Senior Software Developer Java/PHP – PKI & Trustcenter

Project overview

For a project in the area of digital certificates and trust services, we are looking for an experienced Senior Software Developer (m/f/d) with a focus on Java and PHP.

Responsibilities

You will oversee the replacement of an existing electronic archiving system with a modern successor system. Your activities include analyzing the existing system, developing a migration concept, and providing technical support for data migration. Furthermore, you will analyze, specify, and implement components and system architectures in the area of digital certificates. You will design and develop order management systems for certificate products using agile methods and evaluate functional and non-functional requirements.

Requirements

You have at least 3 years of professional experience in PHP (version 5+) and Java. At least 3 years of practical experience in Public Key Infrastructure (PKI) and in the Trustcenter environment (certified data center operation) are essential. You have very good German language skills (C2 level or native speaker) and English at B2 level. Three reference projects from the last 48 months, each lasting at least 3 months, demonstrating your competencies in the mentioned areas are required.

Advantageous are experiences with refactoring of existing systems, SOAP/WSDL/XSD, shop systems, MySQL, as well as document or archive migration.

Framework Conditions:

Project details

December 2026 (at the latest January 2027), duration until December 2028. Scope: approx. 150 person-days over the entire duration, flexible call-off (not a full-time position). Predominantly remote with presence in Berlin at the beginning and end of the project. Activity must be carried out from Germany; access from abroad is not permitted.

• Start: Dezember 2026 (spätestens Anfang Januar 2027)
• Duration: 25 Monate
• Remote: onsite
• Location: Berlin, DE
• Languages: German, English