Avalonia remains MIT licensed and completely free. That’s not changing. What is changing is how we fund the development of new professional tooling built around the framework.
With Monday’s upcoming Accelerate update, we’re introducing a new licensing model for these tools that allows us to keep the core free while giving most of our community access to major upgrades at no cost.
We’re continuing to invest heavily in the open-source framework that benefits everyone. Alongside that, we’ve built a new generation of professional tooling, with 67% of users receiving free access through our new Community Edition. Enterprise users only need a licence if they want to use these new tools. For Visual Studio users, we’re also providing a six-month grace period (more on that later). And of course, you can keep using the existing MIT-licensed framework and legacy tooling exactly as before.
We know licensing changes are sensitive. This post explains exactly what’s changing, why, and how it affects you.
What’s Changing
We’ve spent thousands of hours building the Accelerate release from the ground up. The Visual Studio XAML service has been completely rewritten from scratch and we’re in the process of rewriting the previewer. Dev Tools is an entirely new application, not an update to the existing FOSS solution. Parcel is a brand new packaging tool built specifically to make packaging Avalonia applications as easy as possible. These tools aren’t forks or incremental updates. They’re completely new solutions providing significant improvements over what’s available today.
With this release, we’re introducing a Community Edition that provides free access to this new tooling for individuals, small organisations, and educational users. Our goal is simple: get these hugely improved tools into the hands of most of our users. Based on our telemetry, 67% of current users will be eligible for the Community License at no cost.
A note on TreeDataGrid: We announced in September 2024 that future TreeDataGrid development would continue as part of Accelerate as a commercial fork. The original FOSS version remains available on GitHub for anyone to use or fork. We’ll cover this in detail below, including how we’re recognising contributors to the original project.
Let’s be clear about what’s not changing: Avalonia UI itself remains entirely open-source under the MIT license. That’s not changing now, and it’s not changing in the future. You can continue building and shipping commercial applications with Avalonia completely free, forever.
What we’re licensing is the professional tooling and advanced UI components, not the framework itself.
Why We’re Making This Change
Earlier this year, Devolutions committed $3M to support Avalonia’s open-source development over three years. This funding is ring-fenced for FOSS work on the framework and areas that deliver broad community benefit. We’re using it to hire specialised engineers to work full-time on Avalonia. Professional tooling like the Visual Studio extension serves only part of our user base, so we’re directing the sponsorship towards more impactful areas that benefit everyone. And because the sponsorship runs for a fixed three-year term, we need to ensure that once it ends, we’re in a position to keep those engineers working with us. That means the tooling needs to be funded in other ways. Meanwhile, Avalonia has been the only .NET UI framework making its tooling open-source, despite receiving little in the way of community contributions to maintain it.
Given our commitment to keeping the core framework free and open-source for the entire community, the tooling is the most sensible place to introduce a commercial model. That’s why we’re introducing a complementary funding approach for our professional tools, which builds on Devolutions’ generous support and helps secure Avalonia’s long-term future.
I want to be clear though. Today’s announcement is fundamentally different from recent open-source licensing controversies. We are not altering or restricting the core framework’s licence. Avalonia UI remains MIT licensed. You can build and ship commercial applications with it, forever, for free. What we’re licensing is entirely new professional tooling we’ve built from scratch, not the framework itself.
Building these tools required significant investment. The Community Edition gives most of our users access to genuinely improved tools, massive upgrades over the existing FOSS options, at no cost. We’re asking larger commercial users to contribute to the project’s long-term viability.
This approach lets us continue investing in innovation and quality while keeping the core framework open and free for everyone.
Who This Affects (And How)
For Existing Accelerate Customers
Good news: you’re getting all of this included in your existing subscription. The completely rebuilt Visual Studio extension, brand new Dev Tools, new Parcel packaging tool, and the improved TreeDataGrid fork are all part of what you’re already paying for.
Even better: you’ll be grandfathered at your current pricing for future renewals until we deliver at least Phase 4 of Accelerate. This is our way of rewarding those who’ve supported us early and recognising your commitment to the Avalonia ecosystem.
For Individual Developers and Small Organisations
The Community Edition is brand new and free for you. This isn’t about restricting what was available. It’s about giving you access to significantly better tools than what exists today, at no cost.
Who’s eligible:
Individual developers working on their own equipment, including commercial projects
Small organisations (non-Enterprise) where up to five people can use the software concurrently
Educational and research institutions with unlimited users for teaching and academic research
An “Enterprise” is defined as an organisation with more than 250 users/PCs, or annual revenues exceeding €1,000,000.
What you get:
Access to the brand new Visual Studio extension, Dev Tools, and Parcel (with some features available in paid versions only)
Continued free use of the open-source Avalonia UI framework
No cost, ever
What’s not included:
Advanced UI components (WebView, Media Player, Markdown viewer, and the Accelerate TreeDataGrid)
Technical support
67% of current users will be eligible for the Community License at no cost, gaining access to tools that represent a massive upgrade over what’s available today.
For Enterprise Users
The Accelerate licence is entirely optional. I want to be completely explicit about this.
You can continue to use and ship with the existing tooling indefinitely.
The legacy FOSS Visual Studio extension remains available to clone and build at https://github.com/AvaloniaUI/AvaloniaVS.
The legacy Dev Tools source remains available.
The original TreeDataGrid remains available.
All are MIT licensed and can be used, forked, or maintained by anyone. While we’ve invested in creating significantly better options, the new licensing does not impact or change the existing (now legacy) options.
You only need an Accelerate licence if you want to use the new professional tooling. The ground-up rewrite of the Visual Studio extension, the entirely new Dev Tools app, or the new Parcel packaging tool.
If you choose to license Accelerate, you get:
The completely new Visual Studio extension (not a fork, built from scratch)
Brand new Dev Tools application (not an update, entirely new)
New Parcel packaging tool (purpose-built for Avalonia)
Advanced UI components (WebView, Media Player, Markdown viewer, and the improved TreeDataGrid)
Perpetual licences. You own them outright with no recurring fees
Know you’re contributing to the sustainability of Avalonia
Pricing:
We’ve listened to our customers and made changes based on what you told us. Our sales data showed a clear preference for perpetual licences over subscriptions. For every Indie subscription we sold, we sold 2.2 Business perpetual licences. With this release, we’ve dropped the Indie subscription tier entirely and focused on what you actually want: perpetual licences you own outright.
Business Licence: €219 (increased from €149)
Enterprise Licence: €599 (increased from €499)
Both licences are perpetual with no recurring fees.
Try Before You Buy
We’re offering a 30-day free trial starting Monday that includes all the functionality of our paid tools as well as all the pro UI components, including the On-Screen Keyboard. This gives you a chance to experience the full value of Accelerate before making any commitment.
We’re also providing a 6-month grace period for Visual Studio users. We understand that no one wants to open Visual Studio on Monday morning and be presented with unexpected licensing requirements they need to deal with. When you open VS, you want to work, not worry about procurement processes. We wanted to minimise any disruption to your day. That’s why the grace period doesn’t require signups or licence keys. Simply click “Skip until April 13th 2026” to keep using the new Visual Studio extension with full Community Edition access until then.
We hope this gives you time to:
Experience the value of the new tooling firsthand
Go through your organisation’s purchasing process
Make an informed decision about whether it’s worth the investment
If you decide it’s not right for you, you can continue using the legacy FOSS extension or switch to Visual Studio Code or JetBrains Rider, where the extensions remain freely available.
Support for Growing Startups
We recognise there’s a journey between being a small team and becoming an established enterprise. For privately held companies less than 5 years old with annual revenue or total institutional funding below €10M, we offer a 50% discount on Accelerate Enterprise through our Startup Program.
This creates an accessible pathway for growing companies. With the startup discount, the Enterprise licence (which includes the On-Screen Keyboard, email support, and source access for the Accelerate UI components) is just €299.50 per seat.
What if I don’t want any of this?
That’s completely fine. All the legacy tooling remains open-source and available on GitHub. The existing Visual Studio extension, Dev Tools, and TreeDataGrid code are still licensed under MIT. You can continue using them as they are today, or fork and maintain them independently if you prefer.
We put out a public call for maintainers to see if there was any interest from the community in continuing development of the FOSS versions, but there wasn’t. This reflects our broader experience that the most complex parts of the platform receive little in the way of meaningful contributions from outside the company.
TreeDataGrid: The Abridged Story
TreeDataGrid has been open-source on GitHub for years, but was never actually intended to be FOSS. It was always meant as a commercial component. There’s a rather long story behind why it ended up being released as FOSS, but we’ll save that for another day. The result of that decision was that it became extremely challenging to justify the opportunity cost of continued development, which predominantly fell on our CTO, Steven.
We opted to keep it FOSS, but set expectations that we would not review PRs or handle issues unless the reporter had an active Enhanced Support agreement. This made getting help with the control incredibly costly.
In September 2024, we announced that future development of the TreeDataGrid would continue as part of Accelerate. This isn’t a sudden change or a licence switch. It’s a commercial fork, which anyone is welcome to create themselves. That’s the beauty of FOSS.
To be clear, the original code remains MIT licensed, and anyone is free to maintain their own fork if they wish. We’re simply not continuing its development ourselves. We’ve developed our own fork and we’ll continue to develop it as part of Accelerate.
We understand this may be frustrating for some, especially for those who contributed to the original TreeDataGrid. We genuinely appreciate those contributions. They helped shape what the control became and informed our Accelerate version. As a token of our appreciation, we’ll be offering complimentary Enterprise subscriptions to select contributors who’ve played a key role in shaping the TreeDataGrid.
We also recognise the gap this creates. With the deprecation of DataGrid and the fork of TreeDataGrid, truly free options for displaying tabular data are limited.
That’s why with v12, we’re committing to a new control called ‘Table’. This will be a read-only way to display tabular data that will be entirely open-source and free to use. This will cover many use cases, though for complex datagrids with editing, sorting, and advanced features, users will need to either fork the existing FOSS TreeDataGrid or use one of the paid offerings available.
Our Commitment
We know this change will disappoint some users. We also believe this is the right path to ensure Avalonia continues to have a sustainable future, one where we can continue investing in both the open-source framework you rely on and the professional tooling that makes you more productive.
Avalonia UI remains open-source. The core framework that powers your applications isn’t changing. You can continue building and shipping commercial applications with it, forever, for free.
Stability is essential to us. We don’t make sudden or rushed changes because we understand that our users need long-term stability, not surprises. Stability isn’t just about software not crashing. It’s about how we operate, and how we’ll continue to operate. We want to be a trusted partner for the long term.
The 6-month grace period for Visual Studio users reflects that commitment. We announced the TreeDataGrid direction in September 2024, giving more than a year of notice. We don’t make abrupt changes that destabilise your work. We will always give you time to plan, evaluate, and make informed decisions.
We’re here to answer your questions. We know this is a significant change, and we’re committed to handling it as transparently and fairly as possible.
The Accelerate release goes live on Monday morning (CET). Community License registration will be available on our customer portal.
