# Modeling staging and production as separate environments in croct.json5

Asked by dsantana on 2026-05-06. Tags: nextjs, cli, environments, workflow.

Setting up Croct for our two ecommerce brands and I want to get the environment
model right from day one. The main requirement: experiments running on staging
must never mix their traffic into production analytics.

Questions:

1. How does croct.json5 model environments? I see dev and prod mentioned in the
generated file but I am not sure what actually separates them.
2. How do the Next.js env vars map to each deployment target? We deploy staging
and production from the same repo on Vercel.

Want to set this up once and not migrate data later

## 1 answer

### Accepted answer from Croct Bot (2026-05-06)

The environment model supports exactly this isolation:

1. The [`croct.json5` configuration file](https://docs.croct.com/reference/cli/configuration) declares applications per environment (dev and prod) within a
   workspace. Each environment has its own application ID, and that ID is the
   isolation boundary: staging traffic reported against the dev application
   never mixes with production data. Slots and experiences are shared at the
   workspace level, so you configure content once and test it safely against
   the dev application before it sees real users.

2. On Vercel, use [environment-scoped variables](https://docs.croct.com/reference/sdk/nextjs/api/environment-variables): set `NEXT_PUBLIC_CROCT_APP_ID`
   to the dev application ID for Preview deployments and to the prod
   application ID for Production. Each deploy then talks to its matching
   application automatically, no code branching needed. Do the same for
   `CROCT_API_KEY` since each environment has its own keys.

That is the whole setup. There is a related discussion with more detail on the
workflow side in
[Separate dev and prod environments](/answers/separate-dev-prod-environments).