertised; access is purely pay-per-use.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema beyond the x402 challenge's `outputSchema`, and no explanation of what the receipt payload actually contains. The platform appears to be a demonstration or early-stage x402 showcase rather than a mature production API.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction 61 via a single paid API call
- —Demonstrating x402 protocol integration for agent-to-agent micropayments
- —Testing USDC-on-Base payment flows in a low-cost environment
Fit
Best for
- —Developers experimenting with x402 protocol payments
- —Agents that need to demonstrate pay-per-call USDC micropayments on Base
- —Testing x402 client libraries against a live endpoint
Not for
- —Production workloads requiring documented request/response schemas
- —Users who need bulk or subscription-based API access
- —Anyone needing endpoints beyond a single transaction receipt
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/61/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with valid USDC payment proof to receive the receipt.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is effectively nonexistent — every doc page shows only 'Connect wallet'. There is no OpenAPI spec, no request/response examples, and no description of what the receipt payload contains. The endpoint path is specific to a single transaction ID (61), making its general utility unclear.
Warnings
- —Documentation pages (/docs, /pricing, /api, /README) are all empty beyond a 'Connect wallet' prompt
- —No OpenAPI or schema describing request parameters or response body
- —Endpoint is scoped to a single transaction ID (61) — unclear if this is a demo or production resource
- —No information on what the receipt payload actually contains
- —Platform appears to be an early-stage or demonstration x402 showcase
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/61/receipt
- —The platform advertises $0.02 per request across all API categories with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/61/receipt