You get $100,000 in margin capacity, and that's set by the exchange's initial margin requirements, not an arbitrary limit. At current rates that works out at roughly three ES contracts or two NQ at one time. Margin requirements are set by CME and change periodically, so the exact number will vary.
Some products carry much higher margin requirements - Bitcoin being the obvious example, where a single full contract would take up most of your capacity. In those cases micro contracts give you far more room to size properly.
This structure is designed to mirror real market constraints, allowing us to evaluate how you manage genuine risk - not just work around artificial caps.
Initial margins for each contract are published on the relevant exchange website - the ES margins are here: CME Group ES Margins.
If you have any questions, please reach out to support@developtraders.com.