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System requirements — no cluster

This page outlines the minimum system requirements for the Unblu Collaboration Server, as well as for all optional modules, when run on a single server such as Apache Tomcat.

The no cluster setup does not fulfil the requirements of the Unblu secure messenger.
License requirements, supported browsers, video, database server, and mobile requirements are common to both cluster (Kubernetes/Openshift - YAML) and no cluster (WAR/EAR) installations.


While the server will run and the Agent Desk can be accessed, collaboration features won’t function until you have uploaded your license. See Licensing.

Supported browsers

Collaboration Server

Hardware requirements — single server — no cluster

A single server setup (optionally with a hot standby) is a low-cost (but limited) solution for running co-browsing infrastructure. To accommodate 10-20 concurrent co-browsing sessions, your hardware should fulfil the following minimum requirements:

  • 1 recent CPU core running at 2.4GHz

  • 4 GB RAM

  • 10 GB hard drive

  • Network capability providing at least 4 Mbit/s bandwidth

Each additional 10-20 concurrent sessions require 1 additional core, an additional 4 GB of RAM, and additional bandwidth of 4 MBit/s. For example, to run 250 concurrent co-browsing sessions would require hardware with the following specs:

  • A recent 16 core CPU with 2.4GHz or better

  • 64 GB RAM

  • An SSD with at least 100 GB space available on top of the operating system

  • Gigabit Ethernet or fiber channel network

The Collaboration Server is built to be deployed to any servlet container that supports servlet API Version 2.5 or higher running on Java 11.

  • Tomcat Version 7, 8, or 9.

    At present, Unblu is not compatible with Tomcat 10, which targets Jakarta EE rather than Java EE. Unblu is compatible with Jakarta EE 8; it is not compatible with Jakarta EE 9 or 9.1.

    We recommend that you deploy Unblu on Tomcat 9.

  • WebSphere 6.1 or higher

  • WebLogic 10.0 or higher

Memory handling

It is not possible to predict exact memory usage. We therefore recommend you start with 4 GB RAM and use the -Xmx option to fine-tune JVM memory usage.

If you want or need to fine-tune the heap size for the JVM, please consults the following Oracle documents:

Network requirements

The Collaboration Server needs to be accessible to visitors and agents via HTTP(S). In minimal configuration, the server does not communicate with other servers and does not require Internet access.

If additional modules are deployed see the following sections to find out which network connectivity requirements apply.

Minimal network bandwidth (10-20 concurrent sessions):

  • 4 Mbit/s

Any additional 10-20 concurrent sessions require 4 additional Mbit of bandwidth.

Network latency

You should take measures to keep network latency as low as possible.

  • For Unblu to work smoothly, a latency of under 200ms is recommended.

  • For the person controlling universal or document co-browsing, a latency of under 100ms is recommended.

If the network latency between Unblu and your users is greater than 500ms, features such as co-browsing or video calls become so slow that the user experience suffers significantly. With latency greater than 2000ms, the features are all but unusable.

Rendering Service

Universal co-browsing and document co-browsing require the Rendering Service. The Rendering Service is shipped as a Docker image, which is available at It requires a separate host to run Docker with the Rendering Service Docker image.

The Unblu Server must be able to communicate with the Docker socket using HTTP. It must also be able to communicate with the Rendering Service container via HTTP/2 on a port range specified on the Docker host.

If there is a proxy between these two servers, it must be transparent.

Rendering Service hardware requirements

Resource consumption depends heavily on the size of the documents loaded and the dynamic elements of websites visited.

Recommended starting configuration:

  • Recent 16 core CPU with 2.4GHz or better

  • 32 GB RAM

  • SSD with 100 GB

  • Gigabit Ethernet or fiber channel network

This setup supports approximately 10-30 concurrent rendering sessions. This figure depends on the website or document complexity and the maximum resolution of the video stream produced.

Video chat

Unblu supports several call service providers for audio and video call functionality. For more information, refer to Call service providers.

Database server hardware requirements