REST API Authentication

Authentication Guide

This guide covers:

• Overview - How authentication works and security model
• EIP-712 Signing - Step-by-step implementation with code examples
• Nonce Management - Best practices for nonce handling
• Examples - Complete SDK implementations in multiple languages
• Troubleshooting - Debug common authentication issues

REST EIP-712 Domain

All REST trading requests use the shared Synthetix EIP-712 domain:

{
  "name": "Synthetix",
  "version": "1",
  "chainId": 1,
  "verifyingContract": "0x0000000000000000000000000000000000000000"
}

This domain must be used when signing the action payloads documented in each REST trading method.