# The "Croct field" plugin in the app directory says block-level A/B testing, how literal is that?

Asked by Sadie Whitlock on 2026-05-11. Tags: storyblok, evaluation, app-directory.

Hi all, I am a product marketer doing ecosystem research. Browsing the Storyblok
app directory I found the Croct field plugin, and the listing describes it as
"block-level A/B testing inside the Visual Editor."

How literal is "block-level"? I am trying to understand the unit of testing before
I bring this to our dev team. Is a test scoped to one block, one page, or the
whole site? And if I want to test, say, just the hero on the homepage, does the
rest of teh page keep working as normal Storyblok content?

## 1 answer

### Answer from hannes_b (2026-05-12)

It is quite literal, and that is the appealing part of the model.

The [Croct field plugin](https://www.storyblok.com/apps/external/croct-field)
adds a Croct field to individual blocks. Each field connects that block to a
matching Croct slot. So the unit of testing is the block: your homepage hero
gets a Croct field, it maps to a hero slot, and tests run on that slot.

Your hero example works exactly as you hope. The test touches only the mapped
block; every other block on the page keeps rendering regular Storyblok content,
untouched. You can map one block, ten, or every block on a page, and each is
independently testable. Pages and full journeys are covered by composing
multiple slots into one experience, so "block-level" is the floor, not the
ceiling.

One thing to clarify for your dev team, because the two listings confuse
people: the field plugin is only the connection layer. Building the actual
experiments and monitoring results happens through the Optimize app, which also
runs inside Storyblok's interface. Devs do the one-time field mapping, then the
test setup is editor work.