Senior Software Engineer III (UI)

📍 Job Overview

Job Title: Senior Software Engineer III (UI) Company: OpenX Location: Krakow, Lesser Poland Voivodeship, Poland Job Type: Full-Time Category: Software Engineering (AdTech/MarTech Infrastructure) Date Posted: August 05, 2025 Experience Level: Mid to Senior-Level (5-10 years) Remote Status: Hybrid (Remote work option available)

🚀 Role Summary

• This role focuses on designing, architecting, and delivering high-performance, distributed, low-latency systems within the OpenX core exchange development team.
• Key responsibilities include enhancing consumer-grade user experience and design for enterprise-level applications and improving server efficiency, scalability, and stability.
• The position requires strong proficiency in JavaScript/Typescript (including Node.js) and experience with database system design, RDBMs, or NoSQL.
• Collaboration with cross-functional, globally distributed teams (Product, UX, Engineering) is essential for driving requirements and end-to-end project ownership.

📝 Enhancement Note: While the title is "Senior Software Engineer III (UI)", the core responsibilities and technical requirements heavily emphasize backend and infrastructure development for a high-throughput ad exchange. The "UI" aspect appears to be more about bringing consumer-grade user experience to enterprise tools rather than direct front-end UI development. This role is critical for the operational backbone of OpenX's advertising marketplace.

📈 Primary Responsibilities

• Architect, develop, and deploy new features and functionalities for OpenX's high-scale ad exchange platform, ensuring optimal performance and reliability.
• Design and implement distributed, low-latency systems capable of handling billions of ad requests daily, processing vast amounts of data efficiently.
• Collaborate closely with Product Management and UX Design teams to translate business requirements into robust technical solutions and deliver a seamless user experience for internal and external tools.
• Analyze and optimize the efficiency, scalability, and stability of existing servers and operational processes, proactively identifying and addressing potential bottlenecks.
• Take ownership of projects from conception through to deployment, ensuring long-term maintainability and avoiding "band-aid" solutions.
• Identify and eliminate unnecessary complexity within systems and workflows to drive operational excellence.
• Contribute to the continuous improvement of the cloud-based platform (GCP) and deployment pipelines, aiming for high velocity and stability.

📝 Enhancement Note: The responsibilities highlight a blend of system architecture, performance optimization, and cross-functional collaboration, typical of senior engineering roles in high-scale, real-time systems like ad exchanges. The emphasis on "consumer-grade user experience" for "enterprise" suggests a focus on internal tooling or developer portals.

🎓 Skills & Qualifications

Education:

• Bachelor's or Master's degree in Computer Science, Engineering, or a related technical field, or equivalent practical experience.

Experience:

• 4+ years of professional experience building robust SaaS applications.
• Proven track record in designing and implementing distributed systems with a focus on low-latency and high-throughput.
• Experience in data processing at scale, preferably within real-time or near-real-time environments.

Required Skills:

• Proficiency in JavaScript/Typescript: Deep understanding and practical application of these languages, including experience with Node.js for backend development.
• Database System Design: Strong knowledge of relational database systems (RDBMS) and/or NoSQL databases, including schema design, performance tuning, and data modeling.
• System Architecture: Ability to design scalable, fault-tolerant, and high-performance distributed systems.
• Cloud Computing Fundamentals: Familiarity with cloud environments (GCP is a plus, but general cloud concepts are key).
• Problem-Solving: Excellent analytical and problem-solving skills with a methodical approach to identifying and resolving complex technical challenges.
• Communication: Excellent written and spoken English proficiency for effective collaboration with global teams.
• Process Improvement: Ability to analyze and improve efficiency, scalability, and stability of servers and processes.

Preferred Skills:

• Google Cloud Platform (GCP): Hands-on experience with GCP services relevant to building and deploying large-scale applications.
• Amazon Web Services (AWS): Experience with AWS services is also a valuable asset.
• Digital Media/AdTech/MarTech: Prior experience working within the digital advertising, marketing technology, or media technology industries.
• Polish Communication: Communicative Polish language skills for local team integration.
• Containerization Technologies: Experience with Docker and Kubernetes for deployment and orchestration.

📝 Enhancement Note: The required skills clearly point towards a backend-heavy role with strong system design capabilities. The mention of "UI" in the title is likely a misdirection or refers to the user-facing aspects of internal tools rather than direct customer-facing front-end development. Candidates should highlight their experience with high-scale, real-time data processing and distributed systems.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• System Design Case Studies: Demonstrations of designing complex, scalable, and high-performance distributed systems, detailing trade-offs and architectural choices.
• Performance Optimization Examples: Case studies showcasing improvements in latency, throughput, or resource utilization for existing systems.
• Database Schema Design: Examples of efficient database schema design for large-scale applications, highlighting considerations for scalability and performance.
• Project Ownership & Delivery: Evidence of successfully owning and delivering complex features or projects end-to-end, from requirements gathering to deployment and maintenance.
• Code Samples: Well-structured and documented code samples (e.g., on GitHub) demonstrating proficiency in JavaScript/Typescript and Node.js.

Process Documentation:

• Workflow Design and Optimization: Showcase examples of how you've analyzed and improved operational workflows, server processes, or system efficiency.
• Scalability and Stability Enhancements: Documentation illustrating contributions to making systems more scalable and stable, including metrics and impact.
• Feature Development Lifecycle: Examples of your involvement in the full software development lifecycle, from requirement definition to production deployment and monitoring.

📝 Enhancement Note: For this role, a portfolio should heavily emphasize system design, performance optimization, and experience with high-volume data processing. Candidates should be prepared to walk through their architectural decisions, trade-offs, and the measurable impact of their work on system performance and efficiency.

💵 Compensation & Benefits

Salary Range:

• Employment Contract: 17,000 - 19,000 PLN gross per month.
• B2B Contract: 139 - 155 PLN net per hour.

📝 Enhancement Note: The provided salary range is for the gross monthly salary on an employment contract in Poland. For B2B, the hourly net rate is specified. These figures are competitive for senior software engineering roles in Krakow, especially within the AdTech sector, reflecting the specialized skills and high-scale environment at OpenX.

Benefits (on employment contract):

• Performance Bonus: Annual performance-based bonus.
• Tax Benefits: 75% tax-deductible system due to copyright protection.
• Health & Insurance: Private healthcare for employee and family, private life and travel insurance.
• Lifestyle & Wellness: MultiKafeteria program, access to peer-to-peer recognition platform.
• Learning & Development: Access to LinkedIn Learning platform and tech workshops.
• Time Off: Holiday allowance, additional paid day off.
• Financial Security: Pension scheme (PPK from PZU).
• Work Environment Support: Monthly work-from-home allowance and a one-time payment for home office setup.
• Perks: Free parking lot, recognition for personal milestones.

Working Hours:

• Standard working hours are approximately 40 hours per week, with flexibility offered.
• OpenX offers flexible working hours and a remote work option, accommodating different time zones and work-life balance needs.

📝 Enhancement Note: The benefits package is comprehensive, offering a mix of financial incentives, health and wellness programs, and professional development opportunities. The tax-deductible system due to copyright protection is a significant perk specific to Polish employment law. The flexible working hours and remote option demonstrate a commitment to employee well-being and modern work practices.

🎯 Team & Company Context

🏢 Company Culture

Industry: Digital Advertising Technology (AdTech) Company Size: Large (OpenX is a significant player in the AdTech space, likely employing several hundred to over a thousand employees globally). Founded: 2008 (This indicates a mature company with established processes but also a history of innovation and growth in a rapidly evolving industry).

Team Structure:

• Core Exchange Development Team: This role sits within a specialized team responsible for the core infrastructure that handles billions of ad requests daily.
• Global Collaboration: The team is distributed across multiple locations, requiring strong communication and collaboration skills with engineers, product managers, and UX designers in different regions.
• Reporting: While not explicitly stated, senior engineers typically report to an Engineering Manager or Director, with close collaboration with Product Managers and Tech Leads.

Methodology:

• Cloud-Native Operations: The platform is 100% cloud-based (GCP), implying a strong focus on cloud-native architectures, CI/CD, and DevOps practices.
• High-Velocity Deployments: Over 1200 production deployments per month suggest a mature CI/CD pipeline and a culture of rapid iteration and continuous integration.
• Data-Driven Decisions: Given the scale of operations (billions of ad requests, petabytes of data), decisions are likely driven by rigorous data analysis and performance metrics.
• Focus on Efficiency and Scalability: The company's emphasis on handling massive scale with low latency points to a culture that prioritizes engineering excellence, performance optimization, and long-term system stability.

Company Website: https://www.openx.com/

📝 Enhancement Note: OpenX operates in the highly competitive and fast-paced AdTech industry. The company's focus on large-scale, real-time systems means that engineering excellence, efficiency, and robust infrastructure are paramount. The culture likely values innovation, data-driven decision-making, and a collaborative approach to solving complex technical challenges at a global scale.

📈 Career & Growth Analysis

Operations Career Level: Senior Software Engineer III is a mid-to-senior individual contributor role. It implies a high level of technical expertise, autonomy, and the ability to mentor junior engineers. The "III" designation suggests a progression within senior levels.

Reporting Structure: Typically reports to an Engineering Manager or Tech Lead. Will work closely with Product Managers, UX Designers, and other engineering teams across different disciplines and geographies.

Operations Impact: This role directly impacts the core functionality and performance of OpenX's advertising exchange. Improvements in system design, latency, and efficiency have a direct effect on the company's ability to serve ads effectively, generate revenue, and maintain its market position. The role contributes to the operational backbone that enables the entire digital advertising ecosystem for OpenX's partners.

Growth Opportunities:

• Technical Specialization: Deepen expertise in high-scale distributed systems, cloud architecture (GCP), and real-time data processing within the AdTech domain.
• Leadership Development: Potential to move into Tech Lead or Architect roles, guiding technical direction for specific projects or system components.
• Mentorship: Opportunity to mentor junior engineers, contributing to team growth and knowledge sharing.
• Cross-Functional Exposure: Gain experience working with Product, UX, and other engineering teams, broadening understanding of the business and product lifecycle.
• Industry Expertise: Develop specialized knowledge in the complex and dynamic AdTech industry.

📝 Enhancement Note: The "Senior Software Engineer III" title suggests a significant level of responsibility and technical acumen. Growth opportunities are likely focused on deepening technical expertise in performance-critical systems and potentially moving into leadership or architectural roles within the engineering organization.

🌐 Work Environment

Office Type: OpenX offers a hybrid work model, with flexible working hours and the option for remote work. This suggests a blend of in-office collaboration and remote flexibility.

Office Location(s): While the primary posting is Krakow, OpenX has a global presence, indicating a diverse and potentially international team environment. The Krakow office likely serves as a significant engineering hub.

Workspace Context:

• Collaborative Engineering: Expect a collaborative environment where engineers work closely with Product Managers and UX Designers to define and build features.
• High-Tech Environment: Access to modern development tools, cloud infrastructure (GCP), and a focus on cutting-edge technologies in AdTech.
• Global Interaction: Opportunities to interact with colleagues from various global offices, fostering a diverse and inclusive work environment.

Work Schedule:

• The company offers flexible working hours, allowing engineers to adapt their schedules to optimize productivity and work-life balance.
• A standard 40-hour work week is expected, but the flexibility aims to accommodate personal needs and global team coordination.

📝 Enhancement Note: The hybrid and flexible work options indicate a modern approach to work, balancing the need for focused individual work (potentially remote) with collaborative team activities (potentially in-office). The environment is likely fast-paced and technically demanding, typical of the AdTech industry.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: HR or recruiter call to assess basic qualifications, cultural fit, and interest.
• Technical Screening/Online Assessment: May involve coding challenges or technical questions to evaluate core programming skills and problem-solving abilities.
• On-site/Virtual Interviews: Typically a series of interviews with engineering team members (peers, leads, managers). These will likely include:
  • System Design Interview: Focus on designing scalable, distributed systems, discussing trade-offs, and handling high-volume data.
  • Coding/Problem-Solving Interview: Practical coding exercises, potentially in JavaScript/Typescript, focusing on algorithms, data structures, and efficiency.
  • Behavioral Interview: Assessing alignment with OpenX values (We Are One, Customer Centric, OpenX Is Ours, Open Book, Evolve Fast) and traits (Humble, Driven, Smart). Questions will focus on past experiences, teamwork, conflict resolution, and handling challenges.
  • Product/UX Collaboration Discussion: Evaluating ability to work with non-engineering stakeholders and translate user needs into technical solutions.
• Final Interview: Potentially with a senior engineering leader or hiring manager to discuss overall fit and role expectations.

Portfolio Review Tips:

• Highlight System Design: Be prepared to present detailed diagrams and explanations for complex systems you've designed. Focus on scalability, latency, fault tolerance, and resource management.
• Quantify Impact: For any process or system improvements, provide concrete metrics (e.g., percentage reduction in latency, increase in throughput, cost savings).
• Showcase Code Quality: If sharing code samples, ensure they are well-organized, commented, and demonstrate best practices in JavaScript/Typescript and Node.js.
• Demonstrate Collaboration: Be ready to discuss instances where you collaborated effectively with Product or UX teams to achieve project goals.
• Focus on Ownership: Emphasize your role in taking projects from inception to completion, demonstrating accountability and proactive problem-solving.

Challenge Preparation:

• System Design Scenarios: Practice designing systems like a URL shortener, a distributed cache, a real-time analytics dashboard, or a high-throughput API gateway. Consider scale, data storage, consistency models, and latency constraints.
• JavaScript/Node.js Proficiency: Brush up on Node.js event loop, asynchronous programming patterns, common libraries, and performance tuning techniques.
• Database Concepts: Review RDBMS and NoSQL concepts, including indexing, query optimization, ACID properties, and CAP theorem.
• OpenX Values and Traits: Understand the company's core values and traits. Prepare examples from your career that demonstrate these qualities in action.

📝 Enhancement Note: Candidates should prepare thoroughly for system design and behavioral interviews, aligning their responses with OpenX's stated values and traits. Demonstrating a deep understanding of distributed systems, performance optimization, and collaborative problem-solving will be key.

🛠 Tools & Technology Stack

Primary Tools:

• Programming Languages: JavaScript/Typescript, Node.js
• Databases: RDBMS (e.g., PostgreSQL, MySQL) and NoSQL databases (e.g., Cassandra, MongoDB, DynamoDB)
• Cloud Platform: Google Cloud Platform (GCP) is a significant focus, though AWS experience is also valuable.
• Containerization: Docker, Kubernetes (likely used for deployment and orchestration)
• Version Control: Git

Analytics & Reporting:

• Monitoring & Logging: Tools like Prometheus, Grafana, ELK Stack (Elasticsearch, Logstash, Kibana), or similar cloud-native monitoring solutions.
• Data Processing: Potentially tools for large-scale data processing like Apache Spark, Flink, or cloud-specific services.
• CI/CD: Jenkins, GitLab CI, GitHub Actions, or similar for automated builds, testing, and deployments.

CRM & Automation:

• While not directly customer-facing in this role, understanding how the exchange integrates with advertising platforms and potentially CRM-like systems for partner management might be relevant.
• API Gateways: For managing and securing API traffic.
• Message Queues: Kafka, RabbitMQ, or similar for asynchronous communication between services.

📝 Enhancement Note: Proficiency in JavaScript/Typescript and Node.js is paramount. Experience with GCP and large-scale data handling is highly desirable. Familiarity with containerization and CI/CD pipelines is expected for this high-velocity environment.

👥 Team Culture & Values

Operations Values:

• We Are One: Emphasizes teamwork, mutual respect, and shared success across diverse individuals and global teams. This translates to collaborative problem-solving and supporting colleagues.
• Customer Centric: Focus on understanding and solving customer problems through innovation and honest partnerships. For this role, "customers" could include internal teams relying on the exchange infrastructure and external demand/supply partners.
• OpenX Is Ours: Fosters a sense of ownership and accountability. Team members are encouraged to take initiative, drive results, and contribute to improving the company.
• Open Book: Promotes transparency, knowledge sharing, and continuous learning. Expect a culture where asking questions and sharing expertise is encouraged.
• Evolve Fast: Encourages responsible risk-taking, learning from mistakes, adapting to change, and maintaining a sense of urgency in growth and learning.

Collaboration Style:

• Cross-Functional Integration: Close collaboration with Product, UX, and other engineering teams is fundamental. Expect regular communication and joint problem-solving sessions.
• Feedback Culture: The "Evolve Fast" value implies a culture that actively seeks and provides constructive feedback to drive continuous improvement.
• Knowledge Sharing: The "Open Book" value suggests a supportive environment where team members share technical knowledge and best practices, potentially through internal presentations, documentation, or pair programming.

📝 Enhancement Note: OpenX's values and traits are central to its culture. Candidates should be prepared to demonstrate how they embody these principles in their daily work, particularly "We Are One," "Open Book," and "Evolve Fast," which directly influence team dynamics and operational approaches.

⚡ Challenges & Growth Opportunities

Challenges:

• Scale and Performance: Working with billions of requests daily presents continuous challenges in maintaining low latency, high throughput, and system stability.
• Complexity of AdTech: The AdTech ecosystem is complex, with evolving standards, privacy regulations, and competitive pressures that require constant adaptation.
• Distributed Team Dynamics: Effectively collaborating with globally distributed teams requires strong communication skills and the ability to navigate different time zones and working styles.
• Balancing Innovation and Stability: The need to quickly implement new features while ensuring the stability and reliability of a mission-critical system is a constant balancing act.

Learning & Development Opportunities:

• AdTech Domain Expertise: Deepen understanding of programmatic advertising, market dynamics, and the technical intricacies of ad marketplaces.
• Advanced System Design: Gain hands-on experience with cutting-edge technologies for high-scale, real-time data processing and distributed systems.
• Cloud Architecture Mastery: Enhance skills in GCP or other cloud platforms, focusing on building resilient and scalable infrastructure.
• Mentorship and Leadership: Opportunities to grow into technical leadership roles, guiding projects and mentoring junior engineers.
• Industry Conferences & Training: Access to learning resources like LinkedIn Learning and tech workshops, potentially including industry events.

📝 Enhancement Note: The primary challenges revolve around managing extreme scale and complexity within a dynamic industry. Growth opportunities are substantial for engineers who thrive in such environments and seek to deepen their expertise in high-performance computing and cloud technologies.

💡 Interview Preparation

Strategy Questions:

• System Design: "Design a system to handle 100 billion ad requests per day with sub-100ms latency." Focus on architecture, data flow, caching strategies, load balancing, and fault tolerance.
• Scalability & Performance: "How would you diagnose and resolve a latency issue in a distributed microservices environment?" Prepare to discuss monitoring tools, profiling techniques, and bottlenecks.
• Collaboration & Ownership: "Describe a time you disagreed with a Product Manager on feature requirements. How did you resolve it?" "Tell me about a complex project you owned from start to finish."
• Problem-Solving: "Given a scenario where system throughput has dropped unexpectedly, what steps would you take to identify the root cause?"

Company & Culture Questions:

• Values Alignment: "Can you give an example of how you've embodied the 'We Are One' value?" "How do you ensure you 'Evolve Fast' in your work?"
• Teamwork: "Describe your ideal team environment." "How do you provide and receive constructive feedback?"
• Ownership: "Tell me about a time you took initiative to improve a process or system outside your direct responsibilities."

Portfolio Presentation Strategy:

• Structure Your Case Studies: For each case study, clearly outline the problem, your proposed solution (architecture diagrams are key), the trade-offs you considered, the challenges faced, and the measurable results.
• Quantify Everything: Use numbers and metrics wherever possible to demonstrate the impact of your work.
• Be Ready for Deep Dives: Anticipate detailed questions about your design choices, the technologies you used, and why you made specific decisions.
• Showcase Code (if applicable): Be prepared to walk through code samples, explaining your logic, efficiency considerations, and testing strategies.
• Connect to OpenX: Where possible, relate your experience and solutions to the challenges OpenX faces (high scale, low latency, AdTech specific problems).

📝 Enhancement Note: Preparation should focus on demonstrating technical depth in system design and performance optimization, alongside strong behavioral examples that align with OpenX's culture. Quantifying achievements is critical for showcasing impact.

📌 Application Steps

To apply for this operations position:

• Submit your application through the provided job link on lever.co.
• Tailor Your Resume: Highlight experience with JavaScript/Typescript, Node.js, distributed systems, database design, and cloud platforms. Quantify achievements related to performance, scalability, and efficiency.
• Prepare Your Portfolio: Curate your strongest examples of system design, performance improvements, and project ownership. Ensure you can clearly articulate the problem, solution, and impact.
• Research OpenX: Understand their business in AdTech, their scale, and their company values. Prepare to discuss how your skills and experience align with their mission.
• Practice Interview Questions: Rehearse answers to common system design, behavioral, and technical questions, focusing on demonstrating the "Humble, Driven, Smart" traits and OpenX values.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.