TopStep Simulator API

The TopStep Simulator API is a faithful emulation of the TopStep ProjectX Gateway API. It exposes the same endpoints, request/response formats, and enum values so that strategies built for TestMax can be ported to live trading on TopStep with minimal code changes.

In addition to the standard ProjectX endpoints, TestMax adds Replay Control endpoints that allow you to start backtest sessions, step through historical bars, control playback speed, and retrieve final results. These replay endpoints are the key differentiator that turns a trading API into a backtesting engine.

Base path

All TopStep Simulator API endpoints are prefixed with:

https://api.test-max.com/api/topstep-sim/

For example, to place an order:

POST https://api.test-max.com/api/topstep-sim/Order/place

Authentication

The Simulator API uses Bearer token authentication. You must first obtain a token by calling Auth/loginKey with your email address and API key, then include the token in the Authorization header of all subsequent requests.

Authorization: Bearer <your-token>
Content-Type: application/json

See the Authentication page for the complete flow.

Endpoint reference

Auth

Method	Endpoint	Description
POST	Auth/loginKey	Authenticate with email and API key
POST	Auth/validate	Validate or refresh an existing token
POST	Auth/logout	Invalidate a token
GET	Status/ping	Health check

Account

Method	Endpoint	Description
POST	Account/search	List trading accounts

Contract

Method	Endpoint	Description
POST	Contract/search	Search for instruments by name or symbol
POST	Contract/searchById	Find a specific contract by ID

Order

Method	Endpoint	Description
POST	Order/place	Place a new order (market, limit, stop, or stop-limit)
POST	Order/search	Search all orders for an account
POST	Order/searchOpen	Get open/pending orders only
POST	Order/cancel	Cancel a pending order
POST	Order/modify	Modify a pending order’s size or price

Position

Method	Endpoint	Description
POST	Position/searchOpen	Get all open positions
POST	Position/closeContract	Close an entire position
POST	Position/partialCloseContract	Partially close a position

Trade

Method	Endpoint	Description
POST	Trade/search	Get trade/fill history

Replay Control (TestMax extension)

Method	Endpoint	Description
POST	Replay/start	Start a new backtest session
POST	Replay/step	Advance the replay by N bars
POST	Replay/jumpTo	Jump to a specific timestamp
POST	Replay/play	Start auto-playing at a given speed
POST	Replay/pause	Pause auto-play
POST	Replay/end	End the session and get final results

Note

The Replay Control endpoints are a TestMax extension not present in the real TopStep ProjectX Gateway. When porting a strategy to live trading, you replace the replay loop with a real-time WebSocket data feed. See TopStep Compatibility for guidance.

History

Method	Endpoint	Description
POST	History/retrieveBars	Retrieve historical OHLCV bars

Typical workflow

A complete backtest session follows this sequence:

1. Authenticate — POST Auth/loginKey
2. Get account — POST Account/search
3. Find contract — POST Contract/search
4. Start replay — POST Replay/start with instrument, date, and timeframe
5. Main loop — POST Replay/step to advance bars, POST Order/place to trade, POST Position/searchOpen to check positions
6. End session — POST Replay/end to finalize and get P&L results

Detailed endpoint documentation

Authentication Login, token validation, and logout

Accounts Search and manage trading accounts

Contracts Search for instruments and contracts

Orders Place, search, modify, and cancel orders

Positions Query and close open positions

Trades Query trade and fill history

Replay Control Start, step, play, pause, and end sessions

History & Bars Retrieve historical OHLCV bar data