RmlUi Developer Survey 2026 – Results

[mikke89]

Here are the results from the RmlUi Developer Survey 2026, which was mainly posted about in the RmlUi 6.2 release notes.

I'm thrilled to see so many taking the time to answer the survey. Going in, I had no idea if I'd get any responses, or whether respondents would take it seriously. Now I can say though, we certainly got a lot of really great answers. I feel I have a completely different understanding now over what users value, how they are using the library, and what they want the library to prioritize. It's been really fun, I'm so glad to have done this, and really happy with the community. Cheers!

In the following you'll find statistics from the answers to all the survey questions. I am adding some of my own comments throughout the results. I hope you find it interesting like I did.

/Michael

---

Survey open: January 11 – February 1
Total responses: 50
Full responses: 23
Incomplete responses: 27

---

Table of Contents

• 1. How are you using RmlUi?
• 2. For how long have you used RmlUi?
• 3. What kind of project do you use RmlUi for?
• 4. Have you released any project with RmlUi?
• 5. I am using RmlUi for
• 6. How much experience do you have as a hobbyist developer?
• 7. How much experience do you have as a professional developer?
• 8. How much do you value the following aspects in RmlUi?
• 9. How well would you say the following traits apply to RmlUi?
• 10. Which areas of RmlUi would you most want to see improvements?
• 11. How important is backward compatibility to you?
• 12. Which features do you currently use?
• 13. Which input devices do you support or want to support?
• 14. Which backend(s) are you using?
• 15. Which features or improvements would you be most interested in for your project?
• 16. Comments

1. How are you using RmlUi?

2. For how long have you used RmlUi?

3. What kind of project do you use RmlUi for?

4. Have you released any project with RmlUi?

Author comments:

• We got several comments about some very interesting projects, thank you! I am not posting the answers directly here to ensure not to identify anyone without their consent. If you want your project listed, please post the projects on the thirdparty resources thread, and I'll add it to the list there.

5. I am using RmlUi for

Multiple selections allowed

6. How much experience do you have as a hobbyist developer?

7. How much experience do you have as a professional developer?

8. How much do you value the following aspects in RmlUi?

The philosophy of RmlUi is to provide a highly customizable user interface that can be easily integrated into any engine, based on the HTML and CSS standards. We prioritize being lightweight and performant rather than trying to support all features, and we add novel features where they make sense. The following lets you specify which of these aspects are important to you.

Author comments:

I found this very interesting for multiple reasons:

• Users overall seem to agree with the philosophy of the library, which is a nice confirmation.
• People love performance. It's not too surprising, any user interface to be taken seriously should be fast and snappy. Anything else massively impacts the user experience. And seeing that we have a lot of gaming-focused developers, there is only so much available resources that can be dedicated to the user interface.
• Developers seem to prefer HTML/CSS features over custom features. It makes sense to me, familiarity helps development speed, and there are just so many helpful resources on the web which no smaller C++ library could ever match. Benefitting from these resources is a massive boost to the library.
  • Generally, we try to follow the HTML/CSS standard for new features, unless we have some specific requirements. These answers also make me more comfortable to slightly change existing behavior in the direction of HTML/CSS.

9. How well would you say the following traits apply to RmlUi?

10. Which areas of RmlUi would you most want to see improvements?

Author comments:

• Performance, I hear you! I don't normally see many issues or feedback around this, so I'm glad this is coming out of this survey. I do wonder if users have specific performance issues, or there is a more general feeling.
  • Call to action: If you have some specific performance situation that's causing friction, please make a new issue! For more general thoughts around this, please leave some comments, I'd love to understand better.
  • The previous questions showed that most users are generally happy about the performance though, so it could mainly be a trait that is very highly valued compared to the other entries here. Let me know!
• Similarly, for those that experience bugs or issues with HTML/CSS conformance, I'd like to hear more about this. Please make an issue or comment.
• When filtering on experienced RmlUi users (1 year+, not shown), there is a somewhat higher desire for performance improvements and features, while significantly less emphasis on samples, documentation, and ease of integration.
  • As a library author, there is a balancing act between on-boarding new users, and adding more advanced features and performance improvements for experienced ones. I think it helps everyone that we get fresh eyes on things regularly, so in my view we should keep spending some efforts to improve how easy it is to get started.

11. How important is backward compatibility to you?

Consider when there is a conflict between backward compatibility and an improvement.

Author comments:

• The general consensus is to favor improvements over backward compatibility. However, there are some users that prefer backward compatibility.
• We should try to accommodate the minority here too, but we cannot let backward compatibility completely stop the health of the project long-term. It's a difficult trade-off, and every situation is a bit different.
• Up to now I have been changing things up now and then, mainly around major version changes, while ensuring good documentation of breaking changes with detailed upgrade guides. I think this gives me the backing to continue this approach.

12. Which features do you currently use?

Author comments:

• Wow, practically everyone uses flexbox.
• Runner-up features are animations, transforms, and rounded boxes. These are classic features the library was essentially founded on.
• I am quite surprised to see box shadows so widely used, being a relatively new feature.
• Huh, the SVG plugin is quite popular too! Nice, I guess it makes sense, given its support on the web.
• I just find these tables so cool to see. I'm glad to see all of these features being used by someone. The results really help prioritize where efforts should best be spent, or if some features should be reconsidered.

13. Which input devices do you support or want to support?

Multiple selections allowed

Other (comments)

• Non-gamepad joysticks, sensors (such as gamepad accelerometers and gyroscopes).

14. Which backend(s) are you using?

Multiple selections allowed

Author comments:

• A lot of users are writing custom backends, perhaps more-so than I would have thought. It's nice to see that people are taking advantage of the customizability of the library.
• Some of the custom backends include (based on comments): Custom OpenGL3, DirectX 9, DirectX 11, Godot, Source engine's CMeshBuilder, BGFX, custom SDL_GPU, Unreal Engine, native Wayland.
• The most popular ones are SDL_GL3 and GLFW_GL3. These are solid choices, OpenGL3 being the reference implementation with all the features.
• No love for X11 and SFML in this survey. It could be a sign to retire them.
• I wonder if the SDLrenderer has much of a purpose now that SDL_GPU exists. However, some are still using the former, would be interested to better understand why.

15. Which features or improvements would you be most interested in for your project?

Author comments:

• There's a lot of spread around these features. I really had no idea what I would see from this list going in, really interesting. Will be really helpful when considering features to implement.
• Everyone wants better performance (yes!). I have been working on caching for some time now, so it's nice to see the desire for it!
• As a maintainer, I also need to consider the complexity and effort of each feature, also in terms of long-term maintenance. Not to mention the performance implication of each feature, which users clearly care about.

16. Comments

Feel free to write any comments or feedback on the RmlUi library.

Author comments:

We got 13 comments. Here is a quick summary:

• A lot of praise, thank you all!
• Backends wanted: DirectX 9, DirectX 11, DirectX 12, Metal (with SDL), Unreal Engine 5.
• Rust bindings and JavaScript plugin.
• (Multichannel) SDF support.
• Improving RCSS defaults or user-agent stylesheet. Difficulty setting up scrolling.
• A sample for world space UI. [Would be a cool one, any volunteers?]
• "It's a breeze to integrate with the Godot Engine".

That's it!

Thanks for all your answers to the survey. Did you find something of particular interest from the results, or any surprises? Share your thoughts or feedback, either about the library or the survey. Cheers!