Join ABC Fitness and become part of a culture that’s as ambitious as it is authentic. Let’s transform the future of fitness—together!
Our Values
We believe great work begins with great people. That’s why our culture is built on respect, trust, and belonging. We create an inclusive environment where every team member can bring their authentic self to work—because diverse perspectives drive innovation and meaningful impact.
We are doers, thinkers, and dreamers. At ABC Fitness, your growth is our investment. Through continuous learning, mentorship, and professional development opportunities, we empower you to reach new heights—personally and professionally.
From day one, you’ll be part of a team that collaborates, celebrates, and cares. We move fast, support one another, and have fun along the way. Because when you thrive, we all thrive.
Lead the architecture and hands-on modernization of critical software systems.
ABC Fitness is modernizing critical technology from legacy, database-centric applications toward well-designed, domain-oriented software. This role will provide principal-level technical leadership for that transformation while protecting compatibility, correctness, and business continuity.
As a Principal Engineer, you will set software architecture and engineering direction and remain close to implementation. You will work across application code, domain models, APIs, data access, messaging, runtime behavior, and tests to turn complex technical risk into durable software.
This is a hands-on individual-contributor role. You will influence teams through technical judgment, clear architecture, working software, production insight, and partnership not through direct people management.
Shape the evolution of legacy applications into well-structured, domain-oriented software. Define target architecture, module and service boundaries, migration seams, compatibility strategies, and incremental paths that teams can implement safely.
Contribute directly to critical implementations, prototypes, refactoring, code reviews, and production fixes. Work comfortably in backend code and frameworks such as Java/Springboot, Golang, Node/TypeScript, or similar backend ecosystems, and help teams improve application structure, runtime behavior, and maintainability.
Create clear domain abstractions, ownership boundaries, service contracts, and APIs. Improve how business rules are represented in code and keep consumers insulated from legacy storage and implementation details.
Guide framework and runtime upgrades, dependency modernization, concurrency and lifecycle improvements, and the decomposition of tightly coupled code. Use practical refactoring strategies that keep large systems releasable throughout the work.
Diagnose difficult behavior through code, runtime evidence, database interactions, and dependency flows. Fix root causes in implementation and design, including concurrency defects, inefficient data access, resource contention, failure propagation, and recovery behavior.
Move business logic out of database-centric implementations and into testable application code. Design effective persistence, transaction, caching, messaging, and event-consumer patterns while preserving historical, reporting, and audit needs.
Establish strong practices for unit, integration, contract, and functional testing. Improve code review, static analysis, dependency management, feature controls, and validation so teams can change complex software with confidence.
Create reusable engineering patterns
Turn successful designs into clear patterns, reference implementations, libraries, and architecture decisions that help teams solve recurring software problems consistently.
Translate architectural risk into clear code-level priorities, decisions, ownership, and sequenced implementation plans. Partner with engineering, product, security, and data teams to move complex software initiatives from design through working code.
You have substantial experience designing, building, operating, and evolving production backend systems, services, APIs, and distributed applications.
You can move from architecture into code, configuration, instrumentation, and diagnosis. Exact experience with Java/Springboot or Golang or Node/Typescript is relevant, but the key here is moving ideas into shippable software solutions and not on the technology.
You can define service boundaries, domain ownership, migration strategies, integration patterns, and practical architecture decisions for complex existing environments.
You can trace difficult behavior through application code, runtime state, database interactions, and dependency flows, then implement fixes that improve correctness, concurrency, performance, and recovery behavior.
You can improve large codebases through domain modeling, modular design, dependency management, incremental refactoring, and carefully chosen abstractions. You know how to create better seams without forcing risky rewrites.
You understand relational databases, SQL behavior, messaging, event consumers, data movement, caching, and the tradeoffs involved in separating applications from legacy data dependencies.
You treat automated testing, code review, static analysis, dependency health, secure coding, and production validation as essential parts of software design—not downstream concerns.
You create clarity across teams, challenge weak assumptions constructively, communicate risk in business terms, and help groups converge on decisions they can execute.
You actively look for ways AI can expand engineering leverage across code comprehension, design exploration, implementation, refactoring, test generation, debugging, documentation, and planning. You help turn promising uses into repeatable practices that make strong engineers more effective.
Critical migrations have clear boundaries, sequencing, ownership, and safety controls. Teams retire legacy constraints while maintaining compatibility and operational continuity.
Codebases have clearer boundaries, stronger tests, healthier dependencies, and fewer hidden couplings. Teams can add capabilities and modernize incrementally without destabilizing unrelated behavior.
Teams understand the target state, the next practical step, and the tradeoffs behind key decisions. Cross-team dependencies and risks are surfaced early and actively managed.
Test coverage, code review, static analysis, dependency health, and production validation become stronger and more consistent across the software in scope.
AI becomes an effective part of how teams understand code, explore designs, implement changes, generate tests, diagnose problems, and document systems.
ABC Fitness depends on critical software and data flows that must evolve without compromising the businesses and members they support. Strong architecture is valuable only when it produces clearer code, better behavior, and software that teams can continue to change.
This role connects long-term technical direction with hands-on software engineering. Done well, it will help teams reduce codebase complexity, modernize with confidence, resolve production problems at their source, and build a stronger foundation for future product development.
Compensation for this role will be determined based on a variety of factors, including relevant experience, qualifications, skills, geographic location, and market considerations. The anticipated compensation range for this position is -
PLN 460,000.00 - 470,000.00- annually. In addition to base compensation, eligible employees may be offered other forms of compensation, such as bonuses, commissions, equity, or other incentive programs, where applicable. Compensation and benefits may vary by location and are subject to applicable legal, business, and market requirements.
At ABC Fitness, we don’t just build technology—we build communities and transform lives. Your work matters here, your growth is supported, and your voice is heard. We welcome diverse talent and encourage you to apply, even if you don’t meet every requirement.
ABC’S COMMITMENT TO DIVERSITY, EQUALITY, BELONGING AND INCLUSION:
ABC is an equal opportunity employer committed to diversity, equity, and inclusion. We strive to create a workplace where every employee, client, and partner feels valued, inspired, and empowered to reach their full potential. For us, inclusion isn’t just the right thing to do—it’s a business imperative. Learn more at abcfitness.com.
ABC Fitness is the #1 software provider for fitness businesses of any size, all around the world. Supporting 30K clubs, 650K coaches, 40M members, and processing more than $12B in payments every year, ABC Fitness provides scalable, data-driven solutions to simplify club management and engage members and clients.
From personal trainers, boutique studios, and gyms, to international franchise health clubs, ABC Fitness will move your business forward through technology and industry insights. Innovation is at the center of everything we do, across ABC Glofox, ABC Ignite, ABC Trainerize, and ABC Evo. Let's make your fitness vision a seamless reality, together. Learn more at abcfitness.com
#LI-REMOTE
With four decades of experience behind us, we’ve brought together a suite of best-in-class platforms and a diverse, global, united team. We are now the only fit tech company on the planet that provides software for any fitness business, of any size, anywhere in the world.
We know you have a passionate vision of fitness you want to offer your clients. We’re here to help you deliver it. Explore our solutions at www.abcfitness.com, and together we'll make things happen.
