Pay-per-call API suite on Base (USDC) covering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad collection of endpoints spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities. 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 required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The specific endpoint at `/api/v1/data` is listed as "Premium API Access" and accepts POST requests. The x402 challenge confirms it is live, requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The broader platform advertises sibling endpoints for metrics, reports, data export, insights, sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation — all at the same $0.02 price point.
Documentation is extremely thin: the /docs, /pricing, /api, 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 crawl. The actual behavior and response format of each endpoint is unknown beyond what the x402 challenge's outputSchema hints at (HTTP POST, discoverable, application/json).
Capabilities
Use cases
- —Fetching real-time financial data or crypto quotes without API key management
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) on a per-call payment basis
- —Geocoding or data conversion via utility endpoints with no subscription commitment
- —Agents autonomously purchasing API calls using x402 USDC payments on Base
Fit
Best for
- —AI agents that need frictionless, keyless API access via x402
- —Developers who want pay-as-you-go pricing with no signup or rate limits
- —Web3-native applications that can settle micropayments in USDC on Base
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription discounts
- —Anyone unable to transact in USDC on the Base network
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/data \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02/request in USDC on Base), but there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The actual functionality behind each endpoint is unverifiable from available material.
Warnings
- —No OpenAPI specification or schema documentation available
- —All documentation pages (/docs, /pricing, /api, /README) render only 'Connect wallet' with no content
- —Request and response formats for all endpoints are undocumented and unknown
- —The breadth of advertised capabilities (AI, finance, geo, etc.) cannot be verified from crawl data alone
Citations
- —The endpoint returns a 402 challenge requesting up to 20000 base units of USDC (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Basehttps://lowpaymentfee.com/api/v1/data
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The platform advertises endpoints across Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) show only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs