DEX Swap Quotes API
Best swap quotes across DEXes (Uniswap, SushiSwap, Aerodrome). Base & Ethereum. x402.
Install
Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).
claude mcp add --transport sse dex-swap-quotes-api 'https://dex-quotes.api.klymax402.com/mcp'{
"mcpServers": {
"dex-swap-quotes-api": {
"type": "sse",
"url": "https://dex-quotes.api.klymax402.com/mcp"
}
}
}Documentation
From the project's README on GitHub, refreshed weekly. Links open on GitHub.
Contents
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 bodyAny 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 | $0.012 | Get the best swap quote across multiple DEXes |
dex_get_swap_quote | POST | /api/quote | $0.012 | Get the best swap quote across multiple DEXes (POST variant) |
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).
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. POST variant of dex_get_swap_quote -- same params passed as JSON body instead of query string.
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"
- "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
Frequently asked questions
What is DEX Swap Quotes API?
Best swap quotes across DEXes (Uniswap, SushiSwap, Aerodrome). Base & Ethereum. x402.
How do I install DEX Swap Quotes API?
It runs as a remote server. In Claude Code: claude mcp add --transport sse dex-swap-quotes-api 'https://dex-quotes.api.klymax402.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.
Does DEX Swap Quotes API need an API key?
Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.
Is DEX Swap Quotes API open source?
Yes. Its code is on GitHub under the MIT license.
Who maintains DEX Swap Quotes API?
It is published by Br0ski777. AI.tn lists it but does not maintain or endorse it.
From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.