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. The site hosts a broad catalog of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, settled in USDC on the Base network.
The specific endpoint `/api/v1/keys/98` is listed as "Premium API Access" and accepts POST requests. The x402 challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme with a 300-second timeout. No API keys or rate limits are required — callers simply attach the X-PAYMENT header with a valid x402 payment proof.
Documentation is minimal: the site's landing page lists available endpoints and pricing but provides no request/response schemas, parameter descriptions, or usage examples. The `/api`, `/pricing`, and `/README` pages all resolve to a "Connect wallet" prompt with no additional content. The exact functionality behind `/api/v1/keys/98` (labeled "Premium API Access") is unclear — it may provide an API key or access token, but this is not documented.
Capabilities
Use cases
- —Acquiring premium API access or keys via a single micropayment
- —Agent-driven pay-per-call API consumption without pre-registration
- —Programmatic access to a suite of data, AI, finance, and utility endpoints
Fit
Best for
- —AI agents needing instant, keyless API access via crypto micropayments
- —Developers who want pay-as-you-go pricing with no subscription commitments
- —x402-compatible clients on the Base network
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk/subscription pricing
- —Users without USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/98 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02 USDC on Base), but there is no documentation of request parameters, response schema, or what "Premium API Access" actually returns. The /api, /pricing, and /README pages are empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No request or response schema available — the exact functionality of /api/v1/keys/98 is undocumented
- —All documentation pages (/api, /pricing, /README) return only a 'Connect wallet' prompt with no useful content
- —The purpose of 'Premium API Access' is ambiguous — it may issue API keys or tokens but this is unconfirmed
Citations
- —The site lists APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categories, all priced at $0.02/requesthttps://lowpaymentfee.com
- —Pricing is $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge shows maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/keys/98