expanding environment variables on Vercel

[joggienl]

Does anybody know if you can setup vervel environment variables to use other variables?

As an example of what I try to achieve, could I use the VERCEL_URL environment variable in a custom environment variable:

This does work locally in your .env.local file, but it does not seem to work on Vercel.

[joggienl]

The nextjs documentation has what I need but apparently this does not work on Vercel. Ideas are welcome 😅

Note: Next.js will automatically expand variables ($VAR) inside of your .env* files. This allows you to reference other secrets, like so:

# .env
HOSTNAME=localhost
PORT=8080
HOST=http://$HOSTNAME:$PORT

If you are trying to use a variable with a $ in the actual value, it needs to be escaped like so: \$.

For example:

# .env
A=abc

# becomes "preabc"
WRONG=pre$A

# becomes "pre$A"
CORRECT=pre\$A

Source: environment variable expansion

[joggienl]

Thanks @amyegan !

[T99]

@amyegan Any updates/timeline on when this might be fixed?

[iamarpitpatidar]

@amyegan any updates on the feature yet ?

[julietgar]

@amyegan any update with this? I'm interested on this feature. Thanks!

[Wazbat]

Any update on this?

[amyegan]

Hey 👋 The original solution is still valid, but I want to share an update with links to some related docs. Next.js, and some other frameworks, will automatically expand $ variables in your .env* files.

• Referencing Other Variables
• Environment Variable Load Order

There are likely many possible ways to reach the same goal. If the recommended strategy doesn't work for your particular app or workflow, you can try some of the other ideas shared in vercel/next.js#16429. If you find a different solution, let us know what worked best for you!