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/payments/170` is labeled "Premium API Access" and returns a valid x402 challenge with a maxAmountRequired of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals). Payment is made via the x402 exact scheme to the specified wallet address. The endpoint accepts POST requests and returns application/json responses. No API keys are required; access is granted per-payment with no rate limits advertised.
Documentation is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what this particular endpoint actually returns. The site's landing page lists many endpoints but does not clarify what `/api/v1/payments/170` specifically does versus the other listed routes. Prospective users 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 workflows that need keyless, pay-as-you-go API access on Base
- —Testing x402 payment protocol integrations against a live endpoint
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents needing keyless pay-per-request API access
- —Users who want to avoid subscriptions and pay only per call
Not for
- —Users who need detailed API documentation or guaranteed SLAs
- —High-volume use cases where per-call pricing may be inefficient
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/170 \
-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 schema, no request/response examples, and no documentation explaining what this endpoint actually does or returns. The docs pages are empty beyond a wallet-connect prompt. The listing is effectively a stub with confirmed liveness.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or schema describing request parameters or response format
- —The specific functionality of /api/v1/payments/170 ('Premium API Access') is not explained anywhere
- —No examples of request bodies or response payloads available
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/payments/170
- —Site lists APIs across data & analytics, AI/ML, finance & Web3, and infrastructure categorieshttps://lowpaymentfee.com