Build and return transaction data ready for signing or submission. This endpoint constructs
blockchain transactions based on your parameters and returns either signed or unsigned
transaction strings.

⚠️ ENCRYPTION REQUIRED

This endpoint requires AES-256-GCM encrypted request bodies.

All requests must be encrypted using your API credential's encryption key.
See the Request Encryption section in the Transactions tag description above for implementation details.

Request Headers:

Content-Type: text/plain
X-Encrypted: true

Response Headers:

• X-Server-Signature: HMAC-SHA256 signature of response body (verify this!)

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Response Modes

Signed Transactions (with privateKey)

When you include privateKey in the wallets object, the API returns signed transactions
in the result field, ready for submission.

Unsigned Transactions (without privateKey)

When you omit privateKey, the API returns unsigned transactions in the
unsignedTransactions field. Sign these client-side using your wallet or hardware device,
then submit via /transaction endpoint.

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Usage Notes

• Transactions are built but NOT submitted to the blockchain
• Automatically calculates optimal gas/priority fees if not specified
• Validates transaction parameters before building
• Handles token approvals automatically when needed (EVM chains)
• When exchange: "jupiter", only Solana is supported

Accessibility

Tier Access: Starter, Pro, Enterprise

Compute Unit Cost: 10 CU per request

Chain Supported

Anti-MEV Provider Support

Transaction Types

Swap Transactions

Immediate token-to-token exchanges with configurable slippage and optional MEV protection.

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Common Use Cases

• Pre-build transactions for later submission
• Create unsigned transactions for hardware wallet signing
• Build complex multi-transaction strategies
• Test transaction parameters without submitting
• Implement approval workflows requiring user confirmation

Best Practices

• Always encrypt requests - Unencrypted requests will be rejected
• Verify response signatures - Check X-Server-Signature header
• Validate wallet balances before building transactions
• Set appropriate priority fees based on network congestion
• Test with small amounts before executing large transactions
• Submit built transactions promptly (they may expire on some chains)
• Consider gas/fee costs in your profit calculations
• Prefer unsigned transactions for maximum security (never send private keys)

Security Considerations

• All requests must be encrypted with your encryption key
• Verify all response signatures before processing
• Consider using unsigned transaction mode (omit privateKey)
• Never share signed transaction strings publicly
• Implement transaction amount limits
• Validate all parameters before building
• Set transaction expiration times appropriately