Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/payments/30` is labeled "Premium API Access" and charges up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an x402 payment header to each request.
The broader platform offers endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All listed endpoints share the same $0.02/request pricing.
This particular endpoint (`/api/v1/payments/30`) is live and returns a valid 402 challenge. However, the crawled documentation pages (docs, pricing, API, README) all returned only a "Connect wallet" prompt with no substantive content, so the actual request/response schemas, parameter details, and concrete behavior of this endpoint are unknown. The endpoint accepts POST requests and returns `application/json`.
Capabilities
Use cases
- —Programmatic access to a premium API endpoint with per-call USDC micropayments
- —Agent-driven workflows that need keyless, pay-as-you-go API access on Base
- —Testing x402 protocol integrations with a low-cost live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —AI agents that need keyless API access settled in USDC on Base
- —Low-volume, pay-per-use API consumption without subscriptions
Not for
- —Users who need detailed API documentation or well-defined schemas before integrating
- —High-volume consumers who prefer flat-rate or subscription pricing
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/30 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, all documentation pages returned only 'Connect wallet' with no usable content — there is no OpenAPI schema, no request/response examples, and no description of what 'Premium API Access' actually returns. The listing is effectively a stub.
Warnings
- —No documentation available — all doc/pricing/API/README pages returned only 'Connect wallet' with no content.
- —The actual functionality behind 'Premium API Access' at /api/v1/payments/30 is completely undocumented; request parameters and response format are unknown.
- —No OpenAPI schema or output schema beyond basic HTTP method metadata.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/payments/30
- —All listed endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/30