Senior Backend Engineer

Remote from: Europe
Annual salary: Undisclosed
Salary information is not provided for this position. Check our Salary Directory to estimate the average compensation for similar roles.
Department: Programming
Employment type: Full Time,
Job posted: 11 Jun 2026
Apply before: 11 Jul 2026
Experience level: Senior
Views / Applies: 11 / 2

Crafting Consumer Products of Tomorrow

Actively Hiring

AI Summary

Ruby Labs is seeking a Senior Backend Engineer to design, build, and scale backend systems for their AI product. The role requires deep expertise in distributed systems, Node.js, AWS, and observability tools like Sentry and OpenTelemetry. It offers high ownership and collaboration within a remote team operating near CET timezone. Benefits include unlimited PTO and a company-provided MacBook. Ideal candidates are passionate about infrastructure and have startup experience.

Role DNA

Job Complexity

Easy Hard

Pace & Pressure

Relaxed Fast-paced

Autonomy Level

Guided Full Ownership

Communication Load

Independent Highly Collaborative

AI Insight The role demands deep expertise in distributed systems, Node.js, AWS, and observability, which are complex and require significant experience. The high ownership and production debugging raise the difficulty level to 4.

Salary Analysis

AI Insight The salary range was not provided. For a Senior Backend Engineer in the US market, the typical range is $120k-$200k, with a median around $160k. Given the high ownership and technical requirements, the offered salary should be competitive within this range.

Key Skills

Node.js AWS Distributed Systems Redis Cloudflare OpenTelemetry Sentry Backend Architecture System Design Observability

Cover Letter Sample

Dear Hiring Team at Ruby Labs,

I am writing to express my strong interest in the Senior Backend Engineer role. With over 5 years of experience in designing scalable distributed systems and deep expertise in Node.js and AWS, I am excited about the opportunity to contribute to your innovative AI products. My background includes building resilient backend services, implementing observability with OpenTelemetry and Sentry, and leading incident investigations in fast-paced environments.

I particularly value the high-ownership culture described, as I thrive in roles where I can drive both feature delivery and infrastructure excellence. My experience with Redis, Cloudflare Workers, and performance tuning aligns well with your tech stack. I am also comfortable working in a remote, collaborative team within CET timezone.

Thank you for considering my application. I look forward to the possibility of discussing how I can contribute to Ruby Labs' continued success.

Sincerely,
[Your Name]

Possible Interview Questions

Describe your experience designing and scaling a distributed system. What challenges did you face and how did you overcome them?

At my previous company, I designed a microservices architecture for a real-time analytics platform. We used Node.js and AWS Lambda, with Redis for caching and Pub/Sub. Challenges included data consistency and latency. We implemented event sourcing and used DynamoDB streams to ensure eventual consistency. Monitoring with OpenTelemetry helped us trace issues and optimize performance.

How do you approach debugging a production issue in a distributed system? Give a specific example.

I start by gathering logs, metrics, and traces from our observability tools. For instance, we had a spike in API errors. I used Sentry to identify the error pattern and OpenTelemetry traces to find a slow database query. It turned out a missing index on a large table caused timeouts. I added the index and implemented query optimization, then monitored to confirm resolution.

Explain your experience with Redis beyond basic caching. How have you used Redis for pub/sub, queues, or other features?

I've used Redis extensively: for session stores with cluster mode, pub/sub for real-time notifications, and Redis streams for job queues. In one project, I used Redis to implement a rate limiter using sorted sets, and also used Lua scripting for atomic operations. I'm experienced with replication and persistence to ensure data durability.

How do you ensure code quality and maintainability in a fast-paced environment?

I advocate for SOLID principles, write unit and integration tests, and conduct thorough code reviews. I also focus on clean architecture and documentation. In a fast-paced environment, I prioritize technical debt reduction and refactoring to maintain velocity. I use linters and static analysis to catch issues early.

Describe a time you had to collaborate closely with a cross-functional team to deliver a complex feature. How did you handle communication and ownership?

I worked with frontend and product teams to launch a real-time collaboration feature. We had daily stand-ups and used shared documentation. I owned the backend architecture, but I ensured alignment by discussing trade-offs openly. When we faced a scalability issue, I proposed a solution and worked with the team to implement it quickly. The feature shipped on time.

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

At RubyLabs we’re hiring a Senior Backend Engineer to help design, build, and scale the core backend systems that power our AI product. This is a high-ownership role for an engineer who loves solving distributed systems challenges and driving both feature delivery and infrastructure excellence. This position requires close collaboration with our development team to ensure consistency, quality, and alignment across all projects.

Key Responsibilities

Deliver new backend features with a focus on scalability, performance, and reliability.
Maintain, optimize, and improve existing services and infrastructure.
Design, deploy, and operate backend services across AWS, Cloudflare, and other environments.
Implement and evolve monitoring and observability using tools such as Sentry, OpenTelemetry (OTel), logging, alerting, and related platforms.
Investigate and resolve production issues across distributed systems.
Write clean, maintainable code aligned with SOLID principles, system design, and backend best practices.
Lead incident investigations, root cause analysis, and system reliability improvements.
Contribute to architectural decisions, documentation, and infrastructure planning.
Collaborate with high standards for communication, ownership, and delivery.

Qualifications

Deep expertise in distributed systems, system design, and backend architecture.
Strong understanding of database fundamentals, indexing, consistency, replication, transactions, and storage trade-offs.
Proven ability to design scalable and resilient systems.
Fluency in Node.js backend development.
Strong grasp of software engineering principles, including SOLID.
Experience debugging complex issues in production environments.
Experience with cloud infrastructure (AWS) and backend service deployment.
Experience implementing monitoring and observability using tools such as Sentry and OpenTelemetry (OTel), including tracing, logging, and alerting.
High standards for code quality, reliability, and communication.
Deep knowledge of Redis, including caching, pub/sub, queues, replication, persistence, and performance tuning.
Strong experience with AWS services, including compute, serverless, networking, storage, security, and infrastructure-as-code.
Experience with Cloudflare Workers, edge routing, caching, and security primitives.
Familiarity with Sentry performance monitoring and OpenTelemetry instrumentation at scale.
Comfortable working in timezone ±2 hours from UK time.

Nice to have

Experience working in startup environments or small, high-autonomy engineering teams.
Passion for building and improving infrastructure, developer experience, and observability.

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)
First Interview (30 minutes)
Technical Interview (45 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

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