Using system environment variables in Vercel to set preview URL for Sanity Studio.

has anyone hosting their studio on Vercel figured out a way to use its system environment variables ? i want to use the

VERCEL_URL

to set my studio's preview URL but can't find a way to add the

SANITY_STUDIO_

prefix. (i know this is more of a Vercel question, but my question there didn't get answered. hoping someone here has already figured this out!)

For one off env, perhaps you can do it with a npm prebuild script?

Could you use a plugin to insert a custom configuration option?

: please share how that goes! i’m considering a similar approach but using a Node script to make sure it works

cross-env

i got a reply from a Vercel maintainer , but neither suggested approach worked for me. (the first one just did nothing, & the second was irrelevant since it’s not a Next.js project.)

ok, i think i got something working! thanks , the prebuild approach seemed to do the trick. i tweaked it a bit, & did
& then that

prebuild.js

is the attached. so i’m actually making all the system variables available this way.(note that i’m on Node 14, & i had to add

"type": "module"

to my

package.json

. also, i had already added the

SANITY_ACTIVE_ENV

variable to each of my environments.)

i still feel like Vercel should support custom prefixes in the Environment Variables UI, but this should do the trick for now.

I attempted some tests on my own using sanity/node custom env values per https://www.sanity.io/docs/studio-environment-variables , hoping that vercel would have an easier time with those. I took a look at their suggestions, and didn’t have luck with that either. Hopefully this prebuild suggestion does the trick for you!