Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a variety of endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no minimum commitments required.
The specific endpoint at `/api/v1/charges/199` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base). Since USDC uses 6 decimals, this translates to $0.02 per request, consistent with the site's advertised flat pricing. Payment is made via the x402 exact scheme, settling to the specified payTo address with a 300-second timeout.
The broader platform advertises endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and data generation — all at the same $0.02/request price point. However, documentation beyond the landing page 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 usage examples available from the crawled material.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time crypto quotes, gas estimates, and exchange rates on a per-call basis
- —Running geocoding, validation, or data conversion tasks with micropayments
- —Integrating pay-per-use analytics and data export into agent workflows
Fit
Best for
- —Agents needing keyless, pay-per-call access to diverse utility APIs
- —Developers who want to avoid subscription commitments for low-volume API usage
- —x402-compatible clients on the Base network looking for cheap micropayment endpoints
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited tiers
- —Users without USDC on Base network or x402-compatible payment infrastructure
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/199 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page, and no examples. The actual functionality behind 'Premium API Access' at /api/v1/charges/199 is unclear — it could be a generic charge endpoint or a specific service. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — all /docs, /pricing, /api, /README pages return only 'Connect wallet' with no content
- —The specific purpose of /api/v1/charges/199 ('Premium API Access') is not documented; it is unclear what data or service it returns
- —No request body schema or response schema is provided anywhere in the crawled material
- —The platform lists many endpoints on its landing page but none have documented input/output contracts
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/charges/199 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/199
- —The platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com