Pay-per-call API key generation on Base via x402 — $0.02 per request in USDC.
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 utilities. All endpoints are priced at $0.02 per request, paid in USDC on the Base network with no API keys, rate limits, or commitments required. The x402 payment challenge is returned as a standard 402 response, and callers settle directly on-chain.
The specific endpoint at `/api/v1/apikeys/13` is listed as "Premium API Access." Its exact functionality is not well-documented beyond the title — the crawled docs, pricing, and README pages all returned only a "Connect wallet" stub with no additional detail. The broader platform advertises endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point.
The x402 challenge for this endpoint specifies a `maxAmountRequired` of 20000 base units of USDC (contract `0x8335…2913` on Base, 6 decimals), which equals $0.02. Payment is made via the "exact" scheme to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
Capabilities
Use cases
- —Acquiring API access tokens via on-chain micropayment
- —Programmatic pay-per-use access to a multi-category API platform
- —Agent-driven API consumption without pre-registration or API keys
Fit
Best for
- —Agents or scripts that need instant, keyless API access paid per call
- —Developers who want to avoid subscription commitments
- —On-chain payment workflows on Base using USDC
Not for
- —Users who need detailed documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Users without a Base-compatible wallet or USDC holdings
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/apikeys/13 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but documentation is essentially absent — docs, pricing, README, and API pages all return only a 'Connect wallet' stub. There is no OpenAPI spec, no request/response schema, and the purpose of the specific /apikeys/13 endpoint is unclear beyond its title. Pricing is clear from the challenge and landing page.
Warnings
- —Documentation pages (/docs, /pricing, /README, /api) are all stubs showing only 'Connect wallet' — no usable docs available.
- —The exact functionality of /api/v1/apikeys/13 ('Premium API Access') is undocumented; it is unclear what the endpoint returns or what input it expects beyond a POST with payment.
- —No OpenAPI spec or request/response schema is provided.
- —The broader platform lists many endpoints (AI, finance, utils) but none have documented schemas or example payloads.
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or commitmentshttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units USDC on Base (equals $0.02)https://lowpaymentfee.com/api/v1/apikeys/13
- —Payment asset is USDC at contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/apikeys/13
- —Platform offers endpoints across data & analytics, AI & ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com