If Rithmic is the old guard, TopstepX is the newer one, and it feels it. Under the hood it’s the ProjectX Gateway API — a modern REST interface plus a realtime hub for live updates. After wrestling with lower-level protocols, that’s a relief: it’s the kind of API you can reason about.
Two channels matter when you wire a bot to it. There’s a realtime stream that pushes order and trade updates as they happen — we see a fill the moment it fills — and a REST surface you poll for the slower-moving truth: open positions and the account’s realized P&L. Knowing which is which is the whole game.
Because the split is real, you have to design around it. Order events arrive live, but the authoritative account number is a REST read. So our TopstepX bots run a reconcile loop: take the live fills for responsiveness, then true them up against the account endpoint so the P&L on your screen is the same number the firm is using to judge you. (For contrast, our Rithmic side is fussier here — different plumbing, different trust model — which is exactly why we don’t assume one integration behaves like another.)
What you don’t get for free is the thing nobody gets for free: a clean intraday bar feed. The gateway is built around orders and account state, not historical candles for backtesting. So we do the same thing we do everywhere — the bot streams the 1-minute bars it already computes to trade, and those are what the dashboard charts. Real bars, perfectly aligned with the fills that happened on them.
A few notes from running it live: order updates are clean and fast, so lean on them for anything that needs to feel instant. Positions and P&L are eventually-consistent — treat them as state you poll, not events you trust blindly. Build your monitoring as “live for events, poll for state” and TopstepX behaves itself.
The lesson is the one we keep relearning: pick an integration for its API surface, not its logo. TopstepX’s REST-plus-realtime gateway made the wiring straightforward. The actual work was never the protocol — it was deciding what to trust live and what to confirm on a poll.