Pay-per-call market quote API for crypto tokens, settled in USDC on Base via x402.
What it does
The `/api/v1/market/quote/COIN` endpoint on lowpaymentfee.com provides market quote data for cryptocurrency tokens. It is part of a broader platform offering data & analytics, AI/ML inference, finance/Web3, and infrastructure utility APIs—all priced at $0.02 per request with no API keys, no rate limits, and no commitments.
This specific endpoint accepts POST requests and returns JSON. Payment is handled via the x402 protocol: callers attach an `X-PAYMENT` header containing a payment proof settled in USDC on the Base network. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02. The payment is sent to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` with a timeout of 300 seconds.
Documentation beyond the landing page is extremely sparse—the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional technical detail. There is no OpenAPI schema, no request/response examples, and no description of what parameters the POST body should contain or what fields the quote response includes. The `COIN` path segment presumably accepts a token symbol or identifier, but this is not documented.
Capabilities
Use cases
- —Fetching real-time market quotes for cryptocurrency tokens in automated trading bots
- —Retrieving token price data for portfolio dashboards without managing API keys
- —Agent-driven price lookups where per-call micropayments replace subscription billing
Fit
Best for
- —Agents or bots that need on-demand crypto quotes without subscription overhead
- —Developers wanting keyless, pay-per-use market data on Base network
- —Low-volume or bursty workloads where flat $0.02/call pricing is economical
Not for
- —High-frequency trading requiring sub-second latency guarantees (no SLA documented)
- —Users who need detailed historical OHLCV candle data (not evidenced by this endpoint)
- —Non-crypto callers who cannot settle USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/market/quote/COIN \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>" \
-d '{"symbol": "ETH"}'Example
Request
{
"symbol": "ETH"
}Endpoint
Quality
The endpoint is live (402 challenge captured) and pricing is clear ($0.02/call in USDC on Base). However, there is no OpenAPI schema, no documented request/response format, no examples, and all documentation pages return only a wallet-connect prompt. The actual behavior of the endpoint is almost entirely unknown.
Warnings
- —No documentation available—docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —Request body schema is unknown; the example request is inferred/guessed from the path pattern.
- —Response schema is completely unknown; no example response can be provided.
- —The path segment 'COIN' is ambiguous—unclear whether it is a literal path or a placeholder for a token symbol.
Citations
- —Endpoint returns 402 with x402 challenge requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/market/quote/COIN
- —maxAmountRequired is 20000 base units of USDC (USD Coin, 6 decimals) = $0.02https://lowpaymentfee.com/api/v1/market/quote/COIN
- —Platform advertises $0.02/request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Payment address is 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with 300s timeouthttps://lowpaymentfee.com/api/v1/market/quote/COIN