Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of pay-per-request endpoints across data analytics, AI/ML inference, finance/Web3, and infrastructure utilities. All endpoints are priced at $0.02 per request, settled in USDC on the Base network. The x402 protocol means no API keys, no accounts, and no rate limits — callers simply attach a payment header to each request.
The specific endpoint at `/api/v1/payments/371` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) on Base. The payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the "exact" scheme with a 300-second timeout. The endpoint accepts POST requests and returns `application/json`.
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. However, documentation beyond the landing page is extremely thin: the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. Without OpenAPI schemas, request/response examples, or detailed documentation, it is unclear what inputs each endpoint expects or what shape the responses take.
Capabilities
Use cases
- —Accessing premium API functionality with per-call USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Programmatic access to data, AI, finance, or utility endpoints without subscription commitments
Fit
Best for
- —Developers or agents who want zero-signup, pay-per-use API access
- —x402-compatible clients on the Base network
- —Low-volume or sporadic API consumers who don't want subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited plans
- —Anyone without a Base-network USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/payments/371 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-header>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, there is no OpenAPI schema, no request/response examples, and all documentation pages beyond the landing page are empty ('Connect wallet' only). The purpose of this specific '/payments/371' endpoint is unclear beyond the generic 'Premium API Access' label.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown.
- —All doc/pricing/API/README pages render only 'Connect wallet' with no usable content.
- —The specific function of /api/v1/payments/371 ('Premium API Access') is not described anywhere; it may be a generic or placeholder endpoint.
- —Cannot verify what data or service this endpoint actually returns.
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 (0.02 USD) on Base with 300-second timeouthttps://lowpaymentfee.com/api/v1/payments/371
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/payments/371