Migrating to Slice Machine

I have a project that was created mostly without slices and as I understand it, even the slices I have are not the same format as the ones that work with Slice Machine.

Is there a guide for migrating to Slice Machine from the older format?
Is it possible to do this gradually?

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Hello @seanl. Thanks for reaching out.
There is no official procedure or guide to migrate from the legacy builder to Slice Machine. We will give you a public announcement if this changes in the future.


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Hi Pau and Prismic Team

It has been 5 months since the last post in this thread. I run a design agencies's website as inhouse developer and would like to migrate from the legacy builder to slice machine. The reason i want to migrate is A. because the prismic documentation is all based on slice machine and B. because i love the shared slices aspect and that slices and custom types can be managed in the code.

Can you make a statement/estimate when a migration guide from legacy to slice machine will be published?

If i would know when there will be progress in the migration topic i could much better plan, how we will develop our website further this year. It makes a difference for our strategy/priorities if we go with legacy for another year or if we migrate to slice machine soon.

It would be really great to have a migration guide / info page which transparently informs what's possible already now and what is not possible yet. Currently the info seems to be scattered in the forum.

Thanks a lot : )

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Hello @yaay, thanks for sharing your comments.

We currently don't have a single answer since each use case differs. For example, some projects were created at the beginning of Slice Machine. At this early stage, a repository could have both Builders. This is no longer possible. You can have Slice Machine or The Legacy Builder, but not both. Then some projects only use the Legacy Builder and want to switch. This last option isn't possible without having content loss because there can be conflicts with the Slices' structure, etc.

For this reason, we advise all our users to start using Slice Machine from the beginning of their project.

We're constantly working on improving the experience of all users. However, we don't have an update for when a guide or tool for migration could be released. We understand the inconvenience this may cause.

Hi, I'm in a similar boat: old project (2018) with a lot of content that needs to be reworked - transition from React to Next.js - and wondering what to do.
Is it safe to keep developing older projects using the Legacy Builder? It won't ever be completely deprecated will it?

That's correct, @zvitez; we will not replace the Legacy Builder with Slice Machine. So you can continue using your past repositories without a problem.

Our current focus is aimed at supporting everything related to Slice Machine, the plugins to connect them with the most used frameworks, and all the functionality of the Builder in general. This means that anything related to the Legacy Builder will not have updates or new features from now on. We recommend that all our users use Slice Machine in their new projects.

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If Prismic is going all in on Slice Machine and if the Legacy builder is not going to receive any updates in the future, shouldn't it be a top priority to create a "single button migration tool" from legacy builder to slice machine?

80% of the Prismic websites I'm working with are using the Legacy builder and they will stay that indefinitely, because they don't want to spend a large sum of money to just migrate to Slice Machine (which is a tool for developers, so it's a very hard sell to the decision makers).

The functionality of the Legacy Builder will remain stable. Therefore, projects that already exist should not worry about performing a migration. We still don't have an official tool or guide to migrate a project from Legacy Builder to Slice Machine.

Thanks for the confirmation. Slice Machine is an amazing tool and I'm happy to hear you're focusing on it.

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