x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a specific transaction receipt (transaction ID 286) 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.
The specific endpoint probed (/api/v1/transactions/286/receipt) returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this equates to $0.02 per call — consistent with the site's advertised pricing. Payment is made via the x402 "exact" scheme, with a 300-second timeout. No API keys or rate limits are required; access is granted purely through on-chain payment.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what the receipt payload actually contains. The endpoint is live and responding with a proper 402 challenge, but the lack of documentation makes it difficult to know what data is returned or what input parameters (if any) the POST body should contain.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction 286 via programmatic payment
- —Demonstrating x402 protocol integration for pay-per-request APIs
- —Accessing financial or transactional data without API key registration
Fit
Best for
- —Developers experimenting with x402 protocol payments
- —Agents that can settle USDC payments on Base for per-call API access
- —Use cases requiring keyless, permissionless API access
Not for
- —Production workloads requiring documented request/response schemas
- —Users without USDC on the Base network
- —Bulk data retrieval where per-request pricing is cost-prohibitive
Quick start
# 1. Send POST to get the 402 challenge
curl -X POST https://lowpaymentfee.com/api/v1/transactions/286/receipt
# Returns 402 with x402 payment challenge
# 2. Construct X-PAYMENT header with USDC payment proof on Base
# 3. Resend POST with X-PAYMENT header to receive the receiptEndpoint
Quality
The endpoint is live and returns a valid x402 challenge consistent with advertised $0.02 USDC pricing on Base. However, there is no OpenAPI spec, no documentation of request parameters or response schema, and no examples. The docs pages are empty. The endpoint path suggests a single fixed resource (transaction 286) rather than a general-purpose API, which limits utility.
Warnings
- —No OpenAPI spec or schema documentation available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The endpoint targets a specific transaction ID (286) — unclear if this is a demo or a real resource
- —No request body schema or response schema documented anywhere
- —The broader platform advertises many API categories (AI, analytics, finance, utilities) but none have documented schemas
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, on Base networkhttps://lowpaymentfee.com
- —Platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base with 300s timeouthttps://lowpaymentfee.com/api/v1/transactions/286/receipt