Pay-per-call API platform on Base network via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad catalog of endpoints spanning 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, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/154` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02, since USDC uses 6 decimals) on Base. The payment scheme is "exact" with a 300-second timeout. The endpoint accepts POST requests and returns application/json.
The broader platform advertises categories including: metrics and reports APIs, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation. However, documentation is extremely thin — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further technical detail. There are no OpenAPI specs, request/response schemas, or usage examples available from the crawled content, so the actual behavior and output of each endpoint (including this one) cannot be verified beyond the x402 challenge metadata.
Capabilities
Use cases
- —Accessing pay-per-call API endpoints without needing an API key or subscription
- —Making one-off data or AI inference requests settled instantly in USDC on Base
- —Integrating agent-driven workflows that pay for each API call via x402 protocol
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously on Base
- —Projects needing low-cost ($0.02) per-request API calls without rate limits
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
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/154 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is virtually no documentation: no OpenAPI spec, no request/response schemas, no examples, and all doc pages render only 'Connect wallet'. The actual functionality behind 'Premium API Access' at /api/v1/transactions/154 is unknown. Pricing is clear ($0.02) but everything else must be inferred or is missing.
Warnings
- —No OpenAPI spec or request/response schema available for this endpoint
- —All documentation pages (docs, API, pricing, README) render only 'Connect wallet' with no usable content
- —The specific purpose of /api/v1/transactions/154 ('Premium API Access') is not described anywhere — it is unclear what data or service it provides
- —Cannot verify actual endpoint behavior or output format beyond the x402 challenge metadata
Citations
- —All endpoints priced at $0.02 per request, no API keys, no rate limits, Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, which equals $0.02https://lowpaymentfee.com/api/v1/transactions/154
- —Platform offers endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com