About Us

Threema is the world's best-selling secure messenger for both private users and businesses. Since 2012, we have been relentlessly committed to ensuring that our users can communicate without worrying about their privacy. Our growing user base includes millions of private customers and thousands of companies and organisations from all over the world.

Are you excited by developing application protocols for interactions between mobile apps and backend services? Are you interested in the security aspects of interaction flows? Are you an enthusiastic Rustacean? Then apply to us as:

Senior Software Engineer Protocols (m/f/x) (80-100%)

As an engineer in the protocols team, you will help us to further develop the core of Threema and contribute to the effective privacy protection of millions of people.

These tasks await you

• Build a deep understanding of the existing application and network protocols of the Threema ecosystem
• Design and specify new application and network protocols
• Implement protocol flows in libthreema, a Rust library that serves as the commoncore of future Threema apps
• Develop libthreema bindings for Android (Kotlin), iOS (Swift) and desktop(TypeScript / WASM)
• Perform code reviews within the development team

What you should ideally bring

Technical Experience

• Experience with the design and implementation of network and application protocols
• Extensive experience in software development, at least one year of practical experience with Rust
• At least a basic understanding of applied cryptography, ideally with practical experience in designing cryptographic protocols
• Enjoy high quality code (automated tests, linter, etc.)
• Bonus points for experience with secure programming techniques, cryptography, protocol buffers, sans I/O, mobile apps, algorithms, and data structures

Soft Skills

• High level of awareness when it comes to security and privacy issues
• Strong sense of responsibility and a careful way of working
• Ability to analyze complex problems and contexts and find creative solutions
• You can explain technical concepts clearly and precisely
• You can break down requirements and long-term goals into clear work tasks
• You are willing to familiarize yourself with new technologies and concepts and to keep learning
• Good written and spoken German and English (at least B2 level)

We are also happy to accept applications from people who meet many but not all of these criteria.

What We Offer

• A young, motivated team (±60 employees) with uncomplicated communication
• Work-life balance: flexible working hours, option to work from home on up to two days per week, up to two workation weeks per year

Benefits

• Free budget for computer/workstation (macOS or Linux)
• Public transport discount or parking space
• Electric car charging facility
• Free use of the company’s own fitness room incl. fitness trainer once a month
• Ping pong table
• Professional massage once a month
• Portafilter machine with free coffee from a local roastery
• Regular company events and after-work drinks

Have we sparked your interest?

We look forward to receiving your application documents by email or via Threema:

https://threema.com/en/jobs/senior-software-engineer-protocols

What We Need From You

To best process the applications we receive, we kindly ask you to include the following documents and information in your application:

• Salary expectations
• CV
• Earliest possible starting date

We like to keep our application process pragmatic, with a compact assessment in which you work on a practical programming task lasting around three hours.