Senior Full-Stack Developer

Remote from: Ukraine
Annual salary: Undisclosed
Salary information is not provided for this position. Check our Salary Directory to estimate the average compensation for similar roles.
Department: Software Engineering
Employment type: Full Time,
Job posted: 17 May 2026
Apply before: 17 Jun 2026
Experience level: Senior
Views / Applies: 10 / 3

Crafting Consumer Products of Tomorrow

Actively Hiring

AI Summary

Ruby Labs is seeking a Senior Full-Stack Developer to join their team and help scale a profitable D2C platform used by hundreds of thousands of customers globally. The role involves taking ownership of core product components, collaborating with product teams, mentoring junior developers, and improving engineering standards. Candidates need at least 6 years of full-stack experience, with 2+ years in Next.js, and strong expertise in JavaScript/TypeScript and React. The position is remote within ±4 hours of CET and offers unlimited PTO and paid national holidays. This is a high-ownership, fast-paced role ideal for those excited about building and scaling real products.

Job Complexity

Easy Hard

AI Insight The role requires senior-level expertise with 6+ years of experience, leadership skills, and the ability to work in a high-growth, fast-paced environment. The need for deep technical knowledge across the stack and mentoring responsibilities makes it challenging but not the hardest.

Salary Analysis

AI Insight The salary range is not provided in the listing, but for a Senior Full-Stack Developer role in the US market, the typical range is $120,000 to $200,000 annually. The median is estimated at $150,000. This is competitive for a remote role with unlimited PTO and other benefits.

Key Skills

Next.js React TypeScript PostgreSQL Redis CI/CD Docker AWS Mentoring Full-Stack Development

Cover Letter Sample

Dear Hiring Manager,

I am excited to apply for the Senior Full-Stack Developer position at Ruby Labs. With over 6 years of full-stack development experience and a strong focus on Next.js and React, I am confident in my ability to contribute to scaling your D2C platform. I have a proven track record of taking ownership of core components, mentoring team members, and improving engineering standards in high-growth environments.

In my previous role, I led a team in a continuous deployment environment, implementing CI/CD pipelines and optimizing PostgreSQL and Redis for performance. I thrive in fast-paced settings where I can make data-driven decisions and collaborate closely with product teams. I am particularly drawn to Ruby Labs' mission of creating innovative consumer products and the opportunity to work on a battle-tested platform used by hundreds of thousands of users.

I am eager to bring my technical expertise and leadership skills to your team and help drive the next phase of growth. Thank you for considering my application.

Sincerely,
[Your Name]

Possible Interview Questions

Can you describe a time you took ownership of a core component from concept to deployment? What challenges did you face?

At my previous company, I led the development of a new checkout flow for our e-commerce platform. I worked with product to define requirements, designed the architecture using Next.js and PostgreSQL, and implemented the feature with A/B testing. The main challenge was ensuring the new flow didn't degrade performance under high traffic; I optimized database queries and used Redis caching to maintain speed.

How do you approach mentoring junior developers while maintaining your own productivity?

I schedule regular 1-on-1s and pair programming sessions, focusing on code reviews and knowledge sharing. I also create documentation and encourage juniors to take on small tasks with my guidance. This helps them grow without sacrificing my own output, as I prioritize my work and delegate where appropriate.

Explain your experience with CI/CD pipelines. Can you describe a pipeline you set up or improved?

I set up a GitHub Actions pipeline for a Next.js project that included linting, testing, building, and deploying to AWS ECS. I added automated rollback on failure and integrated with Slack for notifications. This reduced deployment time by 40% and caught errors early.

How would you optimize a PostgreSQL query that is causing performance issues in a high-traffic environment?

First, I would analyze the query using EXPLAIN ANALYZE to identify bottlenecks. I would then consider adding indexes, rewriting the query to reduce joins or subqueries, or using materialized views. If the data is read-heavy, I might introduce Redis caching. I always test changes in a staging environment before deploying.

Describe a situation where you had to make a technical decision and defend it with data. How did you convince the team?

We were deciding between using a monorepo or multiple repos for our microservices. I gathered data on build times, dependency management, and team collaboration. I presented a comparison showing that a monorepo with Nx would reduce build times by 30% and simplify sharing code. I also ran a pilot project to demonstrate the benefits, which convinced the team to adopt it.

About us

Ruby Labs is a leading tech company that creates and operates innovative consumer products. We offer a diverse range of opportunities across the health, education, and entertainment industries. Our innovative teams are driving the future of consumer-led products, and we’re always looking for passionate individuals to join us. Learn more about our story at: https://rubylabs.com/about-us/

About the role

We’re building and scaling a profitable D2C platform used by hundreds of thousands of customers globally, processing large volumes of traffic and revenue every month.

The product is well beyond MVP: it’s battle-tested in production, monetizing at scale, and now entering a phase of rapid growth and expansion. We’ve recently launched a second product in the same ecosystem and are doubling down on building a world-class engineering organization to support continued scale.

We’re looking for a Senior Full-Stack Developer who can combine hands-on technical excellence with strong ownership. You’ll be responsible not just for shipping code, but for shaping architecture, improving reliability, raising engineering standards in a high-paced environment.

This role is not about maintaining a legacy system. It’s about scaling real products used by real users, fast.

If you’re looking for a comfortable 9–5 role, this won’t be the right fit. But if you’re excited by ownership, accountability, and building high-quality systems under real-world pressure, read on.

Key Responsibilities

Take ownership of core product components from concept to deployment.
Collaborate with the Product team to design scalable and maintainable architectures.
Participate in (and lead) code reviews and ensure best practices across the team.
Mentor junior and mid-level developers, providing guidance and fostering growth.
Contribute to hiring and onboarding new team members.
Maintain high code quality and application performance in a fast-paced, high-traffic environment.
Set up and improve CI/CD pipelines and development workflows.
Monitor, debug, and improve the stability and scalability of the system.
Help shape the engineering culture as the team grows.

Qualifications

Core Technical Skills
- At least 6 years of experience of overall full-stack application development.
- At least 2 years of experience with Next.js.
- Strong expertise in JavaScript/TypeScript and modern ReactJS.
- Experience leading a small team in a continuous deployment environment.
- Experience with CI/CD pipelines, Docker, and cloud infrastructure (preferably AWS, Cloudflare).
- Solid understanding of PostgreSQL and Redis, including performance tuning and schema design.
- Experience with A/B testing frameworks and using analytics to drive product decisions.
- Familiarity with CMS (preferably Payload).
Leadership & Collaboration
- Demonstrated ability to mentor other engineers and elevate team performance.
- Clear communication style, able to explain complex topics clearly and concisely.
- A proactive mindset, you spot issues before they become problems and take ownership.
- Comfortable making technical decisions and defending them with logic and data.
- Experience leading teams or projects.

Nice to have

Experience in D2C SaaS products.
Exposure to performance marketing, customer funnel optimization, or rapid MVP cycles.
Contributions to open-source or technical blogs.
Experience working in a fast-paced, high-growth startup environment.

Location

Ruby Labs operates within the CET (Central European Time) zone. Applicants from any country are welcome to apply for the position as long as they are located within approximately ± 4 hours of CET. This ensures optimal collaboration and communication during working hours.

Benefits

Discover the perks of being part of our vibrant team! We offer:

Remote Work Environment: Embrace the freedom to work from anywhere, anytime, promoting a healthy work-life balance.
Unlimited PTO: Enjoy unlimited paid time off to recharge and prioritize your well-being, without counting days.
Paid National Holidays: Celebrate and relax on national holidays with paid time off to unwind and recharge.
Company-provided MacBook: Experience seamless productivity with top-notch Apple MacBooks provided to all employees who need them.
Flexible Independent Contractor Agreement: Unlock the benefits of flexibility, autonomy, and entrepreneurial opportunities. Benefit from tax advantages, networking opportunities, reduced employment obligations, and the freedom to work from anywhere. Read more about it here: https://docs.google.com/document/d/1nkrN76JlZkbKj9WSOhlT1_mni_CZeDkHdwfIjPXVwvk/preview?tab=t.0#heading=h.ndsdl4wapxtt

Be part of our fast-growing team and seize this excellent opportunity for personal and professional growth!

Interview Process

After submitting your application, we conduct a thorough review which typically takes 3 to 5 days, but may occasionally take longer due to the volume of applications received. If we see a potential fit, we proceed with the following steps:

Recruiter Screening (40 minutes)
Technical Interview (90 minutes)
Final Interview (30 minutes)

Life at Ruby Labs

At Ruby Labs, we move fast, aim high, and expect the same from our team. We’re not here to play small—we’re here to build, grow, and win. That means we look for people who are ambitious, driven, and ready to give their best every single day.

This is a place for individuals who thrive under pressure, embrace challenges, and see opportunity in every obstacle. If you’re hungry to achieve, motivated by impact, and want to grow at the speed of your own ambition, Ruby Labs offers the platform to make it happen.

Here, effort is matched with reward. We recognize those who go all in and deliver results, and we create space for people who want more—more responsibility, more growth, and more success.

#LI-Remote

Apply now >