Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
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/transactions/102` is labeled "Premium API Access" and requires a payment of up to 20,000 base units of USDC (0.02 USD) per call. The platform advertises no API keys, no rate limits, and instant access — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
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 endpoints are listed at the same $0.02/request price point.
However, the documentation pages (docs, pricing, README) all resolve to a minimal "Connect wallet" stub with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint is live and returns a valid 402 challenge, but without documentation it is unclear what request body the `/api/v1/transactions/102` endpoint expects or what response it returns. The "Premium API Access" label is generic and does not describe the actual functionality of this specific endpoint.
Capabilities
Use cases
- —Accessing paid API endpoints without traditional API key registration
- —Making one-off API calls settled in USDC on Base L2
- —Agent-driven workflows that need instant, keyless API access
Fit
Best for
- —Developers who want to pay per request without subscriptions
- —AI agents with x402-compatible wallets on Base network
- —Quick prototyping without account signup
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where subscription pricing would be cheaper
- —Users without a Base-network USDC wallet
Quick start
# The endpoint returns 402 with an x402 challenge.
# Use an x402-compatible client to auto-negotiate payment.
curl -X POST https://lowpaymentfee.com/api/v1/transactions/102 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect stub, and the endpoint name 'Premium API Access' is entirely generic with no indication of what it actually does. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — all doc pages return only 'Connect wallet'
- —The specific functionality of /api/v1/transactions/102 ('Premium API Access') is undocumented and unclear
- —No example request or response payloads are available anywhere in the crawled material
- —The platform lists many endpoints but none have documented input/output schemas
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x8335…) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/102
- —All 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
- —Documentation pages resolve to minimal 'Connect wallet' stubshttps://lowpaymentfee.com/docs