> For the complete documentation index, see [llms.txt](https://docs.cymbal.co/help/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cymbal.co/help/setting-up-cymbal/email-setup/custom-email-warmup.md).

# Custom Email Warmup

Every new email address must go through a warmup process in order to ensure that it has a good sending reputation. This is how the process works:

1. After connecting your custom email, Cymbal will only send a subset of emails through the new domain. The rest of the emails will be sent through one of Cymbal's domains ( ex`cymbal.co`).
2. As you continue to send out email campaigns, Cymbal will send more and more traffic through your email address.
3. This process can take 2-6 weeks depending on the size of your email list and the amount of emails that you send.