System Requirements

Below you can find the (minimum) system requirements for the collaboration server as well as for all optional modules.

Supported Browsers

Note: If you intend to run video see Browser Requirements to run Video.

unblu is optimized to run on modern browsers. We do not support browsers older than the following:


  • Internet Explorer 10 (or newer)
  • Google Chrome 40 (or newer)
  • Apple Safari 7 (or newer)
  • Mozilla Firefox 30 (or newer)


  • Safari on iOS 8 (or newer)
  • Chrome on Android 4.2+

Usability restrictions apply for small screens.

Collaboration Server

Hardware Requirements

A single server setup (optionally with a hot standby) is the most robust, lowest cost to maintain, solution required to run a co-browsing infrastructure. To accommodate 10-20 concurrent co-browsing sessions (this means active usage of co-browsing in parallel), the following minimum requirements apply:

  • 1 Recent CPU core running at 2.4GHz
  • 4 GB RAM
  • 10 GB hard drive

Any additional 10-20 concurrent sessions require 1 additional core, 4 additional GB of RAM, and 4 additional Mbit of bandwidth.

With the outlined specs below, it is possible to scale up to 250 concurrent sessions.

  • Recent 16 core CPU with 2.4GHz or better
  • 64 GB RAM
  • SSD (min 100 GB available space on top of OS)
  • Gigabit Ethernet or fiber channel network

Memory Handling

It is not possible to predict exact memory usage, given traffic, concurrent use, page complexity, etc. However, server class JVMs use an initial 1/64 of physical memory with a maximum of 1/4 of physical memory. JVMs can use up to 32GB if there is 128GB of physical memory available. In the first example (above) 1GB will be automatically used for JVM 8. In the second example 16GB will be available.

If you want to fine-tune the heap size for the JVM see the following Oracle document:

Java Command Non-Standard Options

You can find further information on server class JVMs here:

Garbage Collector, Heap, and Runtime Compiler Default Selections

Client JVM Default Initial and Maximum Heap Sizes

We recommend you start with 4GB RAM and use the -Xmx (maximum allowed size) setting for fine-tuning.

The Collaboration Server is built to be deployed to any Servlet Container that supports Servlet API Version 2.5 or higher running on Java 8.

Note: unblu 4.3 will only run with Java 8. (Any version of Java below, or above, Java 8 will not run.)

Network Requirements

The collaboration server needs to be accessible via HTTP(S) visitor(s) and agent(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

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

Rendering Service (universal and document co-browsing)

Document co-browsing and universal co-browsing, require the rendering service to be installed in addition. The rendering service is based on Docker. It requires a separate host to run docker with the rendering service docker image available at

Note: From version 4.2 onwards, the collaboration server requires the Docker rendering service tags to be version-specific to the collaboration server version used. So, if you use unblu 4.2 then 4.2 is the tag version number of the unblu Docker rendering service you must use. unblu 4.3 will use 4.3, and so on.

Rendering Service Hardware Requirements

Resource consumption is entirely dependent on the size of the documents loaded, dynamic elements of websites visited.

Recommended starting configuration:

  • Recent 16 core CPU with 2.4GHz or better
  • 32 GB RAM
  • Gigabit Ethernet or fiber channel Network
  • SSD with 100 GB

Supports approximately 30 concurrent rendering sessions.

The rendering service is delivered as a docker image and requires a docker environment to be deployed on.

The unblu Collaboration Server must be able to communicate with the rendering service via SSH protocol.

The rendering service must be able to communicate with the Collaboration Server using the HTTP(S) protocol.

Note: Either no proxy must be between these two servers, or the proxy must be transparent.

Video Chat

The video chat feature is built on the tokbox cloud service.

This may seem like a problem for financial institutions who prefer everything to sit behind their own firewalls. However, using the tokbox cloud service is no different, in principle, from making a telephone call through a provider.

Browser Requirements to run Video

Running the audio / video service requires WebRTC support which is provided by the following Browsers:

Windows OS

  • Google Chrome (56+)
  • Firefox (44+)
  • Internet Explorer (11+) with the Opentok Plugin for Internet Explorer provided at the start of an audio / video chat.
  • Microsoft Edge (15+)


  • Google Chrome (56+)
  • Firefox (44+)
  • Safari (11+)


  • iOS (11.2+)
  • Android WebView Chromium (67+) not dependent on Android version but must be kept up-to-date with Google Play store.

Network Requirements for Video

Note: Both the visitor page and the Agent desk must be hosted via HTTPS.

Running the audio / video service requires the Browser to access the audio / video chat services on the internet over specific ports in order to work.

The audio / video chat service uses the following domains:

  • *
  • *

The following HTTPS verification servers must be accessible for SSL certificate verification:



The minimal Requirement is that TCP port 443 is open. Some firewall/proxy rules only allow for SSL traffic over port 443. You will need to make sure that non-web traffic can also pass over this port.

Better Experience:

In addition to the minimal requirements being met, we also recommend that UDP port 3478 is open. The User Datagram Protocol (UDP) favours low latency over error-correction and is well-suited to audio and video communications.

Port 3478 only accepts inbound traffic after an outbound request is sent. The connection is bidirectional but is always initiated from the corporate network/client so it is not possible for an external entity to send malicious traffic in the opposite direction.

Best Experience:

For the best possible experience, we recommend that UDP ports 1025 - 65535 be open.

You can test if a network meets the connectivity requirements by using the OpenTok Connectivity Doctor: (you must use Chrome). There is also a Connectivity Doctor app in the Apple App Store as well as the Google Play Store.

Bandwidth Requirements

  • Video: 300 kbps per stream (recommended lowest level)
  • Audio: 50 kbps per stream (recommended lowest level)

Server Communication with Opentok

The Collaboration Server must be able to communicate with which is a service located on the Internet. Thus, port 443 must be open for outbound traffic to

Database Server Hardware Requirements

These (hardware) recommendations should be regarded as a starting point. We cannot know how your system may evolve and therefore cannot define exact specifications for your particular needs. Your hardware requirements will be a direct function of the types and volume of data stored.

  • Recent Quad-core Architecture

  • 16 GB Ram

  • 200 GB disk (SSD) - most disk space will be used to support IO

The above hardware specification should produce the following performance

  • 50,000 sessions per week

  • (equals) 200 sessions per agent per week for 250 agents

Mobile SDK Requirements

The mobile SDK supports the following platforms / versions.

Operating System Supported Version SDK Type
iOS 9.3.5 Framework
Android 4.2.x (API 17) Android Archive

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