Larksuite as Email provider with Custom Domain, and Adding Catch-All for Larksuite with MXGuardDog

Larksuite as Email provider with Custom Domain

Larksuite is international version of FeiShu, a Slack alternative by ByteDance.

Some benefits of Lark:

  • Free for 50 accounts
  • Free collaboration software
  • Free audio transcription with Lark Minutes
  • 200GB shared Email storage
  • 100GB shared storage, single file less than 250MB
  • Unlimited custom Email domain!
  • Email migration tool available
  • Supports IMAP IDLE for JIT push

But not without limitations:

  • ByteDance is a Chinese company that owns TikTok - bad track record for privacy and security
  • No native catch-all Email <-- fixing in this post
  • Mandatory App Password for IMAP, can be only generated from within client rather than web

Plus some gotchas:

  • IMAP(aka Third Party Email Client) disabled by default - has to be enabled by admin
  • DKIM disabled by default
  • Auto Forwarding disabled by default

Adding Catch-All for Larksuite with MXGuardDog

MXGuardDog is an external anti-spam service that replaces your MX server who conducts filtering and only lets filtered emails pass through with a catch-all functionality, making it possible to add catch-all to Larksuite. Although MXGuardDog is not free, you can generate enough credits from their affiliate program webpage to cover the cost.

This guide assumes you have:

  • Successfully added your domain to Larksuite and it shows a "Enabled" state
  • Control over your DNS records


  1. Register an account with MXGuardDog using your email address and domain.
  2. Adjust the UI language at, time zone at, and aggression level at
  3. Add all named email addresses at Each named address costs 1 credit per month. Enable catch-all and set up the target mailbox - unnamed addresses will NOT consume any credits.
  4. Add Larksuite's MX servers at and Send a test email to verify connectivity.
  5. Set the MX records according to Refresh the page to verify.
  6. Create some web pages for and include links. Note they can be from DIFFERENT domains. One link on a partner site's root domain can earn 30 credits per month for 30 named addresses.
  7. Send some test emails to random mailboxes on your domain from other providers. You should see them appear in Lark with [catch-all] in the title. Adjust any auto rules as needed, like moving messages to a specific folder.

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