> ## Documentation Index
> Fetch the complete documentation index at: https://developer.upsun.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Tethered

> Sync your local Upsun with your remote environment to start contributing.


When you develop a project, a significant amount of work takes place
locally rather than on an active Upsun environment. You want to ensure
that the process of local development is as close as possible to a deployed
environment.

You can achieve this through various approaches. For example, you can use
Symfony Server with tethered data.

To do so, when testing changes locally, you can connect your locally running
Symfony Server to service containers on an active Upsun environment.

This methodology has several advantages:

* It avoids installing anything on your local machine but your stack runtime.
* It ensures that you are using the same versions of all services on your local
  machine and in production.

<Warning>
  <h4>Warning</h4>
  Never use this method on the **main** environment as changes made on your local
  machine will impact production data.
</Warning>

## 1. Start your local Server

Use the official path to start your local server locally.

## 2. Create the tethered connection

1. Create a new environment off of production:

   ```bash theme={null}
   upsun branch new-feature main
   ```

2. Open an SSH tunnel to the new environment's services:

   ```bash theme={null}
   upsun tunnel:open
   ```

   This command returns the addresses for SSH tunnels to all of your services that you can then use within your local source code:

   ```bash theme={null}
   upsun tunnel:open
       SSH tunnel opened to rediscache at: redis://127.0.0.1:30000
       SSH tunnel opened to database at: pgsql://main:main@127.0.0.1:30001/main

       Logs are written to: /Users/acmeUser/.upsun/tunnels.log

       List tunnels with: upsun tunnels
       View tunnel details with: upsun tunnel:info
       Close tunnels with: upsun tunnel:close

       Save encoded tunnel details to the PLATFORM_RELATIONSHIPS variable using:
       export PLATFORM_RELATIONSHIPS="$(upsun tunnel:info --encode)"
   ```

3. When you've finished your work,
   close the tunnels to your services by running the following command:

   ```bash theme={null}
   upsun tunnel:close --all -y
   ```