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 variety of endpoints across data & analytics, AI & machine learning, finance & Web3, and infrastructure categories. All endpoints are pay-per-call at $0.02 per request, settled in USDC on the Base network. No API keys, rate limits, or subscriptions are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/249` is listed as "Premium API Access" and advertises a max amount of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and returns application/json. The x402 challenge was successfully captured, confirming the endpoint is live.
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. However, documentation pages (docs, pricing, README) returned only a "Connect wallet" prompt with no substantive content, so the actual behavior and response schemas of these endpoints remain undocumented and unverified.
Capabilities
Use cases
- —Agents needing on-demand API access without API key provisioning
- —Micropayment-gated data retrieval for analytics or finance workflows
- —AI inference calls (sentiment, summarization, classification) paid per request
- —Utility operations like geocoding or data conversion with instant crypto settlement
Fit
Best for
- —AI agents that can settle x402 payments in USDC on Base
- —Developers wanting zero-signup, pay-as-you-go API access
- —Low-volume or bursty workloads where per-call pricing is economical
Not for
- —High-volume production workloads needing guaranteed SLAs and documented schemas
- —Users without USDC on Base network or x402-compatible payment infrastructure
- —Applications requiring detailed API documentation and response schema guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/transactions/249 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base). However, there is no OpenAPI schema, no documentation of request/response formats, and the docs/pricing/README pages are all empty stubs. The specific purpose of the /transactions/249 endpoint beyond 'Premium API Access' is unknown.
Warnings
- —Documentation pages (/docs, /pricing, /README) return no useful content — only a 'Connect wallet' prompt.
- —No OpenAPI or schema definition is available for any endpoint.
- —The specific functionality of /api/v1/transactions/249 ('Premium API Access') is undocumented — it is unclear what data or service it provides.
- —Response format and required request body fields are unknown.
- —The platform lists many endpoint categories (AI, finance, analytics, etc.) but none have verifiable documentation.
Citations
- —Endpoint returns 402 with x402 challenge advertising 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/transactions/249
- —Platform lists endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure at $0.02/requesthttps://lowpaymentfee.com
- —USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/transactions/249
- —No API keys, no rate limits, instant access advertisedhttps://lowpaymentfee.com