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First Dollar On-Chain Quote API
x402
First Dollar On-Chain Quote API is a paid API for AI agents from firstdollar-api.onrender.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).
Fetches a live token swap quote on Base chain given an input token, output token, and amount
Price / call$0.02
Success—
StatusUnknown
How this service works
Live Base chain reads sold per call over x402 (exact, USDC on Base, $0.02/call).
Output
Returns a live quote from Base chain for the requested token swap, including the expected output amount for the given input token and amount, reflecting real-time on-chain liquidity and pricing.
Example use cases
Pre-trade swap rate check
“Before I execute a trade, can you pull the live Base chain quote for swapping 500 USDC into WETH so I know how much ETH I'd get?”
Arbitrage price monitoring
“Check the current on-chain quote for swapping 1 WETH to USDC on Base — I want to see if the rate is favorable compared to what I saw an hour ago.”
Token price lookup for portfolio valuation
“I need to know how much USDC I'd get for 0.5 WETH right now on Base chain — just give me the live quote.”
Technical details
Endpoint
GEThttps://firstdollar-api.onrender.com/quote?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a real-time, on-chain swap quote specifically on the Base chain and are comfortable paying $0.02 USDC per call via x402 micropayment. Prefer it over off-chain price feeds when accuracy to actual on-chain liquidity matters, or when building agents that need to verify executable swap rates rather than indicative market prices.
Side effects
- Unsupported token symbol or invalid 0x address returns an error
- Token pair with insufficient liquidity may return no quote or a degraded result
- Missing required query parameters (tokenIn, tokenOut, amountIn) results in a validation error
- Payment failure over x402 (insufficient USDC balance or authorization) blocks the response
- Network or RPC issues on Base chain may cause temporary unavailability
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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