Skip to content


webKnossos Logo webKnossos is an open-source tool for annotating and exploring large 3D image datasets.

  • Fly through your data for fast skeletonization and proof-reading
  • Create 3D training data for automated segmentations efficiently
  • Scale data reconstruction projects with crowdsourcing workflows
  • Share datasets and annotations with collaborating scientists

Start using webKnossos - On your own server - User Documentation - Contact us





Boergens, Berning, Bocklisch, Bräunlein, Drawitsch, Frohnhofen, Herold, Otto, Rzepka, Werkmeister, Werner, Wiese, Wissler and Helmstaedter webKnossos: efficient online 3D data annotation for connectomics. Nature Methods (2017) DOI:10.1038/NMETH.4331.

Read more about the original publication.


webKnossos is open-source, so you can install it on your own server.

Check out the documentation for a tutorial on how to install webKnossos on your own server.

For installations on localhost, please see below.

Development installation


This is only recommended for local testing. Docker 17+ and Docker Compose 1.18+ are required.

git clone -b master --depth=1
cd webknossos
docker-compose pull webknossos

Open your local webknossos instance on localhost:9000 and complete the onboarding steps in the browser. Now, you are ready to use your local webKnossos instance.

See the wiki for instructions on updating this development setup.

For non-localhost deployments, check out the installation guide in the documentation.



If you are using OS X try using this awesome installer:

Or install Java manually and run:

# Install Homebrew package manager
/usr/bin/ruby -e "$(curl -fsSL"

# Install git, node.js, postgres, sbt, gfind, gsed
brew install git node postgresql sbt findutils coreutils gnu-sed redis
npm install -g yarn

# Start postgres
brew services start postgresql

# Create PostgreSQL user
psql -c "CREATE DATABASE webknossos;"
psql -c "CREATE USER postgres WITH ENCRYPTED PASSWORD 'postgres';"
psql -c "ALTER USER postgres WITH SUPERUSER;"
psql -c "GRANT ALL PRIVILEGES ON DATABASE webknossos TO postgres;"

# Checkout the webKnossos git repository
git clone

Ubuntu 20.04 LTS

sudo apt install -y curl ca-certificates wget
# Adding repositories for nodejs, sbt and yarn
curl -fsSL | sudo -E bash -
echo "deb all main" | sudo tee /etc/apt/sources.list.d/sbt.list
echo "deb /" | sudo tee /etc/apt/sources.list.d/sbt_old.list
curl -sL "" | sudo apt-key add
curl -sS | sudo apt-key add -
echo "deb stable main" | sudo tee /etc/apt/sources.list.d/yarn.list

sudo apt update
sudo apt install -y nodejs git postgresql postgresql-client scala sbt openjdk-8-jdk yarn redis-server build-essential

# Assign a password to PostgreSQL user
sudo -u postgres psql -c "ALTER USER postgres WITH ENCRYPTED PASSWORD 'postgres';"
# Clone the git repo to the current directory
git clone -b master --depth=1

If you already have a different Java version installed, set the default version to Java 8: - run sudo update-alternatives --config java - when prompted, select the desired version

On older Ubuntu distributions: Please make sure to have the correct versions of node, PostgreSQL and java installed.

Manual Installation

  • Install Java JDK 8 (from Oracle or OpenJDK)
  • make sure JAVA_HOME and JDK_HOME are set and PATH contains path to JDK


  • Install PostgreSQL from
  • PostgreSQL version 10+ is required
  • Install Redis from
node.js & yarn
  • Install node from
  • node version 12+ is required
  • Install yarn package manager: npm install -g yarn

Run locally

First, install all frontend dependencies via

yarn install
Note: During this installation step, it might happen that the module gl cannot be installed correctly. As this module is only used for testing webKnossos, you can safely ignore this error.

To start webKnossos, use

yarn start
This will fetch all Scala, Java and node dependencies and run the application on Port 9000. Make sure that the PostgreSQL and Redis services are running before you start the application.


For upgrades, please check the changelog & migration guide.


# Frontend linting
yarn run lint

# Format frontend code
yarn run pretty

# Format backend code
yarn pretty-backend

# Frontend type checking
yarn flow

# Frontend tests
yarn test-verbose

# End-to-end tests
docker-compose run e2e-tests

Contact and support

Ask for help in the community forum.

Contact us at

scalable minds offers commercial hosting, support and development services for webKnossos.


  • scalable minds -
  • Max Planck Institute for Brain Research –

webKnossos was inspired by KNOSSOS.


  • CircleCI for letting us run builds and tests on their CI
  • Browser Stack for letting us test WebKnossos on a variety of different devices Browserstack Logo



Back to top