A Software Engineer at SIXT is responsible for designing, developing, and scaling the core systems that power one of the world's leading mobility providers. From real-time vehicle booking engines and dynamic pricing algorithms to global fleet management and payment integrations, engineering teams at SIXT solve complex physical-to-digital challenges. The code you write directly impacts millions of customers worldwide, ensuring seamless rental, ride-sharing, and car subscription services.

Operating at high scale, the engineering culture at SIXT emphasizes microservices, cloud-native architectures, and robust data pipelines. You will work in a highly collaborative environment where software development is viewed as a craft. Engineers are expected to take complete ownership of their services, from initial design and local development to deployment in production environments using modern DevOps toolchains.

Whether you are optimizing backend services in Munich or building frontend interfaces in Bengaluru, your work directly influences the company's digital transformation. The systems you build must remain highly available, secure, and low-latency, navigating the unique challenges of real-time supply and demand in the global transportation market.

The following questions represent patterns observed across actual SIXT technical interviews. While your specific questions may vary depending on the team and seniority level, preparing for these core topics will ensure you are well-positioned for success.

Data Structures & Algorithms

This category evaluates your core problem-solving speed, code optimization skills, and familiarity with standard algorithms.

• Reverse a singly linked list in-place and explain the time and space complexity.
• Find the height of a binary tree and write a function to delete a node from it.

To succeed in the SIXT interview process, you must demonstrate a balance of technical depth, system-level thinking, and collaborative problem-solving.

Technical Excellence – You must have a strong grasp of data structures, algorithms, and clean coding practices. Interviewers expect you to write clean, production-ready code during live sessions, with a strong focus on runtime and memory optimization.

System Design & Scalability – For mid-to-senior roles, you need to show that you can design systems that handle massive scale. You should be comfortable discussing microservices, message queues, caching strategies, and database indexing.

Adaptability & Tech Stack Agility – SIXT values engineers who are language-agnostic. While you will be evaluated on your core stack, you should express a willingness to learn and adapt to new technologies as business needs evolve.

Communication & Thought Process – Throughout the technical rounds, you are evaluated on how you articulate your thoughts. Explain your trade-offs clearly, ask clarifying questions, and walk the interviewer through your code using structured dry runs.

The interview process at SIXT is designed to thoroughly evaluate your technical capabilities, architectural thinking, and cultural alignment. The process is rigorous and typically spans several stages, ensuring that successful candidates possess both the depth and breadth required for the role.

The journey begins with an initial screening, which often includes a brief call with a recruiter followed by an online coding assessment. This assessment tests your algorithmic thinking and core programming skills under timed conditions. If you pass, you will move on to a series of technical interviews focusing on live coding, system design, and computer science fundamentals. The final stages involve behavioral discussions with hiring managers and directors to evaluate team fit and leadership potential.

The visual timeline above outlines the typical progression from your initial application to the final hiring decision. Use this sequence to pace your preparation, focusing first on algorithmic speed before transitioning into system design and behavioral scenarios.

Data Structures & Algorithms

Algorithmic problem-solving is a cornerstone of the technical evaluation at SIXT. Interviewers want to see how you approach unstructured problems, translate your logic into clean code, and optimize for performance.

Be ready to go over:

• Array and String Manipulation – Two-pointer techniques, sliding windows, and binary search implementations.
• Tree and Graph Traversals – Depth-First Search (DFS), Breadth-First Search (BFS), and tree manipulation algorithms.
• Dynamic Programming – Recognizing overlapping subproblems and building optimized bottom-up or top-down solutions.
• Advanced concepts (less common) – Custom data structure design (e.g., LRU cache) and complex pagination logic.

Example scenarios:

• "Given a binary tree, write an algorithm to delete a specific node while maintaining the tree's structural properties."
• "Write an optimized function to find the longest contiguous subarray that meets a specific mathematical condition."

System Design & Architecture

For engineering roles, system design rounds are crucial. You will be asked to architect high-availability systems, justify your technological choices, and address potential failure points.

Be ready to go over:

• Microservices & Event-Driven Architecture – Decoupling services using message brokers like Kafka.
• Caching & Data Storage – Choosing between SQL and NoSQL databases, and implementing caching layers with Redis.
• State Management & Hydration – Handling complex frontend state, Server-Side Rendering (SSR), and client-side rehydration.
• Advanced concepts (less common) – Designing global rate limiters and handling network partitions in distributed environments.

Example scenarios:

• "Design a real-time tracking system for a fleet of vehicles, ensuring low-latency updates for end-users."
• "Explain how you would migrate a monolithic booking system to a microservices-based architecture without downtime."

Language-Specific & Core CS Fundamentals

SIXT values engineers who understand what happens under the hood of their frameworks. This round deep-dives into the mechanics of your primary language and operating system concepts.

Be ready to go over:

• Concurrency & Memory Management – How your language handles garbage collection, multi-threading, and asynchronous operations.
• Object-Oriented Programming (OOP) – Design patterns, constructors, destructors, and SOLID principles.
• Database Internals – Transaction isolation levels, indexing strategies, and query optimization.
• Advanced concepts (less common) – Browser rendering engines, JS event loop mechanics, and JVM performance tuning.

Example scenarios:

• "Explain how the JavaScript engine executes asynchronous code and how polyfills are implemented for modern features."
• "Describe a scenario where a memory leak could occur in your primary language and how you would debug it."