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/35` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — you simply attach an x402 payment header to each request.
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, documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The specific functionality of the `/api/v1/transactions/35` endpoint beyond its title "Premium API Access" is unclear — it could be a transaction lookup, a transaction creation endpoint, or something else entirely. The endpoint is live and responding with a valid x402 challenge, but without documentation it is difficult to know what data to send or what response to expect.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API keys
- —Programmatic pay-as-you-go access to analytics, AI, finance, or utility endpoints
Fit
Best for
- —Developers wanting zero-signup, pay-per-use API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who want bulk pricing or subscription discounts
- —Developers not set up to make USDC payments on the Base network
Quick start
# The endpoint requires an x402 payment header (USDC on Base).
# 1. Send a POST without payment to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/35
# 2. Parse the 402 JSON challenge, construct an X-PAYMENT header
# with a signed USDC transfer of 0.02 USDC, then retry:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/35 \
-H "X-PAYMENT: <signed-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming it accepts $0.02 USDC on Base. However, there is no OpenAPI spec, no documentation beyond a landing page listing, no request/response schemas, and no examples. The specific purpose of /api/v1/transactions/35 is undocumented. This is effectively a stub listing.
Warnings
- —No OpenAPI spec or schema documentation available
- —Docs, API, pricing, and README pages all render only 'Connect wallet' with no content
- —The specific functionality of /api/v1/transactions/35 ('Premium API Access') is undocumented — unclear what it does or what request body it expects
- —No example request or response payloads available anywhere in crawled content
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC ($0.02) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/35
- —The platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categories all at $0.02/requesthttps://lowpaymentfee.com
- —The platform advertises no API keys, no rate limits, instant access, and Base network settlementhttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/35