Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a broad catalog of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, payable in USDC on the Base network with no API keys, no rate limits, and no minimum commitments.
The specific endpoint `/api/v1/charges/239` is listed as "Premium API Access" and returns a standard x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is made via the x402 exact scheme, settling to the specified payTo address. The endpoint accepts HTTP POST requests and returns application/json responses.
Documentation is extremely sparse — the /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no examples of what this particular endpoint actually returns. The site's landing page confirms the pricing model and lists the available API categories, but does not describe the specific functionality behind `/api/v1/charges/239`. Without documentation, it is unclear what data or service this particular charge endpoint provides versus the other named endpoints on the platform.
Capabilities
Use cases
- —Accessing pay-per-request API services without API key registration
- —Making micropayments for API calls using USDC on Base
- —Agent-driven programmatic access to premium endpoints via x402 protocol
Fit
Best for
- —Developers wanting keyless, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or schemas before purchasing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/239 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no OpenAPI spec, no documentation beyond a landing page listing, no request/response schema, and no examples. The specific functionality of /api/v1/charges/239 ('Premium API Access') is undefined — it's unclear what it actually does. This is effectively a stub listing.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet' with no content
- —No OpenAPI or schema describing request parameters or response format
- —The specific purpose of /api/v1/charges/239 is not documented; 'Premium API Access' is a generic label
- —Cannot verify what data or service is returned after payment
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/239
- —Site lists APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com