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, and infrastructure utilities. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/carts/48` 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 advertised pricing. The payment scheme is "exact" with a 300-second timeout, and the endpoint accepts POST requests.
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. However, the specific functionality behind the `/api/v1/carts/48` path is not documented beyond the generic "Premium API Access" label. Documentation pages (docs, pricing, README) all returned minimal content (just a "Connect wallet" prompt), so detailed request/response schemas are unavailable.
Capabilities
Use cases
- —Accessing premium API endpoints without needing API keys or subscriptions
- —Making low-cost per-request API calls settled on-chain via USDC on Base
- —Integrating pay-as-you-go API access into autonomous agent workflows
Fit
Best for
- —Developers wanting frictionless pay-per-use API access without accounts
- —AI agents that need to purchase API calls programmatically via x402
- —Projects requiring low-cost on-chain micropayments for API consumption
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscriptions
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/carts/48 \
-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, the specific functionality of /api/v1/carts/48 is undocumented, no request/response schemas are available, and all documentation pages returned only 'Connect wallet' with no useful content. The listing is effectively a stub with confirmed liveness and pricing.
Warnings
- —The specific functionality of /api/v1/carts/48 ('Premium API Access') is not documented — it is unclear what this endpoint actually does or returns.
- —All documentation pages (/docs, /pricing, /README, /api) returned only 'Connect wallet' with no substantive content.
- —No OpenAPI spec, request schema, or response schema is available for this endpoint.
- —The broader platform lists many endpoints (AI, finance, analytics, etc.) but none have documented schemas or example payloads.
Citations
- —All endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The x402 challenge for /api/v1/carts/48 requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/carts/48
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com