x402-gated transaction receipt endpoint on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides a transaction receipt resource (specifically for transaction ID 15) behind an x402 paywall. The broader lowpaymentfee.com platform advertises a suite of pay-per-request APIs spanning data & analytics, AI & machine learning (sentiment analysis, summarization, classification, embeddings), finance & Web3 (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 minimum commitments.
The specific probed endpoint (`/api/v1/transactions/15/receipt`) returns a valid x402 challenge 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 x402 "exact" scheme to the specified payTo address. The endpoint accepts POST requests and returns application/json.
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 usage examples available. The purpose and payload of a "transaction receipt" are not documented, so the actual data returned after payment is unknown.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction ID 15 via micropayment
- —Demonstrating x402 protocol payment flows on Base
- —Integrating pay-per-call APIs without API key management
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that need keyless, pay-per-call API access on Base
- —Use cases requiring low-friction micropayment-gated data retrieval
Not for
- —Production workloads requiring documented request/response schemas
- —Bulk or high-volume data retrieval where per-call pricing is inefficient
- —Users who need traditional API key authentication and rate limit guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/15/receipt
# Returns 402 with x402 challenge; attach X-PAYMENT header with USDC payment proof to access the resource.Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no documented request/response schema, no examples, and the docs pages are empty. The specific purpose of a 'transaction receipt' for ID 15 is unexplained, making this effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or schema definition found for request or response payloads.
- —The endpoint is scoped to a single transaction ID (15); it is unclear whether this is a demo or a general-purpose resource.
- —The actual data returned after successful payment is unknown.
Citations
- —The platform advertises $0.02 per request pricing with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The x402 challenge requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base.https://lowpaymentfee.com/api/v1/transactions/15/receipt
- —The platform lists APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categories.https://lowpaymentfee.com