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, settled in USDC on the Base network.
The specific endpoint `/api/v1/charges/288` is labeled "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02. Payment is made via the x402 exact scheme — no API keys, no rate limits, and no upfront commitments are required. The endpoint accepts POST requests and returns application/json.
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 lists many API paths but does not describe their input parameters or output formats. Without documentation, it is unclear what payload to send or what response to expect from `/api/v1/charges/288` specifically.
Capabilities
Use cases
- —Accessing pay-per-request API services without API key registration
- —Making micropayments for API calls using USDC on Base
- —Agent-driven API consumption with x402 payment protocol
Fit
Best for
- —Developers wanting zero-signup API access with crypto micropayments
- —AI agents that can settle x402 payments autonomously
- —Users who prefer pay-as-you-go pricing without subscriptions
Not for
- —Users needing detailed API documentation or schemas before integrating
- —High-volume consumers who need bulk pricing or rate guarantees
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/288 \
-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, confirming it works. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, and no description of what this specific endpoint does beyond the generic label 'Premium API Access'. The listing is effectively a stub.
Warnings
- —No documentation available — /docs, /pricing, /api, and /README all render only 'Connect wallet'
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose of /api/v1/charges/288 ('Premium API Access') is unclear — it does not correspond to any named endpoint on the landing page
- —Cannot determine expected request body or response format
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/288
- —Site lists APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com