Pay-per-request API platform on Base network via x402 — $0.02/call 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 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, rate limits, or subscriptions are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/carts/16` 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 equals $0.02 per call, consistent with the site's uniform pricing. The endpoint accepts POST requests and returns application/json responses.
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 price point. Documentation pages (docs, pricing, README) appear to require wallet connection and contain no substantive content in the crawl. No OpenAPI schema, request/response examples, or detailed documentation were found, so the actual behavior and data returned by this specific cart endpoint remain unclear.
Capabilities
Use cases
- —Accessing premium API data with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Programmatic purchasing or cart retrieval via x402 payment protocol
Fit
Best for
- —Developers wanting zero-commitment, pay-per-call API access
- —AI agents that can settle x402 payments autonomously on Base
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may add up compared to bulk plans
- —Users without access to USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/16 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing. However, there is no OpenAPI schema, no request/response examples, and documentation pages are empty (wallet-gated). The purpose of the specific '/api/v1/carts/16' endpoint is unclear beyond the generic 'Premium API Access' label. Effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available for this endpoint
- —Documentation, pricing, and README pages are wallet-gated and contain no crawlable content
- —The specific purpose and expected input/output of /api/v1/carts/16 is undocumented
- —The platform lists many endpoints but none have detailed docs visible without wallet connection
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —Payment settled in USDC on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/carts/16
- —Platform offers endpoints across data analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com