What is the division of labor between the Croct field plugin and the Optimize app?
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
They cover two different layers of the integration, and yes, you use both.
The Croct field plugin 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 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 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 if you hit installation issues.