Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. It is one of many endpoints offered by the lowpaymentfee.com platform, which hosts a collection of pay-per-request APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. 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 `/api/v1/payments/337` is labeled "Premium API Access" in the x402 challenge but its exact functionality is not documented beyond that label. The x402 challenge confirms it is live, accepts POST requests, and requires a payment of up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) to the address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3`. The response MIME type is `application/json`.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI schema, no request/response examples, and no detailed description of what this particular endpoint returns. The platform's landing page lists sibling endpoints for analytics, AI inference, finance data, and utilities, all at the same $0.02 price point, but the `/api/v1/payments/337` endpoint does not appear in that public catalog. Users should be aware that the actual behavior of this endpoint is unclear from available documentation.
Capabilities
Use cases
- —Accessing a premium API endpoint with per-call USDC micropayments on Base
- —Integrating x402-compatible payment flows into agent workflows
- —Testing x402 protocol payment challenges against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing pay-per-call API access without API keys
- —Users who want to pay in USDC on Base with no subscription
Not for
- —Users who need detailed API documentation or schemas before integrating
- —Anyone requiring non-crypto payment methods
- —Production workloads requiring guaranteed SLAs or support
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/337 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no request/response examples, and the specific functionality of /api/v1/payments/337 is undescribed. The docs pages are empty beyond a wallet connect prompt. This is effectively a stub listing.
Warnings
- —The exact functionality of /api/v1/payments/337 is not documented — 'Premium API Access' is the only description available.
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no usable content.
- —This endpoint does not appear in the platform's public API catalog on the landing page.
- —No OpenAPI schema, request format, or response examples are available.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/payments/337
- —All endpoints on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/337