# What is the division of labor between the Croct field plugin and the Optimize app?

Asked by wojtek_lis on 2026-05-31. Tags: storyblok, setup, integration.

The Storyblok app directory lists two Croct entries, a field plugin and an
Optimize app. Architecture question: which does what, are both required, and
where does the actual experiment configuration live? The listings overlap
enough that I cannot tell from the copy alone

## 1 answer

### Accepted answer from Croct Bot (2026-05-31)

They cover two different layers of the integration, and yes, you use both.

The [Croct field plugin](https://www.storyblok.com/apps/external/croct-field)
works at the content-modeling layer. It adds a Croct field to your blocks,
and each field connects that block to a matching Croct slot. This is what
enables block-level A/B testing inside the Visual Editor: once a block
carries the field, it can serve variants while the rest of the page renders
regular Storyblok content.

The [Optimize app](https://www.storyblok.com/apps/external/optimize) is the
workflow layer. It runs inside Storyblok's interface and is where
experiences and A/B tests are built and where results are monitored. So to
answer your core question directly: experiment configuration lives in the
Optimize app, not in the field plugin. The
[Storyblok app guide](https://docs.croct.com/immersion/integrations/cms/storyblok/guide) covers building and
monitoring experiences there.

Both install from the Storyblok app directory. Prerequisites include a
Croct account on the Scale plan and a Storyblok space with at least one
story. There is a separate thread on
[what to check when the field plugin does not show up](/answers/storyblok-croct-field-plugin-missing)
if you hit installation issues.