How to run a CTFd instance

CTFd is a standard WSGI application so most if not all Flask documentation on deploying a Flask based application should apply. This page will focus on the recommended ways to deploy CTFd.

Server Requirements

At a minimum you should have a dual core CPU with at least 1 GB of RAM.

A generally recommended setup would have a quad core CPU with at least 2 GB of RAM.


CTFd provides automatically generated Docker images and one of the simplest means of deploying a CTFd instance is to use Docker Compose.

  1. Install Docker

  2. Install Docker Compose

  3. Clone the CTFd repository with git clone

  4. Modify the docker-compose.yml file from the repository to specify a SECRET_KEY environment for the CTFd service. :

      - UPLOAD_FOLDER=/var/uploads
      - LOG_FOLDER=/var/log/CTFd
      - DATABASE_URL=mysql+pymysql://root:ctfd@db/ctfd
      - REDIS_URL=redis://cache:6379
      - WORKERS=4
  1. Run docker-compose up
  2. You should now be able to access CTFd at http://localhost:8000

Standard WSGI Deployment

As a web application, CTFd has a few dependencies which require installation.

  1. WSGI server
  2. Database server
  3. Caching server

WSGI Server

While CTFd is a standard WSGI application and most WSGI servers (e.g. gunicorn, UWSGI, waitress) will likely suffice, CTFd is most commonly deployed with gunicorn. This is because of its simplicity and reasonable performance. It is installed by default and used by other deployment methods discussed on this page. By default it is configured to use gevent as a worker class.

Database Server

CTFd makes use of SQLAlchemy and as such supports a number of SQL databases. The recommended database type is MySQL. CTFd is tested with and has been installed against SQLite, Postgres, and MariaDB.

By default CTFd will create a SQLite database if no database server has been configured.

Caching Server

CTFd makes heavy use of caching servers to store configuration values, user sessions, and page content. It is important to deploy CTFd with a caching server. The preferred caching server option is Redis.

By default if no cache server is configured, CTFd will attempt to use the filesystem as a cache and store values in the .data folder. This type of caching is not very performant thus it is highly recommended that you configure a Redis server.


CTFd provides a basic Vagrantfile for use with Vagrant. To run using Vagrant run the following commands:

vagrant up

Visit http://localhost:8000 where CTFd will be running.

To access the internal gunicorn terminal session inside Vagrant run:

vagrant ssh
tmux attach ctfd

Debug Server

The absolute simplest way to deploy CTFd merely involves running python to start Flask’s built-in debugging server. This isn’t recommended for anything but debugging and should not be used for any kind of load. It is discussed here because the debugging server can make identifying bugs and misconfigurations easier. In addition, development mostly occurs using the debug server.


Server side settings and configuration

Last modified July 23, 2020: Fix other alerts (3e3ee79)