POST /v1/tx/swap

Builds an unsigned transaction to trade a token against a supported quote asset. This is the single endpoint for buys and sells.

• Auth: required (see API Authentication)
• Errors: see Errors

HTTP

• Method: POST
• Path: /v1/tx/swap

Headers

Authorization: Bearer api_your_key_here
Content-Type: application/json

How to Think About a Swap

Every swap has two sides:

• inputMint: the mint that goes into the DEX
• outputMint: the mint that comes out of the DEX

For most trades, one side is your token and the other side is one of the supported assets:

Asset	Mint
SOL	So11111111111111111111111111111111111111111
WSOL	So11111111111111111111111111111111111111112
USDC	EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v

Buy vs sell

Buying a token means the inputMint is SOL, WSOL or USDC and your token is outputMint.

Selling a token means your token is inputMint and the outputMint is SOL, WSOL or USDC.

Body

{
  "inputMint":  "<mint going into the DEX>",
  "outputMint": "<mint coming out of the DEX>",
  "amount":     0.1,
  "swapMode":   "exactIn",
  "slippage":   0.05,
  "priority":   "fast"
}

Fields

• inputMint (string, required): mint that goes into the DEX.
• outputMint (string, required): mint that comes out of the DEX.
• amount (number, required): Human unit amount for the side selected by swapMode.
• swapMode (string, required):
  • exactIn: amount is the exact input amount. Use this for most buys and sells.
  • exactOut: amount is the exact output amount. Use this when you need to receive exactly a specific amount.
• slippage (number, required): max allowed slippage as a decimal (0 ≤ slippage < 1). Example: 0.05 = 5%
• priority (string, required): see Priority (economy | fast | faster | fastest)

Response

{
  "success": true,
  "data": {
    "submissionToken": "txn_…",
    "unsignedTransaction": "BASE64_WIRE_TRANSACTION",
    "expiresAt": "2025-01-01T00:00:00.000Z",
    "platform": "pump_fun",
    "inputMint": "So11111111111111111111111111111111111111112",
    "outputMint": "TOKEN_MINT",
    "estimates": {
      "inputAmount": 0.1,
      "outputAmount": 3529922.965,
      "priceImpact": 0.00346
    },
    "priorityCost": 0.000005125
  }
}

Notes

• submissionToken links this built transaction for submission via POST /v1/tx/submit.
• inputMint / outputMint in the response match what you sent in the request.
• estimates are best-effort outputs assuming the market doesn’t move between build and execution.
• priceImpact shows how much your trade will move the price; 0.1 means ~10% price impact.
• priorityCost is the actual priority fee for this transaction. Check this before signing if you have cost limits.

Supported quote assets are SOL, WSOL and USDC.

Examples

Buy a token with SOL

Spend exactly 0.1 SOL to receive as many tokens as possible. The quote asset goes in, your token comes out.

{
  "inputMint":  "So11111111111111111111111111111111111111112",
  "outputMint": "TOKEN_MINT",
  "amount":     0.1,
  "swapMode":   "exactIn",
  "slippage":   0.05,
  "priority":   "fast"
}

Sell a token for SOL

Sell exactly 1 000 000 tokens and receive as much SOL as possible. Your token goes in, the quote asset comes out.

{
  "inputMint":  "TOKEN_MINT",
  "outputMint": "So11111111111111111111111111111111111111112",
  "amount":     1000000,
  "swapMode":   "exactIn",
  "slippage":   0.05,
  "priority":   "fast"
}

Buy a token with USDC

Spend exactly 10 USDC to buy a token on a USDC pair.

{
  "inputMint":  "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  "outputMint": "TOKEN_MINT",
  "amount":     10,
  "swapMode":   "exactIn",
  "slippage":   0.05,
  "priority":   "fast"
}