[Fork mermaid](https://github.com/mermaid-js/mermaid/fork) to start contributing to the main project and its documentation, or [search for other repositories](https://github.com/orgs/mermaid-js/repositories).
Once you have cloned the repository onto your development machine, change into the `mermaid` project folder (the top level directory of the mermaid project repository)
```bash
cd mermaid
```
### Make `./run` executable
For development using Docker there is a self-documented `run` bash script, which provides convenient aliases for `docker compose` commands.
Ensure `./run` script is executable:
```bash
chmod +x run
```
```tip
To get detailed help simply type `./run` or `./run help`.
It also has short _Development quick start guide_ embedded.
```
### Install packages
```bash
./run pnpm install # Install packages
```
### Launch
```bash
./run dev
```
Now you are ready to make your changes! Edit whichever files in `src` as required.
Open <http://localhost:9000> in your browser, after starting the dev server.
There is a list of demos that can be used to see and test your changes.
If you need a specific diagram, you can duplicate the `example.html` file in `/demos/dev` and add your own mermaid code to your copy.
That will be served at <http://localhost:9000/dev/your-file-name.html>.
After making code changes, the dev server will rebuild the mermaid library. You will need to reload the browser page yourself to see the changes. (PRs for auto reload are welcome!)
## Verify Everything is Working
```bash
./run pnpm test
```
The `test` script and others are in the top-level `package.json` file.
All tests should run successfully without any errors or failures. (You might see _lint_ or _formatting_ warnings; those are ok during this step.)
## Last Words
Don't get daunted if it is hard in the beginning. We have a great community with only encouraging words. So, if you get stuck, ask for help and hints in the Slack forum. If you want to show off something good, show it off there.
[Join our Slack community if you want closer contact!](https://join.slack.com/t/mermaid-talk/shared_invite/enQtNzc4NDIyNzk4OTAyLWVhYjQxOTI2OTg4YmE1ZmJkY2Y4MTU3ODliYmIwOTY3NDJlYjA0YjIyZTdkMDMyZTUwOGI0NjEzYmEwODcwOTE)
![Image of superhero wishing you good luck](https://media.giphy.com/media/l49JHz7kJvl6MCj3G/giphy.gif)