Pay-per-call API platform on Base network 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 endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. Every endpoint costs $0.02 per request, paid in USDC on the Base network via the x402 protocol. There are no API keys, no rate limits, and no signup — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/190` is listed as "Premium API Access" but its exact functionality is not documented beyond that label. The x402 challenge confirms it is live, accepts POST requests, and requires up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.
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 pages (docs, pricing, README) returned only a "Connect wallet" prompt with no further technical detail, so the actual request/response schemas for this and other endpoints remain unknown.
Capabilities
Use cases
- —Accessing premium API functionality with per-call USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Prototyping integrations without signup or subscription commitments
Fit
Best for
- —Developers who want zero-signup, pay-as-you-go API access
- —AI agents with x402-compatible wallets on Base
- —Low-volume or bursty workloads where subscriptions are wasteful
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume production workloads where $0.02/request adds up significantly
- —Teams that require traditional API key authentication and usage dashboards
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/190 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and the specific purpose of the /transactions/190 endpoint is entirely undocumented. The docs, pricing, and README pages all returned only 'Connect wallet' with no useful content.
Warnings
- —The exact functionality of /api/v1/transactions/190 ('Premium API Access') is undocumented — purpose is unknown.
- —All documentation pages (docs, pricing, README) returned only a 'Connect wallet' prompt with no technical content.
- —No OpenAPI spec, request schema, or response schema is available for any endpoint.
- —The broader platform lists many endpoints but none have documented input/output contracts.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/transactions/190
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/transactions/190
- —All endpoints cost $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com