Side by side
Cerb vs MailStack
Both stand on shared inbox software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan Open source APILinuxSelf-hosted+1
Choose Cerb if your support team needs shared inbox workflows with SLA management, automation, and customer-facing help tools. Compare the plan billing and slot allowances to find a fit, especially if choosing Cerb Cloud, which bills per seat and per slot.
Visit Cerb
Free plan Self-hostedWeb
MailStack offers a focused receive-only shared inbox for teams that want to host and administer their own mail setup. Its single-node deployment requirements and lack of standard outbound and mailbox protocols are important constraints to weigh.
Visit MailStackThe facts
| Cerb | MailStack | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Yes | Not published |
| Runs on | API, Linux, Self-hosted, Web | Self-hosted, Web |
| Lowest paid plan | Cerb Cloud: $40 per seat a month | Free or on request |
| Plans published | 5 | 1 |
| Maker | Cerb | Not published |
| Website | cerb.ai | vib.tools |
| On shared inbox software | #1 of 30 | #5 of 30 |
Cerb: what it does well
- Shared inbox with SLA management.
- Includes help center and customer portal capabilities.
- Ticket automation and API access are available.
- Community plan has unlimited workers and seats.
- Self-hosted and cloud paid plans are offered.
What to know first
- Cerb Cloud pricing adds a per-slot charge to per-seat billing.
- Community includes three concurrency slots.
- Community includes two AI agent turns per slot.
MailStack: what it does well
- Open-source and free under GNU AGPL version 3.0 or later
- Shared mailboxes have object-level isolation
- Includes attachment protection and authorized downloads
- Lists backup, restore, rollback, and verification tools
What to know first
- Reference deployment is single-node only
- No public SMTP submission, IMAP, or POP3
- Requires Ubuntu Server 24.04 LTS, public DNS, and inbound ports
- Excludes public registration and outbound campaigns
Alternatives to Cerb Alternatives to MailStack The whole list