Introduction

Synthesis provides a single API to trade on prediction markets across Polymarket and Kalshi. Create wallets, place orders, stream real-time data, and manage positions — all through one integration.

Base URL

https://synthesis.trade

Quick links

Getting started

Create an account, set up a wallet, and place your first order.

Authentication

Learn about project API keys, session tokens, and account API keys.

Real-time data

Stream live balances, orderbooks, and trades via WebSockets.

API reference

Browse all available endpoints across Projects, Markets, Wallets, and more.

Response format

All API responses use a consistent envelope format.

{
    "success": true,
    "response": {
        "data": "..."
    }
}

{
    "success": false,
    "response": "Error message"
}

Authentication overview

The API uses three authentication methods depending on the type of request.

Auth Method	Header	Use Case	Routes
Project API Key	`X-PROJECT-API-KEY`	Backend account management	`/api/v1/project/*`
Session Token	`Authorization: Bearer ...`	Frontend user authentication	`/api/v1/account/`, `/api/v1/wallet/`
Account API Key	`X-API-KEY`	Backend user operations	`/api/v1/account/`, `/api/v1/wallet/`

Learn more about authentication

See detailed examples for each authentication method.

Overview

Getting Started

Authentication

Real-time Data

Base URL

Quick links

Getting started

Authentication

Real-time data

API reference

Response format

Authentication overview

Learn more about authentication

​Base URL

​Quick links

Getting started

Authentication

Real-time data

API reference

​Response format

​Authentication overview

Learn more about authentication

Base URL

Quick links

Response format

Authentication overview