I need this to be able to reroute work-related email to my work inbox.

Essential for building a good mail workflow

This sieve feature is essential for email workflow.
I like to forward purchase invoices to our accounting system automatically.

This is essential for shared accounts that require email verification codes.

+1 def need a redirect

Also opened a github issue on it if you like to comment / up it there:

https://github.com/ProtonMail/libsieve-php/issues/38

I also need the Sieve redirect to be able to organize and delegate incoming e-mails ... plz prioritize this!

Without this, I can't delegate emails to my assistant.

I just want to redirect newsletters to another service. Please add this :)

Conditional forwarding would be very important. Even being able to generate and email based on a filter being satisfied would do as well.
Thanks

+1
Target Use Case: I'd like to forward informed delivery digests (physical mail summaries) to an external system for automated processing and notification. The post office does not allow me to specify a different email just for informed delivery notices.

+1 for `redirect`

Really miss this feature :-(

In our family situation I would like this feature to be able to create additional addresses (for our own domain name) for our kids and forward it to both parents. Adding a separate account for this would (a) be cosly and (b) would need us to check multiple inboxes. Forwarding would be much more user friendly and would help us a lot!

i think it is overlooked feature. Current sieve implementation allows mail rejections. I'd argue - redirect(forward) copy shouldn't be missing. all sive script are executed before inbox delivery. and considering that headers are not encrypted it should be straightforward.