OnlySwaps MCP Server

Multi-chain DEX meta-aggregator for AI agents. Queries 15+ DEX aggregators, returns the best price.

MCP (Model Context Protocol) server that enables AI agents to execute token swaps. We query 0x, 1inch, Paraswap, DODO, Uniswap, Li.Fi, and 10+ more sources, returning only the best available quotes.

Why OnlySwaps?

• Meta-Aggregator: Queries 15+ DEX aggregators (0x, 1inch, Paraswap, Li.Fi, etc.) and returns the best available price
• 13 Chains: Ethereum, Base, Arbitrum, Optimism, Polygon, BSC, Avalanche, Solana, and more
• One Integration: Single API call to access all DEX liquidity across all chains
• AI-Native: Built for MCP - works with Claude Desktop, Cursor, and any MCP client

Tools

| Tool | Description | |------|-------------| | get_quote | Get swap quotes from multiple DEX aggregators | | build_swap_tx | Build unsigned swap transaction (ready for client-side signing) | | execute_swap | Execute swap end-to-end with embedded wallet (Privy) | | get_portfolio | Get user token holdings across chains | | get_tx_status | Check transaction status | | estimate_gas | Estimate gas for a transaction | | search_token | Search tokens by name or symbol |

Quick Start

Using npx

npx @onlyswaps/mcp-server

Claude Desktop Configuration

Add to ~/.claude/claude_desktop_config.json:

{
  "mcpServers": {
    "onlyswaps": {
      "command": "npx",
      "args": ["-y", "@onlyswaps/mcp-server", "stdio"],
      "env": {
        "ONLYSWAPS_API_URL": "https://api.onlyswaps.fyi"
      }
    }
  }
}

Hosted Server (SSE)

Connect to our hosted MCP server:

https://mcp.onlyswaps.fyi/mcp

Supported Chains

| Chain | ID | Native Token | |-------|-----|--------------| | Ethereum | 1 | ETH | | Optimism | 10 | ETH | | BSC | 56 | BNB | | Gnosis | 100 | xDAI | | Polygon | 137 | MATIC | | Fantom | 250 | FTM | | zkSync Era | 324 | ETH | | Base | 8453 | ETH | | Arbitrum | 42161 | ETH | | Avalanche | 43114 | AVAX | | Linea | 59144 | ETH | | Scroll | 534352 | ETH | | Solana | solana | SOL |

Tool Examples

get_quote

Get the best swap quote across all aggregators.

{
  "fromToken": "ETH",
  "toToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "amount": "1000000000000000000",
  "chainId": "base"
}

Returns:

{
  "bestQuote": {
    "provider": "1inch",
    "buyAmount": "3245000000",
    "sellAmount": "1000000000000000000",
    "estimatedGas": "150000",
    "priceImpact": "0.05"
  },
  "allQuotes": [...],
  "meta": { "chain": "Base", "chainId": 8453, "sourcesQueried": 5 }
}

build_swap_tx

Build an unsigned transaction ready for client-side signing.

{
  "fromToken": "ETH",
  "toToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "amount": "1000000000000000000",
  "chainId": "base",
  "userAddress": "0xYourWalletAddress",
  "slippage": 1
}

Returns transaction data (to, data, value, gas, chainId) ready to sign.

execute_swap

Execute a swap end-to-end using an embedded Privy wallet. Requires Privy configuration.

{
  "fromToken": "ETH",
  "toToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "amount": "1000000000000000000",
  "chainId": "base",
  "userId": "privy-user-id"
}

get_portfolio

Get user token holdings across all supported chains.

{
  "address": "0xYourWalletAddress",
  "chainIds": ["ethereum", "base", "arbitrum"]
}

get_tx_status

Check the status of a transaction.

{
  "txHash": "0xabc123...",
  "chainId": "base"
}

estimate_gas

Estimate gas for a swap transaction.

{
  "fromToken": "ETH",
  "toToken": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "amount": "1000000000000000000",
  "chainId": "base",
  "userAddress": "0xYourWalletAddress"
}

search_token

Search for tokens by name or symbol.

{
  "query": "USDC",
  "chainId": "base"
}

Environment Variables

| Variable | Default | Description | |----------|---------|-------------| | MCP_PORT | 3001 | HTTP server port | | MCP_TRANSPORT | http | Transport mode: http or stdio | | ONLYSWAPS_API_URL | - | OnlySwaps backend API URL | | ONLYSWAPS_API_KEY | - | API key for authenticated access | | CORS_ORIGINS | * | Comma-separated CORS origins | | PRIVY_APP_ID | - | Privy App ID (for execute_swap) | | PRIVY_APP_SECRET | - | Privy App Secret (for execute_swap) | | PRIVY_AUTHORIZATION_PRIVATE_KEY | - | Privy auth key (for execute_swap) |

Running Locally

# Install dependencies
pnpm install

# Build
pnpm build

# Run HTTP server
pnpm start

# Run stdio mode (for Claude Desktop)
node dist/index.js stdio

Docker

docker build -t onlyswaps-mcp .
docker run -p 3001:3001 \
  -e ONLYSWAPS_API_URL=https://api.onlyswaps.fyi \
  onlyswaps-mcp

API Endpoints

| Endpoint | Description | |----------|-------------| | GET /health | Health check | | GET /capabilities | Supported chains and tools | | GET /mcp | MCP SSE connection endpoint | | POST /mcp/messages | MCP message handler |

Links

• Website: https://onlyswaps.fyi
• Hosted MCP: https://mcp.onlyswaps.fyi
• GitHub: https://github.com/Delegueinu/onlyswaps

License

MIT