x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a transaction receipt (resource ID 89) behind an x402 paywall. The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/Web3 data (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, settled in USDC on the Base network via the x402 protocol — no API keys, no rate limits, no subscriptions.
The specific endpoint probed (`/api/v1/transactions/89/receipt`) returns a valid x402 challenge (HTTP 402) requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to $0.02 per call, consistent with the site's advertised pricing. Payment is made via the `exact` scheme with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
Documentation is extremely thin — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available. The purpose of this particular receipt endpoint and the shape of its response are not documented, making it difficult to know exactly what data is returned without paying for a call.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction ID 89 via a single paid API call
- —Demonstrating x402 protocol payment flows on Base with USDC
- —Integrating pay-per-request APIs without managing API keys or subscriptions
Fit
Best for
- —Developers experimenting with x402 protocol payments
- —Agents that need on-demand paid API access without pre-registration
- —Use cases requiring low-cost per-call pricing ($0.02) settled on-chain
Not for
- —Users needing detailed API documentation or response schemas before purchasing
- —High-volume batch processing where per-call fees add up quickly
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/89/receipt
# Returns HTTP 402 with x402 challenge.
# Include X-PAYMENT header with a valid x402 payment proof to receive the receipt.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing, but there is no documentation, no OpenAPI spec, no request/response schema, and no examples. The purpose of this specific receipt endpoint is opaque. The broader site lists many endpoints but provides zero docs beyond a landing page.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README all show only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose and response format of /api/v1/transactions/89/receipt is undocumented
- —It is unclear whether the broader suite of advertised endpoints (AI, analytics, finance, utils) are actually functional
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/89/receipt
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform advertises APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs