> For the complete documentation index, see [llms.txt](https://docs.keyfax.biz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.keyfax.biz/technical/general/architecture.md).

# Keyfax Architecture

An overview of the Keyfax architecture.

## Keyfax Staff

Keyfax is designed as a three-tier application which is controlled (typically but not exclusively) by a Housing management System (HMS) host application that requires the ability to diagnose Repair or Enquiry data.

The following schematic describes the Keyfax V4.x architecture in a typical Call Centre environment:

<div align="left"><figure><img src="https://2882349412-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MARm6St_qFGM52R3pBa%2Fuploads%2FMHtPFLtkHdr4qu3m5wmG%2FKeyfax%20Architecture.png?alt=media&amp;token=987dadb8-5fa9-45cc-956a-ae446a61f575" alt=""><figcaption></figcaption></figure></div>

Note that a single Keyfax installation can support an infinite number of instances. In the above diagram, this is depicted by the two databases, two sets of scripts etc. Access to a particular instance is controlled by the passing of configuration data to Keyfax upon launch(i.e. Company Code).

Instances can also share the same database.

### Keyfax Self-Service

For self-service environments, Keyfax is usually launched via a client website or public facing portal:

<div align="left"><figure><img src="https://2882349412-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MARm6St_qFGM52R3pBa%2Fuploads%2FSnhhxgdk2G0JZYRLfV0m%2FKeyfax%20Architecture%20Online.png?alt=media&amp;token=1dab7c59-0077-4e92-989b-977f98e500eb" alt=""><figcaption></figcaption></figure></div>