Senior Rust Engineer in Freienbach

Senior Engineer (80-100%)

Threema is the world's best-selling secure messenger for both private users and businesses.

Since 2012, we have been working tirelessly to ensure that our users can communicate freely without worrying about their privacy.

Our growing user base includes millions of private customers and thousands of businesses and organizations from all over the world.

• We are growing and looking for a new team member to join as a
• Senior Engineer Backend (80-100%)

The role

We're looking for a senior engineer to help design and build the core services behind our messaging backend.

You'll work on the systems that handle message delivery, real-time presence, and end-to-end encryption at scale.

Most of our backend is written in , and we're expanding it further.

You'll join a small team of engineers who care about correctness, performance, and keeping things simple.

Expect to write production code, review other people's code, and have a say in architecture decisions from day one.

What you'll do

• Design and build backend services in that handle high-throughput, low-latency messaging traffic
• Work on core infrastructure: message queues, delivery guarantees, connection handling, and storage layers
• Debug and optimize systems under real production load, not just in benchmarks
• Review code and mentor other engineers on patterns and systems design
• Take ownership of a service end to end, from design through deployment and maintenance

What we're looking for

• 10+ years of professional software engineering experience, with at least 2 years writing in production
• Solid understanding of concurrency, memory management, and systems programming
• Experience with distributed systems: what happens when a network partitions, a node dies, or a queue backs up
• Comfort working close to the metal when needed, whether that's networking, storage engines, or protocol design
• Experience in working on scalable, low-latency, high-throughput systems.
• communication skills. You'll need to explain trade-offs to people who don't write
• A degree in computer science or equivalent experience. We care more about what you've shipped than where you studied
• Nice to have
• Experience with async (Tokio or similar)
• Background in messaging protocols, telecom, or real-time systems
• Contributions to open source projects
• Experience with encryption or security-critical systems

What We Offer

• A young, motivated team with straightforward communication
• Flexible working hours, option to work from home up to two days per week
• Option to work from anywhere for two weeks per year
• Option to take unpaid leave
• You can choose your own hardware (mac OS or Linux)
• Public transportation discount or parking space (electric car charging available)
• Free use of fitness room, including a fitness trainer once a month
• Professional massage once a month
• Internal or English courses
• A great coffee machine ;-)
• Regular company events and aperitifs
• The good feeling of contributing to the effective protection of the privacy of millions of people
• Place of work: Pfäffikon SZ (Greater Zurich Area)

Have we sparked your interest?

We believe that diverse teams build better products.

We welcome and encourage applications from people of all backgrounds, and perspectives.

Your unique experience is an asset, and we'd love to hear from you.

Applications sent via email cannot be considered. Please use the official "Apply" button below so we don't accidentally miss your resume in our crowded inboxes

For agencies: we are filling this role directly and do not accept unsolicited candidate profiles.

• Hering
• Hering
• jidb84db8cjd jit0940jd jiy26jd