Pay-per-call API platform on Base via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and utility services. All endpoints are priced at $0.02 per request, paid in USDC on the Base network. The x402 protocol means there are no API keys, no accounts, and no rate limits — callers simply attach an X-PAYMENT header with a valid payment proof to each request.
The specific endpoint at `/api/v1/payments/37` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USDC, i.e., $0.02) on Base. The platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, and more — all at the same $0.02 price point.
Documentation is extremely sparse. The crawled docs, API, pricing, and README pages all returned only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed descriptions of what each endpoint actually returns. The endpoint is live and responds with a valid x402 challenge, but without documentation it is unclear what payload to send or what response to expect from this particular "Premium API Access" endpoint.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without managing API keys
- —Fetching real-time crypto prices, gas estimates, and exchange rates on a per-call basis
- —Running geocoding, validation, or data conversion tasks with instant pay-per-use billing
- —Exporting analytics data or generating insights reports without subscription commitments
Fit
Best for
- —Developers who want zero-friction, keyless API access via crypto micropayments
- —Agents and bots that need programmatic pay-per-call access to diverse utility endpoints
- —Projects already operating on the Base network with USDC
Not for
- —Teams requiring detailed API documentation, SLAs, or guaranteed uptime
- —High-volume users who would benefit from bulk pricing or subscription plans
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/37 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base at $0.02/request. However, documentation is essentially nonexistent — all doc pages return only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and the purpose of this specific '/api/v1/payments/37' endpoint beyond 'Premium API Access' is unknown. The listing is effectively a stub.
Warnings
- —No documentation available — all doc/pricing/README pages return only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format
- —The specific purpose of /api/v1/payments/37 ('Premium API Access') is unclear and may be a generic or placeholder endpoint
- —No request or response examples could be sourced
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0.02 USDC) on Basehttps://lowpaymentfee.com/api/v1/payments/37
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/37