Frequently Asked Questions

Frequently Asked Questions


  • What is Flax Engine?
  • Flax Engine is a complete suite of game development tools made by game developers, for game developers. Our goal is to create the most powerful game engine in the industry and to give creators all across the globe the tools to harness this power to create world-class gaming experiences, no matter their budget or team size.
  • What are the Flax system requirements?
  • You can find the Flax Engine system requirements on the Requirements page in the Flax manual.
  • What platforms can I make applications for using Flax?
  • Flax currently supports Windows, Xbox One and Universal Windows Platforms (UWP). Support for Android, iOS, Mac, PlayStation 4 and Switch will come later. You can find more info on the Platforms page in the Flax manual.
  • Is there a roadmap of coming Flax features?
  • Yes! You can find the Flax roadmap here. It’s updated weekly.
  • Is Flax free?
  • Flax is free for uncommercial and educational usage. When you’re making a commercial product you have to pay a 4% royalty after you game earn $3,000 per calendar quarter. For more information about license see this licensing page.
  • I’m a consultant. Do I owe royalties on consulting fees?
  • No, you don’t.
  • Can I create videos or streams and use them to generate YouTube ad revenue or Twitch donations?
  • Yes. No royalty is owed on this revenue.
  • Can I get a full engine source (including C++ core)?
  • If you need an access to whole Flax Engine source code contact with us. Check custom licensing page for more information about it.

Release and Licensing

  • What kinds of products can I release with Flax Engine?
  • You can create and release any product that is allowed by law, with the exception of gambling applications and certain safety-critical control systems described in the EULA. You can release games, demos, VR projects, architectural showcases, trailers, films, and more.

    The only parts of the Flax Engine you can’t release to the general public are the source code and tools or modifications to them; these components may only be distributed to other licensees with access to the same version of the Flax Engine.
  • What do I have to do when releasing a product?
  • You’re obliged to notify Flax before release and send a revenue with notifying after your product earns money. See here for more details.
  • What royalties do I have to pay and when?
  • In general, you have to pay to Flax 4% of all gross revenue after the first $3,000 per game per calendar quarter, regardless of what the company collects the revenue.

    For example, if your product earns $100 from sales on the App Store, the royalty due is $4 (4% of $100), even though you would receive roughly $70 from Apple after they deduct their distribution fee of roughly $30 (30% of $100). Royalty payments are due 45 days after the close of each calendar quarter. Along with the payment, you must send a royalty report on a per-product basis. For more information, see here.
  • What about downloadable content, in-app purchases, microtransactions, virtual currency redemption, and subscription fees, as well as in-app advertising and affiliate program revenue?
  • Revenue from these sources is included in the gross revenue calculation above.
  • How long do I have to report royalties?
  • You only need to report royalties when you are making more than $3,000 per quarter from your product. If your game no longer is being sold, or no longer makes that amount of money, no royalty reports are due.
  • What if I need custom licensing terms?
  • If your project requires dedicated terms that reduce or eliminate the 4% royalty in exchange for an upfront fee, or if you need custom legal terms or dedicated Flax support to help your team reduce risk or achieve specific goals, we’re here to help. See the custom licensing page for details.
  • What if my product is released through a publisher or distributor?
  • You’re free to release Flax Engine products through a publisher or distributor, and the EULA gives you the right to sublicense the necessary parts of the Flax Engine to them so they can release your game.

    When negotiating terms with publishers, please keep in mind that the royalty remains 4% of the product’s gross revenue after the first $3,000 per game per calendar quarter from users. In this scenario, feel free to refer your publisher to Flax during discussions, as it may be advantageous to all if the publisher obtains a custom-negotiated, multi-product Flax Engine license covering your product.
  • What if my project wins cash award?
  • You do not have to pay royalties on award winnings.
  • What if my product obtains crowdfunding via Kickstarter or another source?
  • Royalties are due on revenue from Kickstarter or other crowdfunding sources when the revenue is actually attributable to your product. For example, if the user is required to purchase a particular funding package to obtain access (now or later) to your product, or if that package gives the buyer benefits within the product such as in-game items or virtual currency.

    Here’s an example of what we mean by “attributable”: Assume you provide two tiers of offers, a signed poster for $20, and a signed poster plus game access for $50. No royalties are due on ancillary products like posters, so no royalty is due on the $20 tier. On the $50 tier, the user is paying for the poster with a $20 value, and that implies that the remaining $30 of value is attributable to the product. So, for each $50 tier sale, you’d pay a royalty of $1.2 (4% of $30).
  • What are the royalty-free options?
  • You can use Flax Engine for totally free for the following:
    • Creating video tutorials
    • Educational usage (including all academic institutions)
    • Truly free games and apps (with no associated revenue)
    • Non-interactive linear media, including movies, animated films and cartoons distributed as video.
    • Amusement park rides and live installations.
    • Consulting and work-for-hire services using the engine. This applies to architects using the engine to create visualizations as well as consultants receiving a development fee.
    • Merch products, including t-shirts, CDs, plushies, action figures, and books. The exception is items with embedded data or information, such as QR codes, that affect the operation of the product.


  • Where I can find engine source code?
  • C# scripting API, as well as Flax Editor, are available to access here and licensed under Flax EULA.
    Flax Engine C++ code is not released to the public but may be accessed after signing a custom license. More details here.
  • Can I share code snippets online?
  • Flax Engine licensees are permitted to post engine code snippets (up to 30 lines) in a public forum, but only for the purpose of discussing the content of the snippet.
  • How can I contribute to Flax?
  • We welcome any contributions to Flax Engine development through pull requests on GitHub (here). Most of our active development is in the master branch, so we prefer to take pull requests there (particularly for new features). We try to make sure that all new code adheres to the Flax coding standards. All contributions are governed by the terms of the EULA.
  • How do I submit FlaxAPI or Flax Editor code changes back to Flax?
  • We use Github channel so a growing number of contributors can fork and modify parts of the engine code. Any source code changes you check in at GitHub will be visible to the community. If you submit a pull request to Flax, we’ll review it and consider inclusion of your code into mainline Flax Engine. If we ship your contribution, we’ll gladly add your name to the credits in the engine.
  • Can I request a feature?
  • Yes! Post it on forums or send it directly via contact form. Also check out our public roadmap.