Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
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/transactions/15` is labeled "Premium API Access" and requires a payment of up to 20,000 base units of USDC (i.e., $0.02) per call. The platform advertises no API keys, no rate limits, and instant access — you simply attach an x402 payment header to each request.
The broader platform offers endpoints across four categories: 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.
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 the `/api/v1/transactions/15` 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 its generic "Premium API Access" label.
Capabilities
Use cases
- —Accessing data analytics and reports on a per-request payment basis without subscriptions
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with per-call USDC payments
- —Fetching crypto price feeds, exchange rates, and gas estimates via micropayments
- —Geocoding and data conversion utilities paid per use
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —Agents and bots that can attach x402 payment headers automatically
- —Users who prefer crypto-native (USDC on Base) billing over traditional API keys
Not for
- —Users needing detailed API documentation or OpenAPI specs before integration
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Developers unfamiliar with x402 protocol or crypto wallet-based payments
Quick start
# The endpoint requires an x402 payment header with USDC on Base.
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/15
# 2. Parse the 402 response, construct the X-PAYMENT header
# with a signed USDC payment of $0.02 (20000 base units),
# then resend with the header attached.Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it accepts USDC payments on Base. However, documentation is effectively nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and no explanation of what 'Premium API Access' at /api/v1/transactions/15 actually returns. The listing is essentially a stub.
Warnings
- —No documentation available — all doc/pricing/API/README pages render only 'Connect wallet'
- —No OpenAPI or JSON schema describing request parameters or response format
- —The specific purpose of /api/v1/transactions/15 ('Premium API Access') is undocumented and unclear
- —Cannot verify what data or functionality any of the advertised endpoints actually provide
Citations
- —The endpoint returns a 402 challenge requesting up to 20,000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base networkhttps://lowpaymentfee.com/api/v1/transactions/15
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Docs, API, pricing, and README pages all show only 'Connect wallet' with no further contenthttps://lowpaymentfee.com/docs