Senior Full Stack / Backend Developer (w/m/d)

At Appfire, we believe that great work happens when people get to choose how they work. After 20 years of creating software that empowers teams to break silos and collaborate seamlessly, we've learned that one size does not fit all. We're a team of 800+ employees, working remotely across 28 countries. Our flagship products include: Appfire Flow, JXL, Comala Document Management, 7Pace Time Tracker, Jira Misc Workflow Extensions, and BigPicture.

Here you can read some of our customer stories: https://appfire.com/resources/resource\-library/customer\-stories

About the role
Appfire is looking for a Tech Lead - Fullstack Engineer to join the BigPicture team and help evolve a modern, cloud-based SaaS platform. You'll lead the design of new functionality, optimize existing services, and support systems used by thousands of tenants. This role is heavily rooted in backend expertise, requiring a profound understanding of Java, Spring, and AWS / Cloud technologies. Additionally, the ideal candidate must have the willingness and capability to look after the frontend layer (TypeScript, Angular, or React), bridging the gap to deliver end-to-end solutions.

You will be joining a mature engineering team working on BigPicture. Over the coming quarters, the team will be heavily focused on AI-driven initiatives, including areas such as AI chatbot capabilities, data quality improvements, and dynamic reporting. As a Tech Lead, you will also drive the adoption of modern AI-assisted development practices to boost team productivity. This role reports to the Engineering Manager and works cross-functionally with product, UX, and DevOps.

You can choose to work remotely from anywhere in Bulgaria.

What you'll do:

• Technical Leadership
  : Leading technical discussions, making architectural decisions and guiding a mature engineering team through upcoming AI-driven product initiatives.
• Core Backend Development
  : Designing, implementing, and optimizing complex, scalable backend functionalities using Java, Spring, and AWS.
• Frontend Feature Delivery
  : Taking ownership of the frontend layer using TypeScript and Angular or React to support fullstack product delivery.
• AI Initiatives Execution
  : Leading the technical implementation of upcoming AI features, specifically focusing on AI chatbot capabilities, data quality improvements, and dynamic reporting.
• AI-Assisted Development
  : Actively using and promoting modern AI developer tools (e.g., Cursor, Claude) to maximize efficiency and modernize engineering workflows.
• Quality Assurance
  : Ensuring high code quality through rigorous testing (unit, integration, e2e), conducting peer code reviews, and solving performance-related challenges.
• Collaboration
  : Partnering closely with Product Owners, UX/UI designers, and other engineering teams.

Technical Highlights:

• Add your value to a complex yet well-designed application (BigPicture), having over 100 modules and fully-fledged Domain-Driven Design (ubiquitous language, aggregates, domain events etc.).
• Practice your craftsmanship in good design (clean code, SOLID, Inversion of Control) and in various architectures (hexagonal, event-driven, pipes&filters, modular monoliths, microservices and more).
• Dive deep into a heavy backend stack built on Java and Spring, while utilizing AWS to scale our advanced cloud (SaaS) architecture serving thousands of tenants.
• Work across the full stack by connecting robust backend services with modern frontend components using TypeScript, Angular, or React.
• Build cutting-edge AI features, including AI chatbots, automated data quality systems, and dynamic reporting tools.
• Supercharge your workflow using state-of-the-art AI tools like Cursor, GitHub Copilot, and modern LLMs for code generation, refactoring, and architectural brainstorming.
• Thoroughly test what you build: with unit, integration and e2e tests (Spock, JUnit, Mockito, AssertJ, REST Assured, WireMock, Testcontainers, Cypress).
• Feel safe with our extensive CI process that automatically runs unit, integration, e2e, architecture, migration and performance tests on your commit.

What you'll need:

• Technical Leadership:
  Proven experience acting as a Tech Lead, driving technical direction, making architectural choices, and mentoring senior/mid-level engineers.
• Strong Java & Spring Foundation:
  Deep, practical knowledge of Java, Spring, Hibernate, and SQL.
• Cloud & AWS Expertise:
  Strong understanding of SaaS architecture and extensive experience building/scaling applications within cloud environments, specifically AWS.
• Frontend Capability:
  Good hands-on skills in TypeScript and modern frameworks (Angular or React) combined with a genuine willingness to develop fullstack features.
• AI & Modern Tooling:
  High comfort level working with AI technologies, proficiency with AI-assisted development practices (specifically Cursor, Copilot), and an interest or background in implementing AI features (e.g., LLM integration, data indexing).
• Clean Code & Patterns:
  A good understanding of SOLID principles and common design patterns to keep the codebase maintainable.
• Testing & Tools:
  Proficiency in JUnit/Spock, Git, Maven, and Docker.
• Production-Ready Mindset:
  Experience in evolving and scaling established systems (beyond just greenfield projects) and a focus on long-term code maintainability.
• Performance Awareness:
  Ability to use profiling tools and a focus on writing efficient code that performs well under load.

Beyond the resume skills that match our culture and this role:

• You are dedicated to elevating client and co-worker experiences, knowing that exceptional work centers on serving others.
• You adapt swiftly to new business demands, understanding that change fuels collective and individual growth.
• You excel in communication, effectively connecting in remote/hybrid environments using tools like Slack, Zoom, and G Suite and through occasional in-person events.
• You have exceptional coaching, mentoring, and people development skills.

What we offer:

• Equity - Every Appfire team member is eligible for company equity, fostering a true sense of ownership and connection to our growth
• Paid time off - 25 paid days off regardless of your years of tenure. Increases to 30 days of annual leave per year after 5 years of employment 24 hours of paid volunteer time to engage in meaningful activities outside of work
• Training and personal development - Grow with Appfire University — our custom, on-demand learning platform designed to support your continuous development
• Health insurance - Private health insurance through UNIQA, fully paid by the company
• Multisport Card - The card is fully covered by Appfire
• Transport Card - Sofia City Transport Card, fully paid by Appfire, providing access to all modes of public transportation within the city
• Food vouchers - Pre-paid Pluxee lunch card with a monthly budget of 102,26 EURO
• Baby Bonus - To celebrate new additions to the family, employees receive a one-time net bonus of 511 EURO upon the birth of a child
• Volunteering - 3 fully paid days each year to participate in Appfire Town, our Corporate Social Responsibility (CSR) program supporting local communities
• Flexibility - The role is fully remote within Bulgaria, with the option to work from our Sofia office.

Market recognition
Appfire has been consistently recognized for company growth, culture, corporate social responsibility, and product excellence and has been included among the Deloitte Technology Fast 500, Inc. Best Workplaces, BuiltIn Best Places to Work, and Inc. 5000. Learn more about our accomplishments, which would not be possible without our team members, partners, and customers: https://appfire.com/awards.

Equal Employer Opportunity (EEO)
Appfire is an equal opportunity employer and does not discriminate based on race, color, religion, sex (including pregnancy), sexual orientation, gender identity or expression, national origin, age, disability, genetic information, marital status, veteran status, or any other protected characteristic as defined by applicable law. Our commitment extends to all employment practices, including recruitment, hiring, training, promotion, compensation, benefits, and termination.

Job Description
Job Title:
Java Developer

Job Type:
Contract

Location:
Remote

Job Summary:
As a Java Developer, you'll apply your expertise to help train next-generation AI systems. Your work will shape how models learn, reason, and perform through high-quality, real-world input. No prior experience in AI is required — your domain knowledge is what matters.

Key Responsibilities

• Design, develop, and maintain scalable backend systems using Java and Spring Boot.
• Architect robust microservices solutions to support complex application requirements.
• Collaborate with the customer's team to review technical specifications and deliver high-quality code.
• Contribute expert insights to improve application performance, reliability, and security.
• Participate in code reviews and provide constructive feedback to peers.
• Document technical processes and solutions with clear, concise written communication.
• Troubleshoot, debug, and optimize backend systems as needed.

Required Skills And Qualifications

• Expert proficiency in Java programming language.
• Hands-on experience with Spring Boot framework for backend development.
• Strong knowledge of microservices architecture and design principles.
• Demonstrated ability to write clean, maintainable, and efficient code.
• Exceptional written and verbal communication skills, with a keen attention to detail.
• Experience collaborating with remote teams in a fast-paced environment.
• Solid understanding of REST APIs, data structures, and backend best practices.

Preferred Qualifications

• Exposure to cloud platforms such as AWS, Azure, or Google Cloud.
• Prior experience working on AI-driven or data-intensive projects.
• Background in high-availability or distributed systems.

Job Description
Job Title:
Node.Js Developer

Job Type:
Contract

Location:
Remote

Job Summary:
In this role, you'll apply your expertise to help train next-generation AI systems. Your work will shape how models learn, reason, and perform through high-quality, real-world input. No prior experience in AI is required — your domain knowledge is what matters.

Key Responsibilities

• Leverage your deep knowledge of Node.js, JavaScript, and TypeScript to provide expert-level input and feedback for AI system development.
• Analyze and review code samples to ensure accuracy, efficiency, and adherence to best practices.
• Collaborate with multidisciplinary teams to identify key development patterns and problem-solving strategies in backend engineering.
• Evaluate real-world Node.js scenarios to help models learn robust, scalable, and maintainable solutions.
• Document insights, edge cases, and nuanced technical considerations in clear, effective written form.
• Contribute to model training by communicating complex concepts in a way that's accessible for both technical and non-technical stakeholders.
• Uphold high standards of written and verbal communication with both internal and external partners.

Required Skills And Qualifications

• Extensive hands-on experience with Node.js, JavaScript, and TypeScript in professional environments.
• Expert problem-solving and debugging abilities within distributed application systems.
• Strong attention to detail in both code review and written documentation.
• Excellent written and verbal communication skills, with an emphasis on clarity and thoroughness.
• Deep understanding of backend application architectures and common development patterns.
• Demonstrated ability to analyze and articulate technical trade-offs and solutions.
• Proactive, collaborative approach to cross-functional teamwork.

Preferred Qualifications

• Prior experience contributing to AI-related projects or model training initiatives.
• Background in designing or maintaining large-scale, high-availability Node.js applications.
• Experience with remote collaboration and asynchronous communication tools.

Job Description
Job Title:
Node.Js Developer

Job Type:
Contract

Location:
Remote

Job Summary:
In this role, you'll apply your expertise to help train next-generation AI systems. Your work will shape how models learn, reason, and perform through high-quality, real-world input. No prior experience in AI is required — your domain knowledge is what matters.

Key Responsibilities

• Leverage your deep knowledge of Node.js, JavaScript, and TypeScript to provide expert-level input and feedback for AI system development.
• Analyze and review code samples to ensure accuracy, efficiency, and adherence to best practices.
• Collaborate with multidisciplinary teams to identify key development patterns and problem-solving strategies in backend engineering.
• Evaluate real-world Node.js scenarios to help models learn robust, scalable, and maintainable solutions.
• Document insights, edge cases, and nuanced technical considerations in clear, effective written form.
• Contribute to model training by communicating complex concepts in a way that's accessible for both technical and non-technical stakeholders.
• Uphold high standards of written and verbal communication with both internal and external partners.

Required Skills And Qualifications

• Extensive hands-on experience with Node.js, JavaScript, and TypeScript in professional environments.
• Expert problem-solving and debugging abilities within distributed application systems.
• Strong attention to detail in both code review and written documentation.
• Excellent written and verbal communication skills, with an emphasis on clarity and thoroughness.
• Deep understanding of backend application architectures and common development patterns.
• Demonstrated ability to analyze and articulate technical trade-offs and solutions.
• Proactive, collaborative approach to cross-functional teamwork.

Preferred Qualifications

• Prior experience contributing to AI-related projects or model training initiatives.
• Background in designing or maintaining large-scale, high-availability Node.js applications.
• Experience with remote collaboration and asynchronous communication tools.