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 161) 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, with no API keys, no rate limits, and no commitments required.
The specific endpoint probed (/api/v1/transactions/161/receipt) returns a valid x402 challenge (HTTP 402) requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) via the "exact" payment scheme on Base. The payment is directed to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
Documentation is extremely sparse — the /docs, /pricing, /api, 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 examples of what the receipt payload actually contains. The platform appears to be a demonstration or early-stage x402 marketplace rather than a mature production API.
Capabilities
Use cases
- —Retrieving a transaction receipt for a specific transaction ID via micropayment
- —Demonstrating x402 protocol payment flows on Base
- —Agent-driven pay-per-use API consumption without API keys
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless, pay-per-call API access on Base
- —Testing USDC micropayment integrations
Not for
- —Production workloads requiring documented request/response schemas
- —Bulk data retrieval where per-request fees add up quickly
- —Users who need traditional API key authentication and rate limit guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/161/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with signed USDC payment to access the receipt.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is effectively nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no examples of what the receipt payload contains. The endpoint path suggests a single static resource (transaction 161) rather than a general-purpose API. The broader platform lists many endpoints but none are documented beyond a name and price.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific endpoint path (/api/v1/transactions/161/receipt) appears to reference a single hardcoded transaction ID; unclear if this is parameterized
- —No examples of actual response payloads; unknown what data the receipt contains
- —Platform may be a demo or early-stage project given the lack of documentation
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —x402 challenge requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/161/receipt
- —Payment directed to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300-second timeouthttps://lowpaymentfee.com/api/v1/transactions/161/receipt