Senior Software Engineer - Offline
Mendix is hiring a Senior Software Engineer - Offline in Rotterdam, Netherlands. It pays €69k-€111k a year and Level rates it ; you can apply on Mendix.
Level's read on this job
- Uses AI ●●○○ is how Level rates this software engineer role: an ordinary role that requires AI tools.
- Level classes it as a senior role.
- Mendix has 47 other open roles on Level.
AI in this role
About Us
We are a leading global software company dedicated to the world of computer aided design, 3D modeling and simulation— helping innovative global manufacturers design better products, faster! With the resources of a large company, and the energy of a software start-up, we have fun together while creating a world class software portfolio. Our culture encourages creativity, welcomes fresh thinking, and focuses on growth, so our people, our business, and our customers can achieve their full potential.
Position Overview
Join our Runtime & Client group as a Senior Software Engineer and help shape the future of offline-first application development. You'll work on the offline capabilities that power Mendix mobile and web apps—building the foundation that enables applications to keep running when there's no network connection. From local data storage and background synchronization to conflict resolution when devices reconnect, you'll solve complex technical challenges and make them simple for developers and non-technical users alike. Working across the full stack—client-side runtime, server-side synchronization, and developer tooling—you'll have the opportunity to connect the dots and create resilient, offline-capable experiences that matter.
Key Responsibilities
• Design, develop, and maintain offline runtime components and synchronization layers that power Mendix applications across web and mobile platforms
• Implement and optimize data synchronization strategies, including conflict detection and resolution mechanisms between offline clients and backend systems
• Collaborate across the full product stack—from client-side runtime code to server-side logic to Studio Pro tooling—to deliver cohesive offline-first experiences
• Mentor team members and contribute to technical architecture decisions that balance complexity with usability for developers and end users
• Participate in code reviews, testing, and quality assurance to ensure robust, performant solutions that meet production standards
• Stay current with emerging web technologies, offline-first patterns, and browser APIs to continuously improve our platform
Qualifications:
Required:
• Expert-level proficiency in JavaScript/TypeScript with a strong understanding of offline-first patterns and browser storage APIs (such as Origin Private File System or service workers)
• Proven experience designing or implementing data synchronization strategies, including conflict detection and resolution mechanisms
• Ability to work across multiple areas of a product—from client-side runtime to server-side synchronization to developer tooling—and connect those dots effectively
• Demonstrated commitment to quality and a sense of responsibility for the impact your work has on developers and end users who depend on it
• Minimum 6 years of professional software development experience
Preferred:
• Experience with Progressive Web Apps (PWAs) or React Native and understanding of offline challenges specific to mobile environments
• Knowledge of WebAssembly (WASM), including its performance characteristics and browser compatibility constraints
• Experience with JVM-based languages (Scala, Java, or Kotlin) relevant to runtime synchronization layers
• Familiarity with C# or .NET, relevant to Studio Pro development
• Background building or working with low-code or no-code platforms
• Experience with cross-stack testing frameworks such as Jest, WebdriverIO, or similar tools
Why Us
At Siemens Software, flexibility is how we work—hybrid by default, built on trust and autonomy. Together, 30,000 people across more than 200 countries build technology that shapes the real world. You'll grow through real projects, strong technical peers, and global mobility, backed by the scale and benefits of an industrial software leader. We're committed to equality and inclusion, and we hire based on merit, skills, and impact. Bring your curiosity and creativity and help us shape tomorrow!
Our Benefits & Rewards
The salary range for this position is €69,100 to €110,600 and this role is eligible to earn incentive compensation. The actual compensation offered is based on the successful candidate's job-related skills, experience, and relevant education/training. Siemens offers health and wellness benefits to employees; you can access the benefits available in your country via the link: https://jobs.sw.siemens.com/benefits/
Diversity & Inclusion
We value equal opportunities and welcome applications from people with disabilities. At Siemens, we believe people who've had real experiences dealing with being different will excel as leaders. Let's foster a culture of creativity and innovation. We will ensure that individuals with disabilities are provided reasonable accommodation to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment. Please contact us to request accommodation.
Siemens Software. Transform the Everyday
#LI-Hybrid #SaaS
How we rate this
Senior Software Engineer - Offline at Mendix rates 44 out of 100 for how much of the daily work is AI. That makes it Uses AI (AI Level 2 of 4). The level is about AI in the job, not seniority.
Uses AI. An ordinary role that requires AI tools.
- ●●●● Builds AI80 to 100
- ●●●○ Works on AI60 to 79
- ●●○○ Uses AI40 to 59
- ●○○○ Little AI0 to 39
Levels come from how often the tools, models and workflows of the role are named in the posting itself. Read the description and count the AI tools, models and workflows it names.
Prepare for this job
Built from this posting and from similar jobs on Level.
Pay
- Typical software engineer job
- $167k
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