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 209) behind an x402 paywall. It is part of a broader platform that offers a variety of pay-per-request APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per call and settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/209/receipt` accepts POST requests and returns an `application/json` response. Payment is handled via the x402 protocol: callers receive a 402 challenge containing the payment terms (asset, amount, payTo address), construct an on-chain USDC payment on Base, and include the payment proof in the `X-PAYMENT` header to unlock the response. The max amount required is 20,000 base units of USDC (6 decimals), which equals $0.02. No API keys, rate limits, or subscriptions are needed — access is purely pay-per-request.
The platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, and more, all at the same $0.02 price point. However, documentation beyond the landing page is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction 209 via a single micropayment
- —Demonstrating x402 protocol integration for pay-per-request APIs
- —Programmatic access to receipts without API key management
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC payments on Base L2
- —Use cases requiring keyless, pay-as-you-go API access
Not for
- —Users needing detailed API documentation or OpenAPI specs before integrating
- —High-volume batch retrieval where per-request micropayments add up
- —Users without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/209/receipt
# Returns 402 with x402 challenge. Include X-PAYMENT header with USDC payment proof on Base to unlock the receipt.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The docs/pricing/API pages are all blank beyond a wallet connect prompt. The specific purpose of this particular receipt endpoint is unclear beyond its URL path.
Warnings
- —No OpenAPI spec or request/response schema available
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no content
- —The specific data returned by /api/v1/transactions/209/receipt is undocumented — unclear what 'transaction 209' refers to
- —The broader platform lists many endpoints 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/209/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 offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/209/receipt