Dex Quotes X402
DEX Swap Quotes API
Best swap quotes across Uniswap, SushiSwap, Aerodrome -- price impact, route, slippage. Pre-trade essential. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.
Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.
Quickstart -- MCP
Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):
{
"mcpServers": {
"dex-quotes": {
"url": "https://dex-quotes.api.klymax402.com/mcp"
}
}
}
Quickstart -- HTTP (x402)
curl "https://dex-quotes.api.klymax402.com/api/quote?tokenIn=...&tokenOut=...&amount=..."
# -> 402 Payment Required, with an x402 payment challenge in the response body
Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.
Tools
| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
dex_get_swap_quote | GET | /api/quote | $0.005 | Get the best swap quote across multiple DEXes |
dex_get_swap_quote
Use this when you need a swap quote before trading tokens on-chain. Returns the best price across multiple DEXes in JSON.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
tokenIn | string | yes | Contract address of input token (e.g. 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 for USDC on Base) |
tokenOut | string | yes | Contract address of output token (e.g. 0x4200000000000000000000000000000000000006 for WETH on Base) |
amount | string | yes | Amount of input token in raw units (wei/smallest unit, e.g. 1000000 for 1 USDC) |
chain | string | no | Blockchain network: base or ethereum (default: base) |
Returns
bestDex-- which DEX offers the best rate (Uniswap, SushiSwap, Aerodrome)amountOut-- expected output token amountpriceImpact-- percentage price impact of the trademinimumReceived-- minimum output after slippage toleranceroute-- swap path (e.g. USDC -> WETH -> TOKEN)gasEstimateUsd-- estimated gas cost in USD
Example response:
{"bestDex":"Uniswap V3","amountOut":"0.3215","priceImpact":"0.12%","minimumReceived":"0.3183","route":["USDC","WETH"],"gasEstimateUsd":0.04}
When to use: executing any token swap to find the best rate and estimate slippage. Essential for trade sizing and DEX comparison.
Not for: gas estimation only (use gas_get_current_price), yield opportunities (use defi_find_best_yields), wallet balance (use wallet_get_portfolio).
Example agent prompts
- "A swap quote before trading tokens on-chain"
Payment
- Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
- Network: Base L2 (
eip155:8453) - Asset: USDC
- Facilitator: Coinbase CDP (primary), PayAI (fallback)
- Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)
Part of klymax402
100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.
- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats
License
MIT
Server Config
{
"mcpServers": {
"dex-quotes": {
"url": "https://dex-quotes-x402-production.up.railway.app/mcp",
"transport": "sse"
}
}
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