Pay-per-call API access on Base via x402 — $0.02/request in USDC, no keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure utility categories. All endpoints are priced at $0.02 per request, payable in USDC on the Base network. The x402 protocol means there are no API keys, no sign-ups, and no rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/keys/59` is listed as "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC with 6 decimals = $0.02). Payment is settled on-chain to a specified wallet address using the USDC contract on Base (0x8335…2913). The endpoint accepts POST requests and returns application/json.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02 per-request price point. However, the crawled documentation is extremely thin: the /api, /pricing, and /README pages all returned only a "Connect wallet" prompt with no further detail. There is no OpenAPI schema, no request/response examples, and no documentation describing what inputs each endpoint expects or what outputs it returns. The actual functionality behind this specific endpoint (keys/59) is unclear from the available material.
Capabilities
Use cases
- —Accessing paid API endpoints without sign-up or API key management
- —Making micropayment-gated API calls settled in USDC on Base
- —Agent-driven workflows that need on-demand paid API access without subscriptions
Fit
Best for
- —Developers wanting zero-friction, keyless API access
- —AI agents that can attach x402 payment headers automatically
- —Users who prefer pay-per-use over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume callers who would benefit from bulk pricing or subscriptions
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/59 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts payments. However, there is no OpenAPI schema, no request/response examples, and no meaningful documentation — the /api, /pricing, and /README pages are all blank beyond a wallet-connect prompt. The purpose of the specific '/api/v1/keys/59' endpoint is entirely unclear. This is effectively a stub listing.
Warnings
- —No OpenAPI schema or endpoint documentation available
- —The specific functionality of /api/v1/keys/59 ('Premium API Access') is undocumented and unclear
- —All documentation pages (/api, /pricing, /README) returned only 'Connect wallet' with no content
- —No request or response examples could be found or inferred
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —maxAmountRequired is 20000 base units of USDC (6 decimals) = $0.02, paid on Base networkhttps://lowpaymentfee.com/api/v1/keys/59
- —USDC asset contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/59
- —Platform offers endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com