Patch demo

Patch Demo is a web site that lets you spin up short-lived MediaWiki instances for testing changes from Wikimedia's Gerrit code review. You can create wikis with unmerged, work-in-process changes.

Create temporary, public wikis to test:

MediaWiki core
Extensions and skins
Multiple patches together
Different MediaWiki versions
Wiki farms – Multiple wikis which share a CentralAuth (limited)

Public instance: https://patchdemo.wmcloud.org/

Quickstart

Requirements

Wikimedia global account
(optional) Get added to the Continuous_integration/Allow_list

Create a wiki

Demonstration of how to create a Patch Demo wiki with a patch from Wikimedia's Gerrit

Go to https://patchdemo.wmcloud.org/
Sign in to your Wikimedia global account

When prompted click "Allow" to let Patch Demo see your account info

Choose a MediaWiki version – Defaults to master
(Optional) Paste the URL to any Gerrit changes
Select an extension bundle or choose which extension to install – Defaults to Wikimedia
Click "Create demo"

Your wiki will be ready in a few minutes.

Use your wiki

After your wiki is ready, you'll be able to:

Link – each wiki is a public, sharable link where you can access your wiki (e.g., https://deadbeef.catalyst.wmcloud.org)
Edit – if you update your Gerrit patches, you can edit your wiki to use the latest. Change MediaWiki versions. Change extensions.
Delete – Once you're done testing, delete your wiki.

Tips

Delete when done: Click the Delete link in the wiki table on the Patch Demo homepage when you're finished testing. Wikis may be removed automatically if space is needed.
V+2 required: Patches must have Verified +2 review before you can create a Demo.
- This should happen automatically when your change passes its test if you're a member of Continuous_integration/Allow_list.
- Otherwise, ask another contributor to "recheck" your change.
Phabricator announcement: If you include a Bug: TXXX trailer in your Gerrit git commit message, PatchDemoBot will comment on Phabricator with a link to your wiki. Toggle the "Announce wiki on Phabricator" checkbox to disable.
Gerrit links: Gerrit will show a link on your change to your Patch Demo instance

Limitations

Not suitable for security-sensitive testing
MediaWiki only – no other services
Wiki farms support is basic – As of early 2026, each wiki in a wiki farm will share all enabled extensions, languages, and a subdomain (i.e., https://abcd1234.catalyst.wmcloud.org/wiki1 and https://abcd1234.catalyst.wmcloud.org/wiki2)
No dependency checking – While choosing an extension bundle should work fine, hand-selecting dependencies means wiki creation might fail if you're missing a dependency.

Report Issues or Request Features

File a task for the Phabricator project Catalyst (PatchDemo)

Add an Extension

See ADDING_EXTENSIONS.md for instructions on adding new extensions.

Project components/code

Patch Demo is a project that spans a handful of code repositories:

Component	Description
patchdemo	Web frontend (PHP)
catalyst-api	Backend API (Go)
catalyst-tofu	Cloud VPS Infrastructure management (OpenTofu)
ci-charts	Helm charts that make MediaWiki instances