Note: If you don't plan to make any code changes yourself, and only wish to run the latest prerelease versions of Zotero, you can just install a beta build.

Windows users: The following commands assume a POSIX-compliant system. To build Zotero on Windows, please follow the Windows-specific steps first.

1. Make sure you have Git and Git LFS installed. git lfs shouldn't show an error.
2. Clone the Zotero source code:

   git clone --recursive https://github.com/zotero/zotero zotero-client

3. Change to the source code repo:

   cd zotero-client

4. Check your system for the necessary tools and install any that are missing:

   app/scripts/check_requirements

   This script checks all requirements for the official Zotero distribution system. If you're only creating a custom build, you only need the build requirements listed at the top, not the distribution requirements.

5. Install Node.js modules using Node 18 or later:

   npm i

6. Build and run Zotero:

   app/scripts/build_and_run -r

The build will be placed in the app/staging/ folder in unpackaged form.

To build Zotero for another platform, first prepare Zotero's JavaScript source by running npm run build (or keep it prepared automatically as you make changes with npm start) and then run app/scripts/dir_build with the -p flag for the desired platform (e.g., app/scripts/dir_build -p w for Windows).

If running npm run build manually, you may need to set the environment variable NODE_OPTIONS=--openssl-legacy-provider to avoid an ERR_OSSL_EVP_UNSUPPORTED error.

After you've built the client, you can continue to run it from app/staging/ or move the app directory to a location of your choosing and start it normally.

For development, you'll generally want to leave the app in the staging directory and use the build_and_run helper script, but you can also call the launcher directly:

app/staging/Zotero.app/Contents/MacOS/zotero

app/staging/Zotero_linux-x86_64/zotero

app/staging/Zotero_win-x64/zotero.exe

In most cases, you'll want to use the helper script below instead of passing these flags directly to the launcher, but it's helpful to know the available options, which also work with release and beta builds:

• -ZoteroDebugText or -ZoteroDebug enable real-time debug output from Zotero.debug()
• -jsconsole will open the Error Console (Tools → Developer → Error Console)
• -jsdebugger starts the Firefox Browser Toolbox for debugging, if Zotero was built with devtools enabled; not available in release builds
• -ZoteroSkipBundledFiles skips style and translator initialization, which speeds up startup time after rebuilding if you're working on something that doesn't require styles or translators

For local development, you'll want to use the build_and_run helper script, which automates rebuilding Zotero and starting it with debug output enabled and the error console open. Create an alias for app/scripts/build_and_run with an appropriate name (e.g., zotero-source), or create a shell script in your path that selects a preexisting development profile and forwards command-line parameters:

#!/bin/bash -e
export ZOTERO_PROFILE="Dev"
~/zotero-client/app/scripts/build_and_run "$@"

You can then run, e.g., zotero-source -r to rebuild Zotero with your changes and start it up.

Options:

• -r Rebuild (calling `npm run build` automatically if `npm start` isn't running)
• -d Include Firefox Developer Tools in a rebuild and open the Browser Toolbox
• -b Skip bundled styles and translators — avoids extra work at startup if not needed

See Setting Up a Plugin Development Environment.

• In Keychain Access, create build keychain with password
• Import Developer ID certificate, public key, and private key
• Set up app-specific password for Apple developer account
• Create a config-custom.sh file in app/:

  SIGN=1
  KEYCHAIN=build
  KEYCHAIN_PASSWORD=<keychain password>
  NOTARIZATION_BUNDLE_ID=<bundle id (e.g., org.foo.App) — only used for notification emails>
  NOTARIZATION_USER="<username of Apple developer account>"
  NOTARIZATION_PASSWORD="<app-specific password for Apple developer account>"
  BUILD_PLATFORMS=m

• Verify that git is set to check out files without modifying line endings.

  $ git config --global core.autocrlf
  

  The response should be either empty (meaning false) or input. If set to true (as it may be if you selected the default option while installing the Windows version of git), change this with the following command:

  git config --global core.autocrlf false

  See the git manual for details on this setting.

• Install NSIS 3 and install the necessary plugins by running app/win/download-nsis-plugins.
• The Windows SDK is needed for the included signtool.exe utility. You can uncheck all other installation options. Adjust the path in app/config.sh to point to the correct version of the Windows SDK.

Note: These instructions are not applicable on macOS, which handles protocol handler and MIME type registration through the bundled Info.plist file. Additionally, they are only applicable on Windows if for some reason you want to run Zotero without running the installer.

Zotero should be registered as the system's default protocol handler for the zotero:// protocol.

Zotero should be registered as a handler for the following file extensions and MIME types:

Distribution steps are beyond the scope of this page, but see app/scripts/build_and_deploy for an example of the necessary steps.