arb-dex-mcp

An MCP server that gives an AI agent live cross-DEX market data on six EVM chains — BSC, Polygon, Arbitrum, Base, Avalanche and Optimism.

Every number is read from on-chain pool state at a stated block: per-venue pool price, pool TVL, and the gross cross-venue spread with the optimal trade size that captures it. Nothing is modelled, estimated or backfilled, and each payload carries its own scope note — so an agent that quotes a figure also has the caveats attached to it.

Backed by the Multi-Chain DEX Prices & Liquidity API.

Tools

Without a key the server still runs and returns real data from the free public surface, labelled as such. It never fabricates a row or silently degrades: a paid call with no key returns an explicit key-required error with the signup link.

Spreads are gross — before gas, MEV and slippage beyond the optimal size. Not a profit estimate and not trade advice. A wide spread against a shallow pool is worth very little, and get_spreads says so per row rather than letting a big basis-point number mislead.

Related MCP server: ProfitSpot MCP

Install

git clone https://github.com/donnywin85/arb-dex-mcp.git
cd arb-dex-mcp
npm install

Requires Node 18+.

Get a key

The paid tools call the API through RapidAPI using your own key. This package ships no credentials of any kind.

1. Subscribe (there is a free tier): https://rapidapi.com/donnydev/api/multi-chain-dex-prices-liquidity

2. Copy your X-RapidAPI-Key from the RapidAPI dashboard.

3. Put it in RAPIDAPI_KEY in the config below — never in code, and never in a commit.

Claude Desktop

claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "arb-dex": {
      "command": "node",
      "args": ["/absolute/path/to/arb-dex-mcp/src/index.mjs"],
      "env": {
        "RAPIDAPI_KEY": "your-rapidapi-key-here"
      }
    }
  }
}

Restart Claude Desktop; the four tools appear under the connectors icon.

Claude Code

claude mcp add arb-dex --env RAPIDAPI_KEY=your-rapidapi-key-here -- node /absolute/path/to/arb-dex-mcp/src/index.mjs

Then /mcp to confirm it connected.

Try it

Ask your agent:

• "Which chains and DEX venues does arb-dex cover?"

• "What is WBNB/USDT trading at on every BSC venue right now?"

• "Show me the cross-DEX spreads on Polygon — are any actually capturable?"

• "Run a live spread sweep on Arbitrum and rank by gross USD."

Configuration

See .env.example.

Test

npm run selftest                    # keyless: exercises the free fallbacks
RAPIDAPI_KEY=... npm run selftest   # keyed: exercises the paid routes

The test spawns the server over stdio and calls every tool against the real production API — nothing is mocked. It asserts on live values (block number, per-venue prices, scanned-pair counts), so a run that passes is evidence the data path works end to end.

Known gap

The API's paid measurement archive (/v1/history/*) is live on the origin but is not yet registered on the RapidAPI listing, so calls through the proxy 404. A get_history tool is therefore deliberately absent rather than shipped broken; it lands once the listing exposes those routes.

License

MIT