Senior Backend Engineer (Ruby on Rails)

Salve.Lab; Kraków; Remote; PLN 394,000 - 612,000; Full time

Benefits offered by this job

B2B contract

20 working days paid time off annually

Annual in-person gathering

Health and wellbeing support

Learning and development budget

Company laptop and equipment support

Job summary

Salve.Lab is seeking a Senior Backend Engineer specializing in Ruby on Rails to join our R&D and Engineering team. This hands-on role focuses on designing, developing and scaling core backend applications for AI-powered products serving a large international user base.

You will work closely with the CTO, Tech Lead, and SREs, taking ownership of complex features, ensuring performance, reliability and scalability in a fast-paced, fully remote environment across Europe.

Qualifications

• Minimum 5 years of commercial experience as a Backend or Full-Stack Software Engineer.
• Strong, recent hands-on experience developing and maintaining production applications using Ruby on Rails.
• Proven ability to independently design, develop and implement complex backend features.
• Experience working on applications serving thousands or more monthly active users.
• Strong understanding of scalable backend architecture, performance and reliability.
• Experience in startups/scale-ups or fast-paced, agile environments.
• Excellent written and spoken English communication skills.
• Experience collaborating with international, remote teams.
• Based in Europe and able to overlap CET ±3 hours.

Responsibilities

• Design, develop and maintain scalable backend applications using Ruby on Rails.
• Collaborate with Product Managers and engineering stakeholders to translate requirements into technical solutions.
• Develop new features and improve existing functionality.
• Write clean, tested production code and participate in code reviews.
• Troubleshoot issues and improve performance, reliability and scalability.
• Contribute to architectural discussions and product roadmap planning.
• Take ownership of backend features through the full development lifecycle.
• Collaborate with distributed teams to deliver high-quality software.

Skills

Ruby on Rails

Backend development

Code reviews

Communication (English)

Independent ownership

Tools

Git

PostgreSQL

Docker

CI/CD

Job description

About The Role

We are looking for an experienced Senior Backend Engineer specialising in Ruby on Rails to join the R&D and Engineering team of a fast-growing AI technology company serving millions of users worldwide. In this hands-on individual contributor role, you will be responsible for designing, developing and scaling core backend applications that support innovative AI-powered products. Working closely with the CTO, Tech Lead, Product Managers and Site Reliability Engineers, you will contribute to technical decisions, improve application performance and deliver reliable, scalable software solutions. This opportunity is ideal for an experienced engineer who enjoys taking ownership of complex technical challenges, working in agile environments and contributing directly to product development.

Key Responsibilities

• Design, develop and maintain scalable backend applications using Ruby on Rails.
• Collaborate with Product Managers and engineering stakeholders to analyse requirements and translate product specifications into technical solutions.
• Prepare technical integration plans, development breakdowns and accurate effort estimates.
• Develop new features and continuously improve existing application functionality.
• Write clean, efficient, maintainable and well-tested production code.
• Participate in pull requests, peer code reviews and software testing to maintain high engineering standards.
• Troubleshoot application issues and implement improvements to performance, reliability and scalability.
• Contribute to architectural discussions, technical decision-making and product roadmap planning.
• Take ownership of complex backend features throughout the complete development lifecycle, from initial requirements to production deployment.
• Identify and resolve technical bottlenecks, ensuring applications remain stable as user demand grows.
• Explore new technologies, frameworks and development approaches to improve product functionality and user experience.
• Collaborate with distributed engineering, infrastructure, SRE and product teams to deliver high-quality software.
• Contribute to continuous improvement initiatives across development processes, code quality and system architecture.

Requirements

• Minimum 5 years of commercial experience as a Backend or Full-Stack Software Engineer.
• Strong, recent hands-on experience developing and maintaining production applications using Ruby on Rails.
• Proven ability to independently design, develop and implement complex backend features.
• Experience working on applications serving thousands or more monthly active users.
• Strong understanding of scalable backend architecture, application performance and system reliability.
• Demonstrated experience delivering features throughout the full software development lifecycle, including requirements analysis, implementation, testing and production deployment.
• Experience working in technology startups, scale-ups or similarly fast-paced, agile engineering environments.
• Ability to adapt to changing priorities, manage deadlines and maintain high engineering standards.
• Solid understanding of software engineering principles, clean code practices and automated testing.
• Experience participating in code reviews and collaborating with cross-functional development teams.
• Strong analytical thinking, troubleshooting skills and a proactive approach to technical problem-solving.
• Ability to work independently, take ownership of technical deliverables and contribute to engineering decisions.
• Excellent written and spoken English communication skills.
• Experience collaborating effectively with international, fully remote teams.
• Must be based in Europe and available to work with CET ±3 hours overlap.

Benefits

• Fully remote working arrangement from anywhere in Europe.
• B2B contract.
• 20 working days of paid time off annually.
• Annual in-person company gathering.
• Health and wellbeing support.
• Dedicated learning and professional development budget.
• Company laptop and equipment support.
• Access to premium AI development tools, including Cursor, Claude Code and ChatGPT.
• Direct collaboration with experienced engineering leadership, including the CTO and Tech Lead.
• Opportunity to influence technical decisions and contribute to the evolution of core product architecture.
• Hands-on involvement in innovative AI-powered products serving a large international user base.
• Autonomy and ownership within a fast-growing engineering environment.
• Additional benefits and professional development opportunities.