POST /v1/tx/buy

Builds an unsigned transaction to buy a token with SOL.

• Mode: exactIn (you specify exact SOL in, token out is estimated)
• Auth: required (see API Authentication)
• Errors: see Errors

HTTP

• Method: POST
• Path: /v1/tx/buy

Headers

Authorization: Bearer api_your_key_here
Content-Type: application/json

Body

{
  "mint": "TOKEN_MINT",
  "solAmount": 0.002,
  "slippage": 0.05,
  "priority": "fast"
}

Fields

• mint (string, required): token mint address (Solana address)
• solAmount (number, required): SOL amount to spend
• slippage (number, required): 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": "So11111111111111111111111111111111111111111",
    "outputMint": "TOKEN_MINT",
    "estimates": {
      "inputAmount": 0.002,
      "outputAmount": 70598.459309,
      "priceImpact": 0.00346
    },
    "priorityCost": 0.000005125
  }
}

Notes

• submissionToken links this built transaction for submission via POST /v1/tx/submit.
• inputMint / outputMint are from the DEX perspective (what goes in vs what comes out).
• 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.