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 catalog of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are pay-per-request at $0.02 each, settled in USDC on the Base network. No API keys, accounts, or rate limits are required — callers simply attach an x402 payment header to each request.
The specific endpoint at `/api/v1/transactions/283` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals) on Base. The payment scheme is "exact" with a 300-second timeout. The broader platform advertises additional endpoints for sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, gas estimates, geocoding, validation, conversion, and data export — all at the same $0.02 price point.
Documentation is extremely sparse. 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 example payloads available. The actual functionality behind each endpoint is unclear beyond the short labels on the landing page. The endpoint is live and responds with a valid x402 challenge, but without documentation it is difficult to know what data or results any given endpoint returns.
Capabilities
Use cases
- —Accessing analytics metrics or reports on a per-request basis without subscription
- —Running AI inference tasks (sentiment, summarization, classification, embeddings) with per-call payment
- —Fetching crypto token quotes, gas estimates, or exchange rates via micropayment
- —Geocoding or data validation without needing an API key or account
Fit
Best for
- —Developers who want zero-signup, pay-as-you-go API access
- —AI agents that can settle x402 payments in USDC on Base
- —Projects needing occasional API calls without committing to a subscription
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume consumers who would benefit from bulk pricing or rate-limited plans
- —Anyone without a Base-compatible USDC wallet
Quick start
# The endpoint returns HTTP 402 with an x402 challenge.
# Use an x402-compatible client to auto-settle the $0.02 USDC payment.
curl -X POST https://lowpaymentfee.com/api/v1/transactions/283 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, confirming it works at the protocol level. However, documentation is essentially nonexistent — every doc/pricing/readme page shows only 'Connect wallet'. There is no OpenAPI spec, no request/response schemas, and no examples. The actual functionality behind 'Premium API Access' at /api/v1/transactions/283 is unknown.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages are all blank beyond a wallet-connect prompt
- —No OpenAPI or schema definitions found; request and response formats are completely undocumented
- —The specific purpose of /api/v1/transactions/283 ('Premium API Access') is unclear — it does not match any of the named endpoints on the landing page
- —Cannot verify what data or service any endpoint actually returns without paying
Citations
- —All endpoints priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —x402 challenge returns maxAmountRequired of 20000 base units of USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base, equaling $0.02https://lowpaymentfee.com/api/v1/transactions/283
- —Platform offers endpoints for analytics, AI/ML, finance/Web3, and infrastructure utilitieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /pricing, /api, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs