Operating System Debian GNU/Linux 10 "Buster" - 64 bit (netinst) Important: The following requirements are general guidelines for getting started with XCALLY based on concurrent agents. Recommended minimum server sizes: Voice (Plus) Voice + Dialer (Dialer-gold) Omnichannel (Omni-gold) Full (Ultimate) Up to 30 agents** RAM: 2 GB CPU: 2 HDD: 32 GB RAM: 4 GB CPU: 4 HDD: 32 GB RAM: 4 GB CPU: 4 HDD: 32 GB RAM: 4 GB CPU: 4 HDD: 32 GB Up to 100 agents** RAM: 4 GB CPU: 4 HDD: 60 GB RAM: 6 GB CPU: 6 HDD: 60 GB RAM: 6 GB CPU: 6 HDD: 60 GB RAM: 6 GB CPU: 6 HDD: 60 GB 100 + agents** RAM: 4 GB CPU: 4 HDD: 100 GB RAM: 6 GB CPU: 6 HDD: 100 GB RAM: 6 GB CPU: 6 HDD: 100 GB RAM: 8 GB CPU: 8 HDD: 100 GB ** concurrent agents Remember to configure your system SWAP AREA properly (at least the double of the RAM) If you are planning to use complex IVR scripts (DB access and custom scripts) consider to double the RAM. If you need to store a lot of logs and call recordings, please evaluate a large HDD space. Calls recorded in wav format need about 1MB per minute, in GSM format about 300k per minute. CentOS default root partition is 50 GB, if you need more space set partition size manually during installation. For security reasons, please consider to install a proper firewall in front of your XCALLY server, especially if it is deployed on the Cloud. Amazon example Here you can find an example to properly deploy an Amazon AWS EC2 machine for XCALLY MOTION Licenses Please note that any change of any kind applied on your XCALLY server (i.e. CPU, memory, HDD, network etc…) can invalidate your XCALLY assigned license: for this reason any move and change of your XCALLY server must be carefully planned and notified to the XCALLY team. Scaling Recommended architecture if you need to scale over 50 agents: Recommended architecture if you need to scale over 200 agents: Please contact our XCALLY Team for help and more details about this scalable deployment solution. To use the Phonebar: To use external SIP clients: To use the WebRTC Bar: To run the Omnichannel web interface: Browser compatibility In particular, the application has been tested with minimum Google Chrome (v46) and Firefox (v41.0.2) on Windows (8.1/10) and Mac OS (Yosemite/El Capitan/Sierra/High Sierra). You can use Microsoft Edge 25.10586 (tested on Windows 10), for external SIP clients and Phonebar only If you use Firefox, please enable the Web Components feature: 
Server side requirements
Keep in mind that during your XCALLY operations some other parameters must also be considered, such as the maximum number of queues per agent, IVR complexity, the use of external APIs etc ...: the growth of any of these parameters could lead to redefine server requirements.
Scalability architecture is
recommended: see please HERE
Scalability architecture is
recommended: see please HERE
How to scale
For large scalable deployments and to be able to interact with the Motion DB from external application - without affecting the operation - we suggest at least 2 or 3 Linux CentOS7.X servers, like in the following examples.
Client side requirements
https://developer.mozilla.org/en-US/docs/Web/Web_Components#Enabling_Web_Components_in_Firefox