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 (specifically for transaction ID 69) 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, settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/69/receipt` accepts POST requests and returns JSON. Payment is handled via the x402 protocol: callers must include an `X-PAYMENT` header with a valid payment proof. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
The platform markets itself as requiring no API keys, no rate limits, and no commitments — just per-request micropayments. However, 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 explanation of what data the receipt endpoint actually returns. The broader site lists many endpoints across categories (sentiment analysis, summarization, embeddings, price feeds, geocoding, etc.), but without documentation it is impossible to verify what any of them actually do.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction 69 via micropayment
- —Demonstrating x402 protocol integration for pay-per-request APIs
- —Agent-driven programmatic access to paid data endpoints without API keys
Fit
Best for
- —Developers experimenting with x402 protocol payments
- —Agents that need keyless, pay-per-call API access on Base
- —Testing micropayment flows with USDC on Base
Not for
- —Production workloads requiring documented request/response schemas
- —Users needing bulk or subscription-based access at lower per-unit cost
- —Anyone needing transaction receipts for arbitrary transaction IDs (this endpoint is hardcoded to ID 69)
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/69/receipt \
-H "X-PAYMENT: <x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no documentation of request parameters or response schema, and the docs/pricing/README pages are all empty. The endpoint path is specific to a single transaction ID with no explanation of what it returns.
Warnings
- —No OpenAPI spec or schema documentation available
- —All documentation pages (/docs, /api, /pricing, /README) render only 'Connect wallet' with no content
- —The endpoint is hardcoded to transaction ID 69 — unclear if other IDs are supported or what the receipt contains
- —No request body schema or response schema documented anywhere
- —The platform lists many endpoints but none have verifiable documentation
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/69/receipt
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/69/receipt
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com