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 (transaction ID 14) behind an x402 paywall. It is part of a broader platform that advertises multiple API categories including data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities — all priced at $0.02 per request and settled in USDC on the Base network.
The specific endpoint `/api/v1/transactions/14/receipt` accepts POST requests and returns `application/json`. Payment is handled via the x402 protocol: callers receive a 402 challenge containing the accepted payment scheme (exact), the USDC asset contract on Base (`0x8335…`), and a maximum amount of 20,000 base units. Since USDC uses 6 decimals, this translates to $0.02 per call — consistent with the site's advertised flat pricing. No API keys or rate limits are required; access is granted immediately upon payment.
Documentation on the site is extremely thin — 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 endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to know what data is returned or what inputs (if any) the POST body expects.
Capabilities
Use cases
- —Retrieving a transaction receipt for transaction ID 14 via a micropayment
- —Demonstrating x402 protocol integration for pay-per-call APIs
- —Programmatic access to receipt data without API key management
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can settle USDC payments on Base
- —Use cases requiring keyless, pay-per-request API access
Not for
- —Users needing detailed API documentation or schema guarantees before integrating
- —Bulk retrieval of many different transaction receipts (only transaction 14 is exposed at this URL)
- —Non-crypto users who cannot settle USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/14/receipt
# Returns 402 with x402 challenge; include X-PAYMENT header with valid USDC payment to receive the receipt.Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples of what the receipt payload contains. The endpoint is for a single hardcoded transaction ID with no explanation of its purpose.
Warnings
- —No documentation available — docs, pricing, API, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request body or response format
- —Endpoint is for a single transaction ID (14); unclear if other transaction IDs are available
- —Purpose and contents of the 'receipt' resource are undocumented
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/14/receipt
- —The platform advertises $0.02 per request across all APIs with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/transactions/14/receipt