Requirements

To run a Zulip server, you will need:

  • A dedicated machine or VM
  • A supported OS:
    • Ubuntu 18.04 Bionic
    • Ubuntu 16.04 Xenial
    • Ubuntu 14.04 Trusty (not recommended for new installations)
    • Debian 9 Stretch
  • At least 2GB RAM, and 10GB disk space
    • If you expect 100+ users: 4GB RAM, and 2 CPUs
  • A hostname in DNS
  • Credentials for sending email

For details on each of these requirements, see below.

Server

General

The installer expects Zulip to be the only thing running on the system; it will install system packages with apt (like nginx, postgresql, and redis) and configure them for its own use. We strongly recommend using either a fresh machine instance in a cloud provider, a fresh VM, or a dedicated machine. If you decide to disregard our advice and use a server that hosts other services, we can’t support you, but we do have some notes on issues you’ll encounter.

Operating System

Ubuntu 18.04 Bionic, Ubuntu 16.04 Xenial, Ubuntu 14.04 Trusty and Debian Stretch are supported for running Zulip in production. 64-bit is recommended. We also recommend installing on the newest option you’re comfortable with, to save your organization the work of upgrading.

If you’re using Ubuntu, the Ubuntu universe repository must be enabled, which is usually just sudo add-apt-repository universe.

Hardware Specifications

  • CPU and Memory: For installations with 100+ users you’ll need a minimum of 2 CPUs and 4GB RAM. For installations with fewer users, 1 CPU and 2GB RAM is sufficient. We strongly recommend against installing with less than 2GB of RAM, as you will likely experience out of memory issues installing dependencies. We recommend against using highly CPU-limited servers like the AWS t2 style instances for organizations with a hundreds of users (active or no).

    See our documentation on scalability for advice on hardware requirements for larger organizations.

  • Disk space: You’ll need at least 10GB of free disk space for a server with dozens of users. If you intend to store uploaded files locally rather than on S3 you will likely need more, depending how often your users upload large files. You’ll eventually need 100GB or more if you have thousands of active users or millions of total messages sent.

Network and Security Specifications

  • Incoming HTTPS access (usually port 443, though this is configurable) from the networks where your users are (usually, the public Internet). If you also open port 80, Zulip will redirect users to HTTPS rather than not working when users type e.g. http://zulip.example.com in their browser. If you are using Zulip’s incoming email integration you may also need incoming port 25 open.
  • Outgoing HTTP(S) access (ports 80 and 443) to the public Internet so that Zulip can properly manage inline image previews. You’ll also need outgoing SMTP access to your SMTP server (the standard port for this is 587) so that Zulip can send email.

Domain name

You should already have a domain name (e.g., zulip.example.com) available for your Zulip server. In order to generate valid SSL certificates with Certbot, and to enable other services such as Google authentication, you’ll need to set the domain’s A record to point to your production server.

Credentials needed

SSL Certificate

Your Zulip server will need an SSL certificate for the domain name it uses. For most Zulip servers, the recommended (and simplest) way to get this is to just use the --certbot option in the Zulip installer, which will automatically get a certificate for you and keep it renewed.

For test installations, an even simpler alternative is always available: the --self-signed-cert option in the installer.

If you’d rather acquire an SSL certificate another way, see our SSL certificate documentation.

Outgoing email

  • Outgoing email (SMTP) credentials that Zulip can use to send outgoing emails to users (e.g. email address confirmation emails during the signup process, missed message notifications, password reset, etc.). If you don’t have an existing outgoing SMTP solution, read about free outgoing SMTP options and options for prototyping.

Once you have met these requirements, see full instructions for installing Zulip in production.