Senior Full Stack Engineer - Core UX

📍 Job Overview

Job Title: Senior Full Stack Engineer - Core UX

Company: Jobgether (Partner Company)

Location: Germany

Job Type: Full-time, Contractor (B2B)

Category: Engineering, Software Development, User Experience (UX)

Date Posted: 2026-09-30

Experience Level: 5-10 Years

Remote Status: Fully Remote

🚀 Role Summary

• This role is for a Senior Full Stack Engineer focused on Core User Experience (UX) within a sophisticated, business-critical software environment.

• Key responsibilities include refining existing functionality, enhancing usability, and ensuring visual quality and responsiveness of the user interface.

• The position requires a blend of strong frontend expertise and full-stack engineering skills to tackle complex product and technical challenges.

• Candidates will collaborate with a diverse team of engineers (full-stack, data, ML, DevOps) to build scalable solutions in a global, collaborative setting, with significant individual ownership and impact on product quality and business outcomes.

📝 Enhancement Note: While the title is "Senior Full Stack Engineer - Core UX", the provided description and requirements strongly indicate a role focused on enhancing existing user interfaces and backend systems rather than building new UX features from scratch. The emphasis on "refine and improve existing product functionality" and "strengthen consistency" points towards a role that acts as a guardian of user experience quality and technical robustness within the core application. The "Contractor (B2B)" employment type is a crucial detail for candidates to note, as it implies a business-to-business engagement rather than direct employment.

📈 Primary Responsibilities

• Refine and elevate existing product functionality, prioritizing usability, consistency, responsiveness, performance, and visual appeal.

• Develop and maintain scalable full-stack solutions that underpin reliable, high-quality user experiences.

• Implement intricate frontend interactions and layouts, ensuring a seamless and cohesive experience across the entire product.

• Engage in cross-functional collaboration with full-stack, data, machine learning, and DevOps engineers to advance product capabilities.

• Contribute to critical areas such as system design, debugging, performance optimization, and overall technical problem-solving across the application stack.

• Assume complete ownership of assigned projects, guiding initiatives from conceptualization through implementation and final delivery with minimal supervision.

• Drive innovation through experimentation with various technical and product approaches, rigorously measure outcomes, and iterate rapidly to enhance functionality and user impact.

• Maintain proactive communication with stakeholders, effectively surface blockers, articulate pertinent questions, and provide clear, consistent project updates.

• Contribute to the development of scalable cloud-based architectures, asynchronous workflows, and robust backend solutions as the product ecosystem expands.

📝 Enhancement Note: The responsibilities emphasize a strong focus on iterative improvement and ownership, common in growth-stage companies or teams responsible for mature products needing continuous enhancement. The mention of "scalable cloud-based architectures, asynchronous workflows, and reliable backend solutions" indicates that this role is not solely front-end focused but requires a solid understanding of backend infrastructure and scalability principles.

🎓 Skills & Qualifications

Education: Not specified, but a Bachelor's or Master's degree in Computer Science, Engineering, or a related field is typically expected for senior engineering roles.

Experience: 5+ years of professional software engineering experience, with a demonstrated history of improving and polishing product functionality and user experiences.

Required Skills:

• Strong engineering fundamentals in system design, debugging, architecture, and problem-solving.

• Professional experience with a modern frontend framework, specifically React.

• Proficient programming experience in JavaScript, TypeScript, or Python; strong object-oriented programming (OOP) backgrounds will also be considered.

• Experience with cloud and serverless technologies, such as AWS Lambda and EC2, and familiarity with asynchronous workflows and cloud-based environments.

• Comfortable working with relational databases, with a preference for PostgreSQL experience.

• A strong ownership mindset, enabling independent project drive and maintenance of high-quality standards.

• Proactive and transparent communication style, essential for effective collaboration in a distributed international setting.

• Adept at experimenting, testing ideas, measuring results, and iterating rapidly on complex or unfamiliar challenges. Preferred Skills:

• Experience with Large Language Models (LLMs), generative AI, or distributed systems.

• Familiarity with other backend technologies or databases.

• Experience working in a growth-stage or startup environment.

• Understanding of UX principles and best practices beyond technical implementation.

📝 Enhancement Note: The "5+ years" experience level aligns with a senior engineering position, suggesting candidates should be prepared to mentor junior engineers and contribute to technical strategy. The preference for React and specific AWS services points to the core technology stack the candidate will interact with daily. The mention of Python and OOP as alternatives to JavaScript/TypeScript broadens the scope for candidates with strong backend or general software engineering foundations.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Demonstrate projects showcasing iterative UI refinement and performance optimization, highlighting before-and-after metrics.

• Include examples of full-stack development projects that highlight system design, scalability, and integration with cloud services (e.g., AWS Lambda, EC2).

• Present case studies of complex technical problems solved, emphasizing debugging, root cause analysis, and the implementation of robust solutions.

• Showcase contributions to asynchronous workflows or backend service development, detailing architecture and implementation choices.

• Provide evidence of working with relational databases, ideally demonstrating PostgreSQL schema design or query optimization. Process Documentation:

• Candidates are expected to articulate their approach to system design, including architectural patterns and considerations for scalability and maintainability.

• Demonstrate understanding of debugging methodologies for both frontend and backend components, including tracing issues across distributed systems or asynchronous workflows.

• Be prepared to discuss processes for iterative development, A/B testing, and performance monitoring in a production environment.

📝 Enhancement Note: For a Senior Full Stack Engineer role, a portfolio should not just list projects but tell a story of impact. For this role, the emphasis should be on how the candidate's work directly improved user experience metrics (performance, usability, consistency) and contributed to the scalability and reliability of the backend systems. Demonstrating a proactive approach to problem-solving and ownership is key.

💵 Compensation & Benefits

Salary Range: Approximately $80,000–$165,000 USD per year. This range is dependent on candidate experience, performance, and geographic location.

Benefits:

• Significant equity options package, offering potential for substantial long-term financial gain.

• 20 days of paid time off (PTO) per year, providing ample opportunity for rest and rejuvenation.

• Global team offsites, fostering team cohesion and international networking opportunities.

• Phone reimbursement, contributing to communication expenses.

• Gym reimbursement, supporting employee health and wellness.

• Student stipend, potentially assisting with ongoing education or professional development.

• High level of ownership and the opportunity to make a substantial impact within a growth-stage environment.

Working Hours: Full-time (approximately 40 hours per week), with flexibility expected given the remote, international nature of the team. Specific working hours may vary based on individual agreements and team needs, but core collaboration hours will likely exist.

📝 Enhancement Note: The salary range is provided in USD, which is common for international remote roles, especially in tech. However, candidates located in Germany should research local market rates for comparable Senior Full Stack Engineer roles to understand how the USD range translates to local purchasing power and benefits. The B2B/contractor engagement model means benefits like health insurance and statutory leave may differ significantly from direct employment and will need to be managed by the contractor.

🎯 Team & Company Context

🏢 Company Culture

Industry: Technology, Software Development, Job Matching Platform (Jobgether). The partner company operates in a space that leverages technology to connect job seekers with opportunities, likely involving complex data processing, matching algorithms, and user-facing applications.

Company Size: Not explicitly stated, but described as a "growth-stage environment" and an "ambitious, international, and multidisciplinary team." This suggests a company that is past the initial startup phase, likely with established processes, but still agile and expanding.

Founded: Not specified, but the "growth-stage" description implies a relatively modern company, likely founded within the last decade, focused on scaling its operations and product.

Team Structure:

• The Core UX engineering team is a specialized unit within the broader engineering organization.

• This role will report to an engineering lead or manager and collaborate closely with other engineers across full-stack, data, ML, and DevOps disciplines.

• Cross-functional collaboration is a core aspect, involving interaction with product managers, designers, and potentially other stakeholders to define and deliver UX improvements. Methodology:

• Data-driven decision-making is a key aspect, with an emphasis on measuring outcomes and iterating based on results.

• Agile methodologies are likely employed, focusing on iterative development, rapid feedback loops, and continuous improvement.

• A strong emphasis on code quality, system design, and scalable architecture principles will guide development practices.

Company Website: https://jobgether.com/

📝 Enhancement Note: Jobgether itself acts as a platform utilizing AI for candidate matching. The partner company, for whom this role is, is the actual end-user of the engineer's skills. The description "sophisticated, business-critical software" suggests the partner company's product is complex and essential for its users' operations, making the UX and reliability of the Core UX team paramount.

📈 Career & Growth Analysis

Operations Career Level: Senior Full Stack Engineer. This level signifies a high degree of technical expertise, autonomy, and the ability to influence technical direction. Senior engineers are expected to solve complex problems independently, mentor others, and contribute to architectural decisions.

Reporting Structure: The role will likely report to an Engineering Manager or Lead who oversees the Core UX team. Collaboration will extend across various engineering disciplines and potentially product management.

Operations Impact: As a Senior Full Stack Engineer focused on Core UX, the impact is direct and significant. Improvements in usability, performance, and consistency directly affect user adoption, retention, and overall customer satisfaction, which in turn drives business success and revenue for the partner company. The role offers substantial ownership, meaning individual contributions have a clear line of sight to business outcomes.

Growth Opportunities:

• Deepen expertise in modern frontend frameworks (React) and full-stack development within a complex application.

• Gain exposure to advanced technologies like LLMs, generative AI, and distributed systems, as mentioned in preferred skills.

• Develop leadership skills by taking ownership of projects, potentially mentoring junior engineers, and contributing to technical strategy.

• Advance within the engineering hierarchy, potentially moving towards Lead Engineer, Architect, or Engineering Management roles within a growth-stage company.

• Benefit from a culture of continuous learning and experimentation, encouraging exploration of new technologies and methodologies.

📝 Enhancement Note: The "growth-stage environment" and "substantial ownership" suggest a dynamic career path where individuals can rapidly gain experience and influence. The focus on "iterative improvement, experimentation, and delivering a premium user experience" implies opportunities to hone skills in these specific, high-demand areas.

🌐 Work Environment

Office Type: This is a fully remote position. The engagement is offered on a B2B or contractor basis, meaning there is no central office to work from unless the contractor chooses to utilize co-working spaces at their own discretion.

Office Location(s): The role is based in Germany, and the candidate must be authorized to work in a European country. While the role is remote, adherence to local regulations and tax requirements for contractors in their country of residence is essential.

Workspace Context:

• The work environment is highly collaborative despite being remote, requiring proactive communication and engagement with a global team.

• Access to modern development tools, cloud infrastructure (AWS), and a robust technology stack is inherent to the role.

• Opportunities for interaction will primarily be through virtual channels (e.g., Slack, Zoom, project management tools), with a focus on transparent communication and shared understanding.

Work Schedule: Full-time employment, approximately 40 hours per week. While remote, the candidate must be able to align with core team working hours for effective collaboration, likely within European time zones. Flexibility is implied, but consistent availability for team syncs and project needs is expected.

📝 Enhancement Note: As a remote, B2B contractor role based in Germany, candidates must be aware of German labor laws and tax implications for self-employment or B2B contracting. This includes understanding VAT, income tax, and social security contributions, which are typically the responsibility of the contractor.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening (Jobgether AI): An AI-powered matching process reviews applications objectively against core requirements. Top candidates are shortlisted.

• Hiring Company Review: The shortlisted candidates' profiles are shared directly with the partner company's internal team.

• Technical Interview(s): Expect one or more technical interviews focusing on system design, coding challenges (potentially live coding), debugging scenarios, and in-depth discussion of past projects.

• Behavioral/Cultural Interview: Assessment of collaboration style, communication skills, problem-solving approach, and alignment with the company's growth-stage culture.

• Portfolio Presentation: Candidates will likely be asked to present specific projects from their portfolio, detailing their role, challenges faced, technical solutions implemented, and the impact of their work.

Portfolio Review Tips:

• Select 2-3 strong full-stack projects that best showcase your experience in refining existing functionality, improving performance, and implementing scalable backend solutions.

• For each project, clearly articulate your specific contributions, the technical stack used (especially React, JavaScript/TypeScript, Python, AWS), and the problem you solved.

• Quantify the impact of your work using metrics whenever possible (e.g., performance improvements in milliseconds, reduction in error rates, increase in user engagement).

• Be prepared to walk through code snippets or architecture diagrams to explain complex technical decisions.

• Highlight instances where you took ownership, experimented, and iterated to achieve a better outcome. Challenge Preparation:

• Brush up on core data structures and algorithms.

• Practice coding problems typical for senior full-stack roles, focusing on areas like API design, database interactions, and asynchronous processing.

• Prepare to discuss system design principles for scalability, reliability, and performance, particularly in a cloud environment (AWS).

• Review common UX principles and how to translate them into technical implementations.

• Be ready to discuss your experience with LLMs or generative AI if you have it.

📝 Enhancement Note: The AI screening by Jobgether means keywords and direct alignment with the requirements are crucial for initial visibility. The partner company manages the final stages, so tailoring your application and portfolio to their specific needs (as inferred from the job description) is vital.

🛠 Tools & Technology Stack

Primary Tools:

• Frontend Framework: React (highly preferred), JavaScript, TypeScript.

• Backend Languages: JavaScript, TypeScript, Python.

• Cloud Platform: AWS (specifically AWS Lambda, EC2).

• Databases: Relational databases, specifically PostgreSQL.

• Development Practices: Version Control (e.g., Git), CI/CD pipelines (likely).

Analytics & Reporting:

• Tools for monitoring application performance and user behavior (e.g., Datadog, New Relic, Google Analytics, or similar).

• Data analysis tools to interpret metrics and measure impact. CRM & Automation:

• While not explicitly mentioned for this role, understanding how the frontend and backend interact with CRM systems or other business applications is beneficial.

• Familiarity with workflow automation and orchestration, especially in cloud environments.

📝 Enhancement Note: The explicit mention of React, JavaScript/TypeScript, Python, AWS Lambda/EC2, and PostgreSQL forms the core of the expected technical stack. Candidates should be prepared to discuss their proficiency and experience with these technologies in detail.

👥 Team Culture & Values

Operations Values:

• Ownership: Taking full responsibility for projects and their outcomes, driving them to completion with high standards.

• Iteration & Experimentation: A willingness to try new approaches, measure results, and adapt quickly based on data.

• Collaboration: Working effectively with a diverse, international, and multidisciplinary team, fostering open communication.

• Quality & Polish: A commitment to delivering high-performing, visually appealing, and consistent user experiences.

• Impact-Driven: Focusing on delivering tangible results that contribute to business success and user satisfaction.

Collaboration Style:

• Proactive and transparent communication is paramount, especially in a remote, distributed team.

• Cross-functional teamwork is essential, requiring engineers to work closely with peers in different specializations.

• A culture of mutual respect and constructive feedback is likely valued, supporting continuous improvement.

• Knowledge sharing through documentation, code reviews, and team discussions is important for collective growth.

📝 Enhancement Note: The emphasis on "growth-stage environment" and "ambitious, international, and multidisciplinary team" suggests a culture that is fast-paced, innovative, and values individual contribution and initiative.

⚡ Challenges & Growth Opportunities

Challenges:

• Technical Complexity: Working with sophisticated, business-critical software means tackling intricate problems that require deep technical understanding and innovative solutions.

• Balancing Polish with Speed: Delivering a "premium user experience" while iterating rapidly in a growth-stage environment can be challenging, requiring efficient development practices.

• Cross-Functional Coordination: Effectively collaborating with diverse engineering teams and stakeholders across different time zones requires strong communication and project management skills.

• Maintaining Consistency: Ensuring a cohesive user experience across a growing product suite demands rigorous attention to detail and adherence to established design and technical patterns.

• Contractor Status: Navigating the responsibilities and potential differences in benefits and employment security compared to direct employment.

Learning & Development Opportunities:

• Specialization in core UX enhancement and full-stack development within a modern tech stack.

• Exposure to cutting-edge technologies like LLMs and generative AI, offering opportunities for upskilling.

• Developing leadership qualities through project ownership and potential mentorship.

• Gaining experience in a dynamic, growth-stage company, understanding how to scale products and teams.

• Networking with an international team, broadening professional perspectives.

📝 Enhancement Note: The challenges presented are inherent to senior roles in growth-stage tech companies, particularly those focused on product refinement and scalability. These challenges also serve as opportunities for significant professional development.

💡 Interview Preparation

Strategy Questions:

• Technical Strategy: "Describe a time you significantly improved the performance or usability of an existing feature. What was your approach, what metrics did you track, and what was the outcome?"

• Problem-Solving: "Walk us through a complex bug you encountered in a distributed system or asynchronous workflow. How did you diagnose it, what was the root cause, and how did you ensure it wouldn't recur?"

• Collaboration: "How do you balance the need for code quality and polish with the pressure for rapid iteration and delivery in a growth-stage environment?"

• System Design: "Design a scalable backend service for [a hypothetical feature relevant to the partner company's domain], considering database choices, API design, and cloud deployment."

Company & Culture Questions:

• "What interests you about working on Core UX for a product like ours?"

• "How do you approach collaboration with engineers from different disciplines (e.g., data science, ML)?"

• "Describe a situation where you had to take significant ownership of a project. What were the key challenges, and how did you overcome them?"

• "How do you stay updated on the latest trends in frontend development, backend technologies, and UX best practices?" Portfolio Presentation Strategy:

• Structure: For each project, use the STAR method (Situation, Task, Action, Result) or a similar narrative structure.

• Focus: Emphasize your specific contributions, the technical challenges, your problem-solving approach, and the measurable impact on users or the business.

• Visuals: Use diagrams, screenshots, or code snippets to illustrate your points effectively.

• Conciseness: Be clear and direct, respecting the interviewer's time. Practice your delivery to be confident and engaging.

• Tailoring: Connect your portfolio examples to the requirements and responsibilities outlined in the job description.

📝 Enhancement Note: Interviewers will be looking for evidence of strong technical skills, a proactive and ownership-driven mindset, excellent communication, and a genuine interest in improving user experience and contributing to the company's growth.

📌 Application Steps

To apply for this operations position:

• Submit your application through the provided Jobgether link.

• Portfolio Customization: Select 2-3 key projects that demonstrate your expertise in full-stack development, UI refinement, performance optimization, and cloud-native solutions. Ensure these projects highlight your ability to improve existing functionalities and drive measurable impact.

• Resume Optimization: Tailor your resume to emphasize keywords like React, JavaScript, TypeScript, Python, AWS Lambda, EC2, PostgreSQL, system design, debugging, and UX improvement. Quantify your achievements whenever possible.

• Interview Preparation: Practice articulating your project experience, technical solutions, and problem-solving methodologies. Prepare to discuss your approach to ownership, collaboration, and iterative development.

• Company Research: Understand Jobgether's mission and the likely domain of their partner company. Research growth-stage company dynamics and the importance of Core UX in such environments. Be prepared to discuss why you are interested in a B2B/contractor engagement.

⚠️ 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. As this is a B2B/contractor role, ensure you understand your tax and legal obligations in your country of residence.