Debug CSS optimization warnings
Learn how to troubleshoot CSS optimization warnings and identify whether they are caused by outdated components or a potential Framer bug.
CSS optimization warnings are rare in Framer. In most cases, they are caused by custom code components that rely on private Framer APIs. In some cases, they can also point to an issue in Framer itself.
About this warning
In August and September 2025, Framer introduced a new CSS optimizer. Some older component versions were not compatible with this optimizer, including older versions of components such as Vimeo and Code Block. Current Framer components are compatible with the new CSS optimizer.
For more background on custom code compatibility, see Custom Code.
What the warning looks like
You might see a warning like this:
How to debug the issue
Start by checking whether any components in your project have updates available. If updates are available, install them and then publish or preview your site again to confirm whether the warning is resolved.
If all components are already up to date and the warning still appears, contact our support team. This can help confirm whether the issue is caused by a project-specific component or an underlying bug in Framer. When you contact support, include the full warning message and note whether you have already updated all components in the project. This makes it easier to investigate the cause and speed up troubleshooting.
What should I do if I see a CSS optimization error in Framer?
If you see a CSS optimization error, check if there’s an update available for your components and update them. If all components are up-to-date and the issue still persists, reach out to Framer Support.
Which Framer components are affected by the new CSS optimizer?
The new CSS optimizer isn’t compatible with some older versions of certain components, such as Vimeo and Code Block from Framer. All current Framer components are compatible with the new CSS optimizer.
How can I resolve the 'Unexpected token Function("var")' error in Framer?
To resolve the 'Unexpected token Function("var")' error, update any affected components to their latest versions. If the problem continues after updating, contact Framer Support for further assistance.
Updated