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 set 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 at a flat rate of $0.02 per call, with no API keys, no rate limits, and no commitments required.
The specific endpoint at `/api/v1/transactions/293` 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. Payment is made via the x402 exact scheme with a 300-second timeout. The platform advertises additional 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 (geocoding, validation, conversion, generation).
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 endpoint is confirmed live (402 challenge captured), but without documentation it is unclear what input this specific `/transactions/293` endpoint expects or what it returns.
Capabilities
Use cases
- —Accessing AI inference endpoints (sentiment, summarization, classification, embeddings) without API key management
- —Fetching real-time financial data like token quotes, gas estimates, and exchange rates on a per-call basis
- —Running utility operations like geocoding, validation, and data conversion with micropayments
Fit
Best for
- —Agents or developers wanting zero-setup, pay-as-you-go API access
- —x402-compatible clients that can settle USDC payments on Base
- —Low-volume or bursty workloads where subscription pricing is wasteful
Not for
- —High-volume production workloads needing SLAs or guaranteed uptime documentation
- —Users who need detailed API documentation, request/response schemas, or integration guides before committing
Quick start
# The endpoint expects an x402 payment header (USDC on Base, $0.02 per call)
curl -X POST https://lowpaymentfee.com/api/v1/transactions/293 \
-H 'Content-Type: application/json' \
-H 'X-PAYMENT: <x402-payment-token>'Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a landing page listing, and no examples. The specific purpose of /api/v1/transactions/293 is undocumented. This is effectively a stub listing.
Warnings
- —No OpenAPI or schema documentation available — all /docs, /api, /pricing, /README pages return only 'Connect wallet' with no content
- —The specific purpose and expected input/output of /api/v1/transactions/293 ('Premium API Access') is undocumented
- —No request or response examples could be found in crawled material
- —Platform reliability, uptime, and data freshness are unknown
Citations
- —Flat pricing of $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —402 challenge requests maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/transactions/293
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com