Very Slow Reload Times During Development in Cumulocity Web App

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Hi Cumulocity team,

I’m currently developing a custom web application on top of the Cumulocity platform using the standard devkit, and I’ve noticed that live reload during development is unusually slow ,often taking over 20 seconds, even for very minimal changes.

This delay happens even in a nearly blank project with no additional business logic or third-party libraries. I’ve tried some standard optimization steps, but the reload times remain long, which significantly slows down the development feedback loop.
With the newer angular projects, the inital reload time is under 1 second. As soon as I use @c8y/devkit the reload time goes to around 15-20 seconds which is not optimal for development.

What I’m hoping to understand:

  • Are these slow reload times expected in Cumulocity devkit projects?
  • Are there recommended best practices or configurations to improve development speed?
  • Is there any support for faster reload mechanisms like HMR or alternatives?

I’d really appreciate any guidance on how to make the development workflow faster and more efficient.

Thanks in advance!

Best regards,
Arif

2

Hey,

Let me try to answer your question:

  • Are these slow reload times expected in Cumulocity devkit projects?
    –> It depends on what you are running. Are you running an empty application or the cockpit/dm/admin app? If later, then yes, they are expected as for example, the Cockpit depends on many different modules that need to be compiled. It is not a good benchmark to compare a nearly empty starter project to a highly complex application. But I agree that it is not optimal. Perhaps we should examine other complex applications and their compilation speed to determine where we stand and what we can do.

  • Are there recommended best practices or configurations to improve development speed?
    → Yes, we recommend using plugin development. This allows for development in isolation and therefore not that much needs to be compiled. We have initial loading times of 8s.

  • Is there any support for faster reload mechanisms like HMR or alternatives?
    –> We had at a certain time support for –hmr flag. However, our experience is that it is not very useful. Mostly, only component styling can be replaced. Do you have good experience with it on other projects lately? Module federation has issues with hmr, but it might be worth investigating now and see if we can make it work.

Thanks
Jan