Installing on Heroku


Recent changes by Heroku have altered how Tabbycat can be deployed on their service.

Heroku Deployments Overview

Tabbycat can be deployed to Heroku in two ways:

  1. A fork-based method, that approximates a ‘1-click’ install experience. Requires no technical background.

  2. A script-based method, which requires running a python script on your local machine. Requires some technical background.

Regardless of method, please note that Heroku no longer offers a free tier of hosting services. However, students with an academic email address now have access to $13 USD worth of credits (per month) to use on the service if they enrol in the GitHub Student Developer Pack. These credits will be sufficient to run 2-3 different tab sites simultaneously.

Please also note Heroku will require a debit/credit card to be attached to your account for verification purposes — even if you have free credits available. If using free credits, you should make note of the (annual) expiration of your GitHub student status and plan to either renew your status or cancel any Heroku services you don’t want to pay for.

Heroku Deployments using a Fork

GitHub Account Setup

  1. Create an account at GitHub. If you are a student, be sure to register with your academic email address.

  2. If you are a student: sign-up to claim the Student Pack so you will receive free Heroku credits. Note that it may take several days for the claim to process.

Heroku Account Setup

  1. Create an account at Heroku, or use an existing Heroku account.

  2. Once your GitHub student status has been confirmed, use the button here to claim your free monthly credits.

GitHub Fork and Deployment

In order to use a user-friendly ‘1-click deployment button’, you will need to make a ‘fork’ (personal copy) of Tabbycat on Github. To do so:

  1. Login to GitHub and go to the main Tabbycat project page

  2. Click the Fork button in the top-right

  3. On the next page, Uncheck the button that says Copy the develop branch only then click Create Fork

  4. The next page will show your copy of Tabbycat. Take note of your Github username and your fork’s name in the top-left, e.g. JaneSmith/tabbycat

  5. Open a new tab in your web browser and copy-paste in this URL without hitting enter (yet):
  1. In the URL address, replace YOUR_GITHUB_NAME with your GitHub username (e.g. JaneSmith) and replace YOUR_FORK_NAME with the name of your fork (e.g. tabbycat)

  2. Hit enter and fill out the details required. After the deployment process completes, you should have a new Tabbycat deployment

Heroku Deployments using the Deploy Script

We’ve tested these instructions successfully on Windows, Linux and macOS.

Requisite technical background

You will need to (briefly) work with a command-line interfaces to complete this method. When we say “command-line”, on Windows we mean Command Prompt, and on Linux and macOS we mean Terminal (or your favourite command shell).

If you haven’t used a command-line interface before, you may want to watch a very general and introductory tutorial. We will be providing the commands for you to enter, but you will need to know where to find the command-line and how to put text into it.

If you’re experienced with the command-line and Git, skip ahead to our TLDR list of commands.

Account Setup

Heroku is a platform as a service on which Tabbycat can be installed to be available on the internet. Naturally, this requires you to have a Heroku account. Head to the site and sign-up for one.


During the setup process, Heroku will ask you to verify your account by adding a credit card. A standard Tabbycat site may charge your card. If you have a paid Heroku Eco plan Tabbycat will use your Eco hours and you will not be charged, otherwise Tabbycat will use 2 Basic dynos which cost roughly $0.25/day or $7/month each.

1. Install dependencies

Install the Heroku Command Line Interface (CLI), then log in by running this in your command-line (and entering in your Heroku account details):

heroku login

If you don’t already have Git, follow the instructions on the GitHub website to set up Git.

2. Download Tabbycat with Git

Once git is installed, you can use it to download a copy of Tabbycat with these commands in your command-line:

git clone -b master

3. Run the Deploy Script

  1. Navigate on the command-line your Tabbycat directory. If you have not changed directories in the command-line since you cloned Tabbycat, this should just be:

    cd tabbycat
  2. Run the script to deploy the app to Heroku. Replace yourappname with your preferred URL. Your website will be at


On June 14th, 2023, Heroku started appending 12-character random suffixes to subdomains to prevent domain takeover when an app is renamed or deleted. Tabs created before this point will keep their domain, but new tabs will have the random suffix after yourappname.

python yourappname

The script uses the default dyno type for your Heroku account. If you have a paid Heroku Eco plan, the script will use Eco dynos. If you do not have an Eco plan, it will use Basic dynos which are billed based on usage. You can use the --web-dynos option to use a specific type, such as --web-dynos 1:basic if you have an Eco plan but wish to use Basic dynos.

This script has other options that you might find useful. Run python --help for details.

The script may work away on its own for 10-30 minutes before it asks you some questions to answer. When finished, it will open the app in your browser. It should look something like this:


That’s everything! You can then login with the account that you made by answering the script’s questions.

TLDR commands


We provide a “short version” for experienced users. Don’t just copy and paste these commands before you understand what they do! If things aren’t set up perfectly they can fail, so it’s important to supervise them the first time you do them. If this is all new to you, read the long version of the instructions below.

The script uses the default dyno type for your Heroku account. If you have a paid Heroku Eco plan, the script will use Eco dynos. If you do not have an Eco plan, it will use Basic dynos which are billed based on usage. You can use the --web-dynos option with the last command to use a specific type, such as --web-dynos 1:basic if you have an Eco plan but wish to use Basic dynos.

git clone
cd tabbycat
git checkout master
python yourappname

Heroku options you may want to change

If you have a large tournament, you may want to customize your Heroku app. This section provides some guidance on upgrades and settings you may wish to consider. Some of these configurations require you to have the Heroku Command Line Interface (CLI) installed.

Upgrading your database size

The Mini plan of Heroku Postgres, should work for most small tournaments. For large tournaments, however, you may find that you exceed the 10,000-row limit of this plan. It’s difficult to give general guidance on how many rows you’re likely to use, because it depends on which features of Tabbycat you use (e.g., if you use adjudicator feedback). But to give some idea:

  • Australs 2016, which had 74 teams, 8 preliminary rounds and heavily used adjudicator feedback, ended up at around 30,000 rows.

  • The Asia BP championships 2017 had 100 teams, 6 preliminary rounds, and mandatory feedback (i.e. 100% return rates) used 15,000 rows.

  • A 3 vs 3 tournament with 54 teams, 5 preliminary rounds, and which only lightly used adjudicator feedback ended up using around 4,500 rows

If you need more than 10,000 rows, you’ll need to upgrade to a larger Heroku Postgres Plan. The 10,000,000 rows allowed in the lowest paid plan, “Basic”, should certainly be more than sufficient.

If you’re not sure, you can always start at Mini—just be prepared to upgrade during the tournament if you run close to capacity.

Custom domain names

Your Heroku app will be available at You may want it to be a subdomain of your tournament’s website, like If so, you’ll need to configure your custom domain and SSL. Instructions for both are in the Heroku Dev Center:

The custom domain name basically requires two things: a DNS CNAME entry on your website targeting, and the custom domain configured on Heroku using heroku domains:add You’ll also need to provide an SSL certificate for your custom domain and add it using the heroku certs:add command.

If you’re using Tabbycat’s email notifications, you might also configure your email provider to use domain authentication—see Configuring an email provider.

Time zone

If you want to change the time zone you nominated during deployment, you can do so by going to the Heroku Dashboard, clicking on your app, going to the Settings tab, clicking Reveal Config Vars and changing the value of the TIME_ZONE variable. This value must be one of the names in the IANA tz database, e.g. Pacific/Auckland, America/Mexico_City, Asia/Kuala_Lumpur. You can find a list of these on Wikipedia in the ‘TZ*’ column.

Email provider

Changed in version 2.6: Tabbycat no longer automatically provisions SendGrid via Heroku.

Tabbycat does not come with an email provider. Before Tabbycat will send emails, you will need to install a third-party email provider yourself. To do so, you may add/change the following config vars:

  • DEFAULT_FROM_EMAIL: Email to send from

  • EMAIL_HOST: Host server

  • EMAIL_HOST_USER: Username for authentification to host

  • EMAIL_HOST_PASSWORD: Password with username

  • EMAIL_PORT (default 587): Port for server

  • EMAIL_USE_TLS (default True): Whether to use Transport Layer Security (True/False)

See Configuring an email provider for more information, including a few options for email service providers.

Upgrading an existing Heroku app


For most users, we recommend starting a new site for every tournament, when you set up the tab for that tournament. There’s generally not a pressing need to upgrade Tabbycat after a tournament is concluded, and every time you deploy a new site, you’ll be using the latest version at the time of deployment.

To upgrade an existing Heroku-based Tabbycat app to the latest version, you need to deploy the current version of Tabbycat to your Heroku app. There are several ways to do this. We list one below, primarily targeted at users with some background in Git.

The essence of it is that you need to create a Git remote for your Heroku app (if you don’t already have one), then push to it.


You should always back up your database before upgrading Tabbycat.

You’ll need both Git and the Heroku CLI, and you’ll need to be logged in to the Heroku CLI already.

  1. Take a backup of your database:

    $ heroku pg:backups:capture
  2. If you haven’t already, clone our Git repository and check out the master branch:

    $ git clone
    $ cd tabbycat
    $ git checkout master

If you’ve already cloned our Git repository, don’t forget to pull so you’re up to date:

$ git checkout master
$ git pull
  1. Check to see if you have a Git remote already in place:

    $ git remote -v
    heroku (fetch)
    heroku (push)

If you do, the name of the remote will be on the left (heroku in the above example), and the URL of your Git repository will be on the right. In the example above, our Tabbycat site URL would be; the Git remote URL is then

If a Git remote URL for your Tabbycat site doesn’t appear, then create one:

$ heroku git:remote --app yourappname --remote heroku
set git remote heroku to


If you tab many tournaments, it’ll probably be helpful to use a name other than heroku (say, yourappname), so that you can manage multiple tournaments.

  1. Push to Heroku:

    $ git push heroku master

This will take a while to complete.