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 86) 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/86/receipt` accepts POST requests and returns `application/json`. Payment is handled via the x402 protocol: callers receive a 402 challenge specifying the USDC asset on Base (contract `0x8335…2913`), 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 thin — the docs, pricing, API, and README pages all render only a "Connect wallet" prompt with no substantive 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 86 via a micropayment
- —Demonstrating x402 protocol payment flows on Base
- —Integrating pay-per-call USDC-settled endpoints into agent workflows
Fit
Best for
- —Developers experimenting with x402 protocol integrations
- —Agents that need to make micropayment-gated API calls on Base
- —Testing USDC-settled per-request payment flows
Not for
- —Production workloads requiring documented request/response schemas
- —Users who need free or subscription-based API access
- —Retrieving arbitrary transaction receipts (endpoint is scoped to transaction 86)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/86/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with valid USDC payment proof to proceed.Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but documentation is essentially 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 is scoped to a single transaction ID (86), which limits general utility.
Warnings
- —Documentation pages (docs, pricing, API, README) all render only 'Connect wallet' with no substantive content.
- —No OpenAPI or schema describing the receipt response payload.
- —Endpoint is hardcoded to transaction ID 86 — unclear if other transaction IDs are available or what the receipt contains.
- —Platform appears to be a demo or early-stage project; production readiness is uncertain.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/86/receipt
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform lists categories including Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/86/receipt