zulip/docs/prod-requirements.md

# Requirements

Note that if you just want to play around with Zulip and see what it looks
like, it is easier to install it in a development environment
following [these
instructions](readme-symlink.html#installing-the-zulip-development-environment),
since then you don't need to worry about setting up SSL certificates and an
authentication mechanism. Or, you can check out the
[developers' chatroom](http://chat.zulip.org/) (a public, running Zulip
instance).

## Server

#### 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 strong 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).

* Disk space: You'll need at least 10GB of free disk space. If you intend to
  store uploaded files locally rather than on S3 you will likely need more.

#### 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][email-mirror-code] you may also
  need incoming port 25 open.

[email-mirror-code]: https://github.com/zulip/zulip/blob/master/zerver/management/commands/email_mirror.py

* Outgoing HTTP(S) access (ports 80 and 443) to the public Internet so
  that Zulip can properly manage inline image previews.  If you want
  to be able to send email from Zulip, you'll also need outgoing SMTP
  access to your mail server (using port 587).

#### Operating System

Ubuntu 14.04 Trusty and Ubuntu 16.04 Xenial are supported for running
Zulip in production. 64-bit is recommended.

#### Domain name

You should already have a domain name available for your Zulip
production instance. In order to generate valid SSL certificates with Let's
Encrypt, and to enable other services such as Google Authentication, you'll
need to update the domains A record to point to your production server.

## Credentials needed

#### SSL Certificate

* SSL Certificate for the host you're putting this on (e.g. zulip.example.com).
  The installation instructions contain documentation for how to get an SSL
  certificate for free using [LetsEncrypt](https://letsencrypt.org/).

#### Outgoing email

* Email credentials Zulip can use to send outgoing emails to users
  (e.g. email address confirmation emails during the signup process,
  missed message notifications, password reminders if you're not using
  SSO, etc.).

Once you have met these requirements, see [full instructions for installing
Zulip in production](prod-install.html).