Pay-per-call API platform on Base (USDC) via x402 — $0.02/request, no API keys required.
What it does
lowpaymentfee.com is a pay-per-request API platform that uses the x402 protocol to accept USDC payments on the Base network. The specific endpoint `/api/v1/payments/320` is listed as "Premium API Access" and costs $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, accounts, or rate limits are advertised — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises multiple API categories including Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are listed at the same $0.02/request price point and settle via USDC on Base.
Documentation is extremely sparse — the docs, pricing, and API 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 the `/api/v1/payments/320` endpoint actually returns. The endpoint is live (returns a valid 402 challenge), but without documentation it is unclear what data or functionality it provides beyond the generic "Premium API Access" label.
Capabilities
Use cases
- —Agent-driven API consumption with automatic per-call USDC micropayments
- —Accessing premium data or services without account registration or API key management
- —Programmatic pay-as-you-go access to analytics, AI, finance, or utility endpoints
Fit
Best for
- —Developers or agents wanting zero-signup, pay-per-use API access
- —x402-compatible clients on the Base network
- —Low-volume or sporadic API consumers who prefer no subscriptions
Not for
- —Users needing detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who need bulk pricing or rate-limit guarantees
- —Anyone without a Base-network USDC wallet or x402-compatible client
Quick start
# The endpoint expects an x402 X-PAYMENT header with a valid payment proof.
# Without a payment SDK this is illustrative only.
curl -X POST https://lowpaymentfee.com/api/v1/payments/320 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC on Base at $0.02/request. However, there is no OpenAPI schema, no request/response examples, and no documentation beyond a wallet-connect prompt. The purpose of this specific endpoint (/api/v1/payments/320) is entirely unclear — 'Premium API Access' is a generic label with no specification of inputs or outputs.
Warnings
- —No documentation available — docs, pricing, and API pages all show only 'Connect wallet' with no content
- —No OpenAPI or JSON schema describing request parameters or response format
- —The specific function of /api/v1/payments/320 ('Premium API Access') is undocumented and unclear
- —Cannot verify what data or service is actually returned after payment
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 USDC base units on Base networkhttps://lowpaymentfee.com/api/v1/payments/320
- —All endpoints are listed at $0.02/request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/320