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 collection of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request using USDC on the Base network, with no API keys, no rate limits, and no subscriptions required. The specific endpoint at `/api/v1/transactions/291` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 per call (USDC uses 6 decimals).
The platform advertises 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 listed endpoints share the same $0.02 price point. Payment is handled via the x402 protocol's exact scheme, settling on-chain on Base.
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 spec, no request/response schema documentation, and no usage examples available from the crawled material. The actual functionality behind the `/api/v1/transactions/291` endpoint is unclear beyond its "Premium API Access" label.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data and crypto gas estimates on a per-call basis
- —Running geocoding or data validation utilities with instant crypto-settled payments
- —Exporting analytics data or generating reports via pay-as-you-go endpoints
Fit
Best for
- —Developers wanting zero-friction API access without subscriptions or API keys
- —Agents and bots that can settle x402 payments autonomously on Base
- —Low-volume or bursty workloads where per-request pricing is cost-effective
Not for
- —High-volume production workloads needing SLAs, rate guarantees, or dedicated support
- —Users who need detailed API documentation, request/response schemas, or sandbox environments
Quick start
# The endpoint requires an x402 payment header (USDC on Base).
# 1. POST to the endpoint without payment to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/transactions/291
# 2. Parse the 402 JSON, construct an x402 payment proof for 0.02 USDC,
# then re-send with the X-PAYMENT header.Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming pricing and payment details. However, documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI spec, no request/response schema, no examples, and the actual functionality of the /api/v1/transactions/291 endpoint is opaque beyond its generic 'Premium API Access' label.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all render only 'Connect wallet' with no content.
- —No OpenAPI or schema definition found for any endpoint.
- —The specific purpose of /api/v1/transactions/291 ('Premium API Access') is unclear; it does not match any of the named endpoint categories on the homepage.
- —Cannot verify actual functionality or response format without paying and calling the endpoint.
Citations
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base network.https://lowpaymentfee.com
- —The 402 challenge for /api/v1/transactions/291 requests maxAmountRequired of 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base.https://lowpaymentfee.com/api/v1/transactions/291
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure.https://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) show only 'Connect wallet' with no further content.https://lowpaymentfee.com/docs