Architecture & Scalability

Flexibility, scalability, and performance are the driving factors of the CELUM product architecture. They are manifested in a multi-server architecture approach, where each server has defined responsibilities. There are four server types working together.


The App Server is the central controller of the system and handles the users browsing the system and other clients like PC clients using the CELUM Desktop Tools (DTT). It is providing single sign-on (SSO) capabilities including Kerberos and SAML.

With a standard compliant BPMN business process engine, CELUM enables definition and management of workflows ranging from simple approvals to complex multi-department, parallelized processes.

Furthermore, the App Server allows easy integration with external systems by providing web services as SOAP API as well as a Java SDK for developing extensions that can be used to add new features at its core, including user interface extensions and user interface branding.


The Search Server is based on the enterprise search platform Apache Solr and offers powerful search and retrieval via the App Server user interface.


The Conversion Servers are responsible for extracting metadata from binary files and converting them to other formats. They can incorporate various conversion tools and are designed in an open fashion that allows fine grained configuration of each conversion step as well as the overall execution flow, resulting in a flexible conversion processes architecture.


The Storage Servers manage the access to data storage systems and support multiple data storage locations and strategies. They store and serve binary files in a secure manner using a state of the art URL signing mechanism to limiting the availability of files.

One of the available storage options is e.g. Amazon cloud based storage, available via an Amazon S3 connector, especially useful for Amazon load hosted systems.


In addition to those standard servers, the CELUM architecture offers an additional portal server, designed for maximum scalability. The CELUM servers are able to publish publicly available material directly to the portal in a secure way.

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