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/71` is labeled "Premium API Access" in the x402 challenge and accepts POST requests. The challenge advertises 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 with no API keys or rate limits required — callers simply attach an X-PAYMENT header to each request.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed description of what the `/api/v1/charges/71` endpoint actually returns. The site's landing page lists many endpoints but does not clarify what this particular charge ID maps to. Prospective callers should be aware that the actual functionality behind this endpoint is undocumented.
Capabilities
Use cases
- —Programmatic access to premium API services with per-call USDC micropayments
- —Agent-driven API consumption without pre-registration or API keys
- —Integrating pay-as-you-go endpoints into automated workflows on Base
Fit
Best for
- —Developers wanting zero-signup, pay-per-request API access
- —AI agents that can settle x402 payments in USDC on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users needing detailed API documentation or guaranteed SLAs
- —Anyone without a Base-compatible USDC wallet
- —High-volume consumers who need bulk pricing or rate guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/71 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts payments. However, there is no OpenAPI schema, no request/response examples, and no documentation beyond a landing page listing. The specific functionality of /api/v1/charges/71 is entirely unclear — it could map to any of the listed services or something else. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —The specific functionality of /api/v1/charges/71 ('Premium API Access') is not described anywhere
- —No OpenAPI schema or request/response examples provided
- —No information on uptime, SLAs, or rate limits beyond marketing claims of 'no rate limits'
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge shows maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/charges/71
- —Site offers APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com