Pay-per-call API platform on Base (USDC) covering analytics, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints settled in USDC on the Base network. The specific endpoint at `/api/v1/payments/311` is listed as "Premium API Access" and returns a standard x402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02) per call. No API keys or rate limits are advertised; callers simply attach an X-PAYMENT header to each request.
The platform organizes its endpoints into 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 listed endpoints share the same $0.02 per-request pricing.
Documentation beyond the landing page is extremely thin — the /docs, /pricing, /api, 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 usage examples available from the crawl. The endpoint is confirmed live (402 challenge captured), but the lack of documentation makes it difficult to know what request body to send or what response to expect for this particular endpoint.
Capabilities
Use cases
- —Accessing AI inference (sentiment, summarization, classification, embeddings) without managing API keys or subscriptions
- —Fetching real-time financial data such as token quotes, gas estimates, and exchange rates on a per-call basis
- —Running analytics queries and data exports with instant crypto-settled payments
- —Geocoding, validation, and data conversion via utility endpoints
Fit
Best for
- —Agents or bots that need keyless, pay-as-you-go API access settled on-chain
- —Developers prototyping with multiple API categories without committing to subscriptions
- —Web3-native applications that prefer USDC micropayments over traditional billing
Not for
- —Users who need detailed API documentation, schemas, or guaranteed SLAs before integrating
- —High-volume production workloads where $0.02/request adds up and bulk pricing is preferred
- —Teams that cannot transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/311 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and the landing page provides a catalog overview with pricing. However, there is no OpenAPI spec, no request/response schema, no documentation, and no examples — the docs pages all render only 'Connect wallet'. The specific purpose of /api/v1/payments/311 beyond 'Premium API Access' is unknown.
Warnings
- —No OpenAPI or schema documentation available; all doc pages return only 'Connect wallet'
- —The specific functionality of /api/v1/payments/311 ('Premium API Access') is undocumented — it is unclear what request body it expects or what it returns
- —No response examples or error codes documented anywhere in the crawl
- —The platform lists many endpoint categories but none have detailed specs
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/payments/311
- —All listed endpoints share $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints in four categories: Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/payments/311