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io.github.Swap-API/mcp

Official registry Finance and payments

MCP server for SwapAPI - get executable token swap calldata for EVM chains

Source code Documentation

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).

NPM package @swapapi/mcp
Claude Code 
claude mcp add io-github-swap-api-mcp -- npx -y @swapapi/mcp@0.1.0
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "io-github-swap-api-mcp": {
            "command": "npx",
            "args": [
                "-y",
                "@swapapi/mcp@0.1.0"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. Swap API
  2. Quick Start
  3. Example Response
  4. API Reference
  5. More Curl Examples
  6. Executing Swaps
  7. MCP Server
  8. OpenAPI Spec
  9. Limits
  10. License

Swap API

Executable token swap calldata in one GET request. No API keys. No accounts. No SDK bloat.

https://api.swapapi.dev

Quick Start

Swap 1 ETH for USDC on Ethereum:

curl "https://api.swapapi.dev/v1/swap/1?\
tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
tokenOut=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&\
amount=1000000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

That's it. The response contains everything you need to sign and broadcast.

Example Response

{
  "success": true,
  "data": {
    "status": "Successful",
    "tokenFrom": {
      "address": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE",
      "symbol": "ETH",
      "name": "Ether",
      "decimals": 18
    },
    "tokenTo": {
      "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
      "symbol": "USDC",
      "name": "USD Coin",
      "decimals": 6
    },
    "swapPrice": 2435.12,
    "priceImpact": 0.0003,
    "amountIn": "1000000000000000000",
    "expectedAmountOut": "2435120000",
    "minAmountOut": "2422947280",
    "tx": {
      "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
      "to": "0x011E52E4E40CF9498c79e329EBc29ed08c8B5abB",
      "data": "0x2646478b...",
      "value": "1000000000000000000",
      "gasPrice": 30000000000,
      "gas": "250000"
    }
  },
  "timestamp": "2026-03-12T00:00:00.000Z"
}
FieldDescription
successBoolean indicating request success
data.status"Successful", "Partial", or "NoRoute"
data.tokenFrom/tokenToToken metadata (address, symbol, decimals)
data.swapPriceExchange rate
data.priceImpactSlippage impact (0.001 = 0.1%)
data.expectedAmountOutEstimated output in token's smallest unit
data.minAmountOutGuaranteed minimum (respects your maxSlippage)
data.txTransaction object ready to sign and send

API Reference

Endpoint: GET /v1/swap/{chainId}

Parameters:

ParamRequiredDescription
chainIdpathChain ID (1=Ethereum, 8453=Base, 42161=Arbitrum, etc.)
tokenInqueryInput token address. Use 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE for native ETH
tokenOutqueryOutput token address
amountqueryInput amount in smallest unit (e.g., wei for ETH)
senderqueryYour wallet address (used to build the tx)
maxSlippagequeryOptional. 0-1 (default: 0.005 = 0.5%)

Response codes:

  • 200 — Quote ready
  • 400 — Invalid params or unsupported chain
  • 429 — Rate limit exceeded (60/min per IP)
  • 502 — Upstream service error

More Curl Examples

Base (ETH → USDC)
curl "https://api.swapapi.dev/v1/swap/8453?\
tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
tokenOut=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&\
amount=500000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
Arbitrum (USDC → ETH with 1% slippage)
curl "https://api.swapapi.dev/v1/swap/42161?\
tokenIn=0xaf88d065e77c8cC2239327C5EDb3A432268e5831&\
tokenOut=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
amount=1000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&\
maxSlippage=0.01"
Ethereum Mainnet (DAI → USDC)
curl "https://api.swapapi.dev/v1/swap/1?\
tokenIn=0x6B175474E89094C44Da98b954EedeAC495271d0F&\
tokenOut=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&\
amount=1000000000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
Polygon (MATIC → USDC)
curl "https://api.swapapi.dev/v1/swap/137?\
tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\
tokenOut=0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174&\
amount=10000000000000000000&\
sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

Executing Swaps

The API gives you an unsigned transaction. Sign it and broadcast:

With Foundry cast
# 1. Set swap parameters
CHAIN_ID=8453
TOKEN_IN=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
TOKEN_OUT=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
AMOUNT=1000000000000000000
SENDER=0x...        # Your address
PRIVATE_KEY=0x...   # Your private key
RPC_URL=https://mainnet.base.org

# 2. Get swap quote
RESPONSE=$(curl -s "https://api.swapapi.dev/v1/swap/$CHAIN_ID?\
tokenIn=$TOKEN_IN&\
tokenOut=$TOKEN_OUT&\
amount=$AMOUNT&\
sender=$SENDER")

# 3. Parse the tx fields
TX_TO=$(echo "$RESPONSE" | jq -r '.data.tx.to')
TX_DATA=$(echo "$RESPONSE" | jq -r '.data.tx.data')
TX_VALUE=$(echo "$RESPONSE" | jq -r '.data.tx.value')
TX_GAS=$(echo "$RESPONSE" | jq -r '.data.tx.gas')

# 4. Sign and send
cast send \
  --rpc-url "$RPC_URL" \
  --private-key "$PRIVATE_KEY" \
  "$TX_TO" \
  --value "$TX_VALUE" \
  --gas-limit "$TX_GAS" \
  --data "$TX_DATA"
With viem
import { createWalletClient, http } from 'viem'
import { privateKeyToAccount } from 'viem/accounts'
import { base } from 'viem/chains'

const account = privateKeyToAccount('0x...')

const client = createWalletClient({
  account,
  chain: base,
  transport: http()
})

const response = await fetch(
  'https://api.swapapi.dev/v1/swap/8453?' +
  'tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&' +
  'tokenOut=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&' +
  'amount=1000000000000000000&' +
  'sender=' + account.address
)

const { data } = await response.json()

const hash = await client.sendTransaction({
  to: data.tx.to,
  data: data.tx.data,
  value: BigInt(data.tx.value),
  gas: BigInt(data.tx.gas)
})

await client.waitForTransactionReceipt({ hash })

MCP Server

For AI agents, Claude Desktop, Cursor, Cline, and other MCP clients:

npx @swapapi/mcp

Or add to Claude Desktop config:

{
  "mcpServers": {
    "swapapi": {
      "command": "npx",
      "args": ["@swapapi/mcp"]
    }
  }
}

See mcp/README.md for full MCP documentation.

OpenAPI Spec

See openapi.json for the full OpenAPI specification.

Limits

  • Rate limit: 60 requests/minute per IP
  • No authentication required
  • Free to use

License

MIT

Frequently asked questions

What is io.github.Swap-API/mcp?

MCP server for SwapAPI - get executable token swap calldata for EVM chains

How do I install io.github.Swap-API/mcp?

It runs on your machine. In Claude Code: claude mcp add io-github-swap-api-mcp -- npx -y @swapapi/mcp@0.1.0. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.Swap-API/mcp 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 io.github.Swap-API/mcp open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.github.Swap-API/mcp?

It is published by swap-api. 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.