I have added vite.config.mjs into my theme directory and when building theme on hubspot aliases work fine.
But when starting `hs-cms-dev-server .` I get "Error when evaluating SSR module /{path_to_module}: failed to import “@/ui/bla-bla”.
Also, it would be wonderfull if there is some documentation for
@hubspot/cms-dev-server package. I have seen a post from 2023 saying that it is in private beta. Maybe now it is time? 
Hi @notyourhero and welcome, we are so glad you are here! 
Thanks for asking the HubSpot Community!
For information, here are some resources that might be of interest:
- Local Development
- Getting started with local development
- Getting started with themes
- Themes overview
- HubSpot Developers
Also, you can access product updates and features in Beta in app, from your account. You find the product updates when clicking on your name account at the top right corner, then “Product Updates”.
Here is a post about it: “How to Stay Updated on HubSpot’s Latest Product Changes”.
I’d love to put you in touch with our Top Experts: Hi @sylvain_tirreau, @Anton and @zach_threadint do you have suggestions to help @notyourhero, please?
Have a lovely day and thanks so much in advance for your valuable contributions! 
Bérangère
This is likely due to Node not supporting @/ alias resolution.
But this is typically an issue that should be escalated to the development team. Maybe by using this form: HubSpot Developer Feedback Form (@BérangèreL will be able to confirm or not that this is where you should address your problem).
Otherwise, you have this documentation (Local development - HubSpot docs), very fragmentary and incomplete, that’s true.
As far as a debugged my way through @hubspot/cms-dev-server code, it something to do with vite resolving modules in ssr, but vite docs says that resolve.alias will work in ssr context, so maybe its the problem of cms-dev-server itself
Did you ever find a solution for this issue? I’m running into the exact same situation where upgrading to a newer version of @hubspot/cms-dev-server code now doesn’t serve me components. I have to revert to at least 1.0.6 in order to my local environment up and running.
It looks like the package is merging both our local vite config and it’s own to create the proxy environment and is omitting alias in that process.
I believe this essential package for running projects locally needs to be updated to support the ability to pass through the entire vite config file.
Hey @codal-jamie - thanks for posting in the Community!
I’d like to tag in the contributors from this original thread to see what may have worked in solving for the issue! @notyourhero and @sylvain_tirreau - any insight on what @codal-jamie may be able to try for the above inquiry?
Shane, Senior Community Moderator