1# Developing Extensions
2
3## Extension Features
4
5Extensions are able to provide the following features to Zed:
6
7- [Languages](./languages.md)
8- [Debuggers](./debugger-extensions.md)
9- [Themes](./themes.md)
10- [Icon Themes](./icon-themes.md)
11- [Slash Commands](./slash-commands.md)
12- [MCP Servers](./mcp-extensions.md)
13
14## Developing an Extension Locally
15
16Before starting to develop an extension for Zed, be sure to [install Rust via rustup](https://www.rust-lang.org/tools/install).
17
18> Rust must be installed via rustup. If you have Rust installed via homebrew or otherwise, installing dev extensions will not work.
19
20When developing an extension, you can use it in Zed without needing to publish it by installing it as a _dev extension_.
21
22From the extensions page, click the `Install Dev Extension` button (or the {#action zed::InstallDevExtension} action) and select the directory containing your extension.
23
24If you need to troubleshoot, you can check the Zed.log ({#action zed::OpenLog}) for additional output. For debug output, close and relaunch zed with the `zed --foreground` from the command line which show more verbose INFO level logging.
25
26If you already have the published version of the extension installed, the published version will be uninstalled prior to the installation of the dev extension. After successful installation, the `Extensions` page will indicate that the upstream extension is "Overridden by dev extension".
27
28## Directory Structure of a Zed Extension
29
30A Zed extension is a Git repository that contains an `extension.toml`. This file must contain some
31basic information about the extension:
32
33```toml
34id = "my-extension"
35name = "My extension"
36version = "0.0.1"
37schema_version = 1
38authors = ["Your Name <you@example.com>"]
39description = "My cool extension"
40repository = "https://github.com/your-name/my-zed-extension"
41```
42
43In addition to this, there are several other optional files and directories that can be used to add functionality to a Zed extension. An example directory structure of an extension that provides all capabilities is as follows:
44
45```
46my-extension/
47 extension.toml
48 Cargo.toml
49 src/
50 lib.rs
51 languages/
52 my-language/
53 config.toml
54 highlights.scm
55 themes/
56 my-theme.json
57```
58
59## WebAssembly
60
61Procedural parts of extensions are written in Rust and compiled to WebAssembly. To develop an extension that includes custom code, include a `Cargo.toml` like this:
62
63```toml
64[package]
65name = "my-extension"
66version = "0.0.1"
67edition = "2021"
68
69[lib]
70crate-type = ["cdylib"]
71
72[dependencies]
73zed_extension_api = "0.1.0"
74```
75
76Use the latest version of the [`zed_extension_api`](https://crates.io/crates/zed_extension_api) available on crates.io. Make sure it's still [compatible with Zed versions](https://github.com/zed-industries/zed/blob/main/crates/extension_api#compatible-zed-versions) you want to support.
77
78In the `src/lib.rs` file in your Rust crate you will need to define a struct for your extension and implement the `Extension` trait, as well as use the `register_extension!` macro to register your extension:
79
80```rs
81use zed_extension_api as zed;
82
83struct MyExtension {
84 // ... state
85}
86
87impl zed::Extension for MyExtension {
88 // ...
89}
90
91zed::register_extension!(MyExtension);
92```
93
94> `stdout`/`stderr` is forwarded directly to the Zed process. In order to see `println!`/`dbg!` output from your extension, you can start Zed in your terminal with a `--foreground` flag.
95
96## Forking and cloning the repo
97
981. Fork the repo
99
100> Note: It is very helpful if you fork the `zed-industries/extensions` repo to a personal GitHub account instead of a GitHub organization, as this allows Zed staff to push any needed changes to your PR to expedite the publishing process.
101
1022. Clone the repo to your local machine
103
104```sh
105# Substitute the url of your fork here:
106# git clone https://github.com/zed-industries/extensions
107cd extensions
108git submodule init
109git submodule update
110```
111
112## Extension License Requirements
113
114As of October 1st, 2025, extension repositories must include a license.
115The following licenses are accepted:
116
117- [Apache 2.0](https://www.apache.org/licenses/LICENSE-2.0)
118- [BSD 2-Clause](https://opensource.org/license/bsd-2-clause)
119- [BSD 3-Clause](https://opensource.org/license/bsd-3-clause)
120- [GNU GPLv3](https://www.gnu.org/licenses/gpl-3.0.en.html)
121- [GNU LGPLv3](https://www.gnu.org/licenses/lgpl-3.0.en.html)
122- [MIT](https://opensource.org/license/mit)
123- [zlib](https://opensource.org/license/zlib)
124
125This allows us to distribute the resulting binary produced from your extension code to our users.
126Without a valid license, the pull request to add or update your extension in the following steps will fail CI.
127
128Your license file should be at the root of your extension repository. Any filename that has `LICENCE` or `LICENSE` as a prefix (case insensitive) will be inspected to ensure it matches one of the accepted licenses. See the [license validation source code](https://github.com/zed-industries/extensions/blob/main/src/lib/license.js).
129
130> This license requirement applies only to your extension code itself (the code that gets compiled into the extension binary).
131> It does not apply to any tools your extension may download or interact with, such as language servers or other external dependencies.
132> If your repository contains both extension code and other projects (like a language server), you are not required to relicense those other projects—only the extension code needs to be one of the aforementioned accepted licenses.
133
134## Publishing your extension
135
136To publish an extension, open a PR to [the `zed-industries/extensions` repo](https://github.com/zed-industries/extensions).
137
138In your PR, do the following:
139
1401. Add your extension as a Git submodule within the `extensions/` directory
141
142```sh
143git submodule add https://github.com/your-username/foobar-zed.git extensions/foobar
144git add extensions/foobar
145```
146
147> All extension submodules must use HTTPS URLs and not SSH URLS (`git@github.com`).
148
1492. Add a new entry to the top-level `extensions.toml` file containing your extension:
150
151```toml
152[my-extension]
153submodule = "extensions/my-extension"
154version = "0.0.1"
155```
156
157> If your extension is in a subdirectory within the submodule you can use the `path` field to point to where the extension resides.
158
1593. Run `pnpm sort-extensions` to ensure `extensions.toml` and `.gitmodules` are sorted
160
161Once your PR is merged, the extension will be packaged and published to the Zed extension registry.
162
163> Extension IDs and names should not contain `zed` or `Zed`, since they are all Zed extensions.
164
165## Updating an extension
166
167To update an extension, open a PR to [the `zed-industries/extensions` repo](https://github.com/zed-industries/extensions).
168
169In your PR do the following:
170
1711. Update the extension's submodule to the commit of the new version. For this, you can run
172
173```sh
174# From the root of the repository:
175git submodule update --remote extensions/your-extension-name
176```
177
178to update your extension to the latest commit available in your remote repository.
179
1802. Update the `version` field for the extension in `extensions.toml`
181 - Make sure the `version` matches the one set in `extension.toml` at the particular commit.
182
183If you'd like to automate this process, there is a [community GitHub Action](https://github.com/huacnlee/zed-extension-action) you can use.
184
185> **Note:** If your extension repository has a different license, you'll need to update it to be one of the [accepted extension licenses](#extension-license-requirements) before publishing your update.