JetBrains removes commercial license for its LSP API

Back in July, JetBrains announced that it was changing how it distributes IntelliJ IDEA, bringing in a so-called "unified distribution" model. This means that starting with version 2025.3, the company will start shipping a single unified installer instead of separate ones for its paid Ultimate and free Community editions.

Users with an expired subscription will drop into a fallback mode, a free tier of the IDE with a baseline set of features. Now, the company has announced several changes to the Language Server Protocol (LSP) API in its IDEs.

First of all, the LSP API will be available for free, though JetBrains says it is part of a "limited feature set" in this new fallback mode, starting with version 2025.2. This change happens right before the full unified distribution kicks in with 2025.3.

If you are a plugin developer, this means your LSP-based plugins can now reach users who do not have an active Ultimate subscription. The flip side is that the free Community Edition, which is still around for 2025.2, will lose its LSP support before it gets discontinued entirely.

JetBrains says that you should not expect the LSP API to be a complete replacement for its Program Structure Interface (PSI), which, if you do not know, is the deeply integrated system that parses source code into a detailed structural tree.

This PSI tree is what powers almost every advanced feature in a JetBrains IDE, from complex refactoring to code analysis. It offers incredible depth but requires a ton of effort to implement for a new language.

There are also things to consider like performance, as LSP's client-server model can introduce communication overhead that a native PSI implementation should not have.

For what it is worth, the API in the IntelliJ platform already offers things like rich code completion with resolve support, go to definition, hover documentation, and diagnostics. The implementation also supports more advanced capabilities like code actions, quick-fixes, and document formatting.

Developers who want to get started will need to target IntelliJ IDEA Ultimate 2025.2.1 or newer and declare an optional dependency on the "com.intellij.modules.lsp" module.