Senior / Lead Ruby on Rails Developer

🏢 Summary: The offer is for a Ruby on Rails Developer to build and maintain modern web applications for a new project, contributing to scalable solutions and microservices architecture. The role involves working with Ruby on Rails as the core technology, with exposure to Node.js and React, in a collaborative and agile environment. 🗂️ Requirements: Proven commercial experience with Ruby on Rails, Experience building modern web applications, Experience with Node.js and/or React, Understanding of microservices architecture, Ability to participate in code reviews and follow coding standards, Very good English skills 📃 Skills: Ruby, Rails, Node.js, React, Microservices, REST, Git 🏢 Description: We are seeking a skilled Ruby on Rails Developer to join our team for an exciting new project. Responsibilities Develop and maintain web applications using Ruby on Rails as the primary technology. Collaborate with cross-functional teams to design and implement scalable solutions. Contribute to the architecture and development of microservices, where applicable. Utilize Node.js and React technologies to enhance application features and performance. Participate in code reviews and ensure adherence to best practices and coding standards. Communicate effectively with stakeholders to understand project requirements and deliver solutions accordingly. Qualifications Proven commercial experience in Ruby on Rails development. Experience working with modern web applications and frameworks. Exposure to Node.js and/or React technologies. Understanding of microservices architecture is preferred. Strong problem-solving skills and ability to work collaboratively within a team setting. Very good English level. Benefits Opportunity to participate in a cutting-edge project with a dynamic and innovative team. Professional growth through engagement in technical interviews and project development phases. Remote work (Poland). Exposure to a diverse technology stack including Ruby on Rails, Node.js, React, and microservices. Unique TEAL culture, relationship- and respect-driven community, non-corporate atmosphere. Agile approach and no bureaucracy. Outstanding integration trips to various places in Europe for all employees. Activities to support your well-being and health. Luxmed Gold Extended medical care and Multisport Plus benefit.

🏢 Summary: Senior individual contributor engineering role focused on building and delivering scalable software, driving technical direction, solving complex problems, and mentoring engineers while remaining hands-on with development. The position involves working across backend and frontend systems using Ruby, Rails, React, PostgreSQL, Redis, Kafka, Elasticsearch, and Kubernetes. 🗂️ Requirements: Strong experience with Ruby, Experience leading complex cross-team projects, Ability to solve complex technical problems, Ability to work independently in ambiguous environments, Strong communication with technical and non-technical stakeholders, Experience mentoring engineers 📃 Skills: Ruby, Rails, PostgreSQL, Redis, React, Kafka, Elasticsearch, Kubernetes 🏢 Description: We are looking for a Senior Engineer to join our team and help us build and deliver software at scale. We have a flat structure, but this is a very senior individual role for someone who can make a big impact. In this role, you will take initiative, solve complex problems, improve our technical standards, and support other engineers. You will work closely with leadership to shape our technical direction while still writing code. Our Tech Stack Ruby 3.3.8 & Rails 7.2 PostgreSQL & Redis React (frontend) Kafka, Elasticsearch, Kubernetes (K8s) What you will do Drive technical work: Help turn high-level goals into clear projects and plans. Support the team: Mentor both junior and senior engineers to help them grow. Set standards: Improve how we work and make sure our code stays maintainable in the future. Handle uncertainty: Work without clear instructions at times, set direction, and guide others. Solve complex problems: Take the lead on difficult issues and important technical decisions. What we are looking for Strong experience with Ruby Experience in HR, Fintech, or Accounting systems is a plus Proven impact: experience leading complex projects across teams Good communication: able to work with both engineers and non-technical stakeholders Initiative: able to find important problems and follow through with solutions The process Screening call: 15-minute chat with a recruiter System design interview: 60-minute discussion about architecture Behavioral interview: 60-minute conversation about your experience and teamwork Final call: conversation with the CEO

🏢 Summary: Senior individual contributor role focused on building and delivering scalable software systems while shaping technical direction and standards. The position combines hands-on Ruby/Rails development with system design, cross-team technical leadership, and mentoring. The engineer will lead complex initiatives and drive architectural decisions in a modern distributed stack. 🗂️ Requirements: Strong experience with Ruby, Experience with Rails framework, Experience designing scalable systems, Proven experience leading complex cross-team technical projects, Ability to make architectural decisions, Experience mentoring engineers, Experience with distributed systems and backend integrations, Ability to work with PostgreSQL and Redis, Experience working with React frontend, Experience with Kafka, Elasticsearch, and Kubernetes 📃 Skills: Ruby, Rails, PostgreSQL, Redis, React, Kafka, Elasticsearch, Kubernetes, HR, Fintech, Accounting 🏢 Description: We are looking for a Senior Engineer to join our team and help us build and deliver software at scale. We have a flat structure, but this is a very senior individual role for someone who can make a big impact. In this role, you will take initiative, solve complex problems, improve our technical standards, and support other engineers. You will work closely with leadership to shape our technical direction while still writing code. Our Tech Stack Ruby 3.3.8 & Rails 7.2 PostgreSQL & Redis React (frontend) Kafka, Elasticsearch, Kubernetes (K8s) What you will do Drive technical work: Help turn high-level goals into clear projects and plans. Support the team: Mentor both junior and senior engineers to help them grow. Set standards: Improve how we work and make sure our code stays maintainable in the future. Handle uncertainty: Work without clear instructions at times, set direction, and guide others. Solve complex problems: Take the lead on difficult issues and important technical decisions. What we are looking for Strong experience with Ruby Experience in HR, Fintech, or Accounting systems is a plus Proven impact: experience leading complex projects across teams Good communication: able to work with both engineers and non-technical stakeholders Initiative: able to find important problems and follow through with solutions The process Screening call: 15-minute chat with a recruiter System design interview: 60-minute discussion about architecture Behavioral interview: 60-minute conversation about your experience and teamwork Final call: conversation with the CEO

🏢 Summary: Freelance Principal Software Developer role focused on leading and architecting Ruby on Rails and React-based admin panels and internal tools, with full ownership of technical direction and quality. The position emphasizes senior-level decision-making, end-to-end responsibility, and building maintainable systems in smaller-scale environments. Strong focus on robust testing and long-term system evolution. 🗂️ Requirements: 8+ years of software development experience, Senior-level expertise in Ruby on Rails, Senior-level expertise in React, Proven experience defining architecture and technical direction, Experience designing and maintaining robust test suites, Experience building admin panels and internal tools, Ability to work independently and take end-to-end ownership, Experience translating stakeholder needs into technical solutions 📃 Skills: Ruby, Rails, React, JavaScript, Testing, Architecture 🏢 Description: We’re specifically looking for a Principal Software Developer (Ruby on Rails & React) - Freelancer What We’re Looking For A Full-Stack Craftsman: You are an expert in Ruby on Rails and TypeScript , capable of building everything from complex dashboards and billing UIs to sleek documentation platforms. The "DevEx" Champion: You have a natural empathy for other developers. You’ll develop deep knowledge of our platform (Pub/Sub, Chat, LiveSync) and use the product yourself to gain a first-hand understanding of the developer experience. Comfortable with Ambiguity: You thrive in high-level vagueness. You can take a feature from a loose concept to a shipped product with minimal hand-holding, identifying problems and proposing solutions independently rather than waiting for a roadmap. Accountable & Reliable: You take pride in high-quality, well-tested code. You meet your delivery commitments, provide realistic estimates based on technical complexity, and communicate proactively if a timeline is ever at risk. An Owner: You monitor what you build in production and take personal ownership of quality issues. You see a feature through its entire lifecycle, from the first line of code to the final metric. What do we mean by freelance? Read more at Monterail Tech Network

🏢 Summary: Freelance Principal Software Developer role focused on leading architecture and development of internal tools and admin panels using Ruby on Rails and React. The position requires strong end-to-end ownership, technical direction, and responsibility for system quality and evolution. You will design robust solutions, maintain comprehensive test suites, and collaborate closely with internal stakeholders. 🗂️ Requirements: 8+ years of software development experience, Senior-level expertise in Ruby on Rails, Senior-level expertise in React, Experience defining architecture and making technical decisions, Experience designing and maintaining robust test suites, Experience building admin panels and internal tools, Ability to translate stakeholder needs into technical solutions, Experience working in small-scale or internal environments, Ability to work independently and take technical ownership 📃 Skills: Ruby, Rails, React, JavaScript, Testing, Architecture 🏢 Description: We’re specifically looking for a Principal Software Developer (Ruby on Rails & React) - Freelancer What We’re Looking For A Full-Stack Craftsman: You are an expert in Ruby on Rails and TypeScript , capable of building everything from complex dashboards and billing UIs to sleek documentation platforms. The "DevEx" Champion: You have a natural empathy for other developers. You’ll develop deep knowledge of our platform (Pub/Sub, Chat, LiveSync) and use the product yourself to gain a first-hand understanding of the developer experience. Comfortable with Ambiguity: You thrive in high-level vagueness. You can take a feature from a loose concept to a shipped product with minimal hand-holding, identifying problems and proposing solutions independently rather than waiting for a roadmap. Accountable & Reliable: You take pride in high-quality, well-tested code. You meet your delivery commitments, provide realistic estimates based on technical complexity, and communicate proactively if a timeline is ever at risk. An Owner: You monitor what you build in production and take personal ownership of quality issues. You see a feature through its entire lifecycle, from the first line of code to the final metric. What do we mean by freelance? Read more at Monterail Tech Network

🏢 Summary: Senior Ruby on Rails Developer role focused on building and evolving a cloud-ready product into a scalable, distributed system. The position involves designing architecture, developing core services and APIs, and driving Kubernetes-based deployments with CI/CD automation. You will influence engineering standards and contribute production-ready code in a greenfield development environment. 🗂️ Requirements: 5+ years of software engineering experience, Senior-level Ruby on Rails expertise, Experience building and scaling distributed systems, Knowledge of Kubernetes, Experience with CI/CD pipelines, Experience with Infrastructure as Code, Strong API design skills, Experience with microservices communication, Ability to lead architectural initiatives, Mentoring experience for engineers 📃 Skills: Ruby, Rails, Kubernetes, CI/CD, IaC, API, Microservices, DistributedSystems 🏢 Description: We are looking for an experienced Senior Ruby on Rails Developer to join the team responsible for development of the product, which is evolving into a modern, cloud‑ready solution. In this role, you will have opportunity to influence architectural decisions, contribute production‑ready code, and collaborate closely with cross‑functional teams. Your daily responsibilities: Build and improve core platform services and APIs Design scalable, distributed system architecture Implement and optimize key components in the codebase Set engineering standards for reliability and maintainability Drive deployments using Kubernetes and CI/CD automation Collaborate across teams to align technical and product goals. Requirements: 5+ years of software engineering experience, including senior‑level work Strong proficiency in Ruby on Rails Experience building and scaling distributed systems Solid knowledge of Kubernetes, CI/CD, and IaC Strong skills in API design and microservice communication Ability to lead architectural initiatives and mentor other engineers. What we offer: Attractive salary and benefits package, including Multisport card, insurance, and medical care Hybrid work from the Krakow office International work environment in a product company Training and development opportunities within the organization Joining the greefield project with pure development. Apply now!

🏢 Summary: Full-Stack Developer (Ruby on Rails) role within an R&D team building advanced life science research platforms. The position involves designing and delivering scalable, secure web solutions across frontend and backend, contributing to architecture and product direction. The engineer will work in an agile environment to enhance a multi-tenant SaaS platform used globally by researchers. 🗂️ Requirements: Minimum 3 years of professional web development experience, Strong hands-on experience with Ruby on Rails, Solid backend and frontend development knowledge, Experience with HTML, CSS, and JavaScript, Experience building and maintaining APIs, Experience with AWS and CI/CD pipelines, Proficiency with Git, Experience with AI-assisted development tools, Ability to develop scalable and secure applications 📃 Skills: Ruby, Rails, HTML, CSS, JavaScript, Hotwire, React, AWS, CI/CD, Git, Docker, MySQL, Elasticsearch, APIs 🏢 Description: For one of our clients, we are currently seeking an experienced Full‑Stack Developer (Ruby on Rails) to join an R&D team building advanced platforms for life science research. This role is ideal for an engineer who values clean architecture, high‑quality code, and modern web development practices. You will become part of an agile, highly motivated engineering team responsible for building and evolving a platform used daily by researchers and laboratories worldwide. As an experienced engineer, you will play a meaningful role in shaping the technical direction of the product and driving future platform improvements. Working closely with product leaders and management, you will ensure that our solutions continue to meet the needs of a growing scientific community. What You Will Do Design, implement, and ship new features as well as future releases of the platform across frontend and backend layers. Build, improve, and maintain robust platform APIs with a strong focus on scalability, reliability, and performance. Write clear, maintainable, and well‑tested code, following iterative and test‑driven development principles. Collaborate closely with product and management teams to transform business requirements into effective technical solutions. Help develop a highly scalable service deployed in multi‑tenant SaaS, single‑tenant SaaS, and on‑premise environments. Apply secure development practices and contribute to system scalability and performance optimization. Actively use AI‑assisted development tools to speed up coding, reviews, and testing workflows. Contribute positively to team collaboration, sharing ownership and fostering a supportive and enjoyable work culture. Experience & Technical Requirements Required: Minimum of 3 years of professional experience in web development, with solid knowledge of both backend and frontend development. Required: Strong, hands‑on experience with Ruby on Rails . Experience with several of the following technologies: HTML, CSS, JavaScript, Hotwire, React, AWS, CI/CD pipelines, Git . Experience with Docker is considered an advantage. Experience with MySQL is a plus. Experience with Elasticsearch is a plus. Hands‑on use of AI‑powered tools to accelerate development (e.g. AI‑assisted coding, automated code reviews, or testing). Experience integrating AI workflows into the software development lifecycle is considered a nice‑to‑have. Who You Are A collaborative team member who raises the technical bar and encourages excellence in others. Comfortable explaining ideas, designs, and decisions to both technical and non‑technical stakeholders. Able to thrive in a fast‑paced, agile environment where results are delivered in short cycles. Opinionated about technology choices and how to apply them effectively to deliver real value to users and the business. A pragmatic yet passionate polyglot programmer with a strong software engineering foundation. Open to experimenting with and adopting AI tools as part of everyday development work. Willing to work from the office at least two days per week, with flexibility to work remotely when needed. A background or degree in Life Sciences is a significant advantage. Hays Poland sp. z o.o. jest agencją zatrudnienia zarejestrowaną w rejestrze prowadzonym przez Marszałka Województwa Mazowieckiego pod numerem 361.

🏢 Summary: Backend Engineer role focused on building and maintaining high-volume, complex API integrations using pure Ruby in a transactional, money-flow–critical domain. The position involves designing robust backend services, ensuring reliability and transactional integrity, and collaborating with stakeholders and external partners. The environment emphasizes AWS-based infrastructure, DevOps practices, and secure, scalable solutions. 🗂️ Requirements: Strong experience with Ruby (beyond Ruby on Rails), Proven experience delivering backend services in complex domains, Expertise in API design and third-party integrations, Familiarity with transactional systems and reliability constraints, Solid understanding of DevOps practices, Experience with Infrastructure-as-Code, Hands-on experience with AWS (EC2, S3, RDS), Experience with Docker, Experience with Redis, Strong analytical skills, Clear stakeholder communication skills 📃 Skills: Ruby, Redis, Docker, AWS, EC2, S3, RDS, Infrastructure-as-Code, API, Thin, EventMachine, Sinatra, Elasticsearch 🏢 Description: Project overview This project focuses on building and maintaining high-volume, complex API integrations with external partners in a domain where transactional integrity and money flows are critical. Position overview We are looking for a Backend Engineer with strong expertise in pure Ruby. In this role, you will design and maintain robust backend services and high-volume API integrations in a domain where transactional integrity and money flows are critical. You’ll collaborate closely with stakeholders and external partners to deliver secure, scalable solutions. Technology stack Ruby (pure Ruby, not Rails-centric) Redis Docker AWS services (EC2, S3, RDS) Infrastructure-as-Code tools Responsibilities Design and implement robust backend services using Ruby Develop and maintain complex API integrations with external systems Ensure transactional integrity and reliability in high-volume environments Collaborate with stakeholders and external partners to clarify requirements Contribute to infrastructure automation and deployment processes Participate in technical design discussions and solution shaping Requirements Strong experience with Ruby (beyond Ruby on Rails) Proven track record of delivering backend services in complex domains Expertise in API design, integration, and third-party connectivity Familiarity with transactional systems and reliability constraints Solid understanding of DevOps practices and Infrastructure-as-Code Hands-on experience with AWS services (EC2, S3, RDS) Knowledge of Docker for containerization Experience with Redis Strong analytical skills for navigating intricate business rules Clear and confident communication skills for stakeholder engagement Nice to have Thin, EventMachine, Sinatra Exposure to Elasticsearch. Experience in financial or transactional domains. What We Offer: Vacation days : Up to 26 business days per year. 10 illness/special days off per year (fully paid, no medical papers needed) for all contract types Health and life insurance (Luxmed) MyBenefit platform with Multisport option Internal psychological support service English language classes from the first working day Access to external learning platforms : O’Reilly, LinkedIn Learning, Udemy, and a wide catalog of diverse internal training Flexible workplace : work from the office, from home, or choose a hybrid option Tech Skills Mentoring Program Opportunities to develop as a public speaker, mentor, or technical interviewer Fully paid idle (bench) when not involved in a project Certification reimbursement (AWS, GCP, Microsoft, etc.)

🏢 Summary: Senior Software Engineer role focused on developing and scaling a robust platform using Ruby on Rails, with responsibility for building secure services and APIs. The position involves implementing new features, improving system performance, and supporting integrations with external partners. This hybrid role in Warsaw includes technical ownership of developed services and participation in agile processes. 🗂️ Requirements: Minimum 5 years of professional Software Engineering experience, Strong proficiency in Ruby on Rails, Experience with React and component-based frameworks, Working knowledge of JavaScript or TypeScript, Experience developing and managing APIs, Ability to work in a hybrid (office/remote) model, Advanced written and spoken English 📃 Skills: Ruby, Rails, React, JavaScript, TypeScript, GraphQL, APIs, Agile 🏢 Description: Our Client, an American software company is opening a new branch in Warsaw and we are looking for a Senior Software Engineer with Ruby to join a growing team. About the Position This role focuses on enhancing and maintaining a robust platform, supporting new project initiatives, and delivering scalable solutions that improve the user experience for both industry professionals and individual clients. The ideal candidate is proactive, collaborative, and committed to delivering high-quality, scalable software. This is a hybrid role based in Warsaw, Poland. Key Responsibilities Design and implement new functionalities for a cutting-edge platform Develop and manage APIs to enable smooth integration with financial and sales partners Build secure and scalable services designed for sustained performance Support agile development practices and help ensure consistent, impactful sprint results Mentor team members and contribute to a positive engineering culture through knowledge-sharing Maintain and take responsibility for services you develop, including participating in the on-call rotation Requirements Minimum 5 years of professional experience as a Software Engineer Strong proficiency with Ruby on Rails Excellent communication skills and experience working in cross-functional teams Familiarity with React and component-based front-end frameworks Working knowledge of JavaScript and/or TypeScript Ability to perform in a hybrid (office/remote) work environment Advanced written and spoken English (please provide your CV in English) Nice to have Experience with GraphQL

🏢 Summary: Lead Frontend Developer role focused on building and improving modern web applications while setting technical direction and leading a development team. The position involves designing intuitive interfaces, integrating with backend systems, and driving best practices in code quality and CI/CD processes. 🗂️ Requirements: 5+ years of experience with JavaScript, Experience leading development teams, Proficiency with Angular, Experience with Node.js, Experience with Hibernate and Oracle DB, Strong knowledge of SQL, Experience with Cucumber, Experience with IntelliJ, Experience with Splunk and JMeter, Experience with Git, Jenkins, and Maven, Experience integrating CI/CD pipelines, Understanding of SOLID principles 📃 Skills: JavaScript, Angular, Node.js, Hibernate, Oracle, SQL, Cucumber, IntelliJ, Splunk, JMeter, Git, Jenkins, Maven, CI/CD, SOLID 🏢 Description: Currently, we are looking for a Lead Frontend Developer , who has proven experience developing web applications using all front-end technologies. Responsibilities: Creating new, better and more functional, and intuitive interfaces for services Helping to set technical direction, realizing your ideas in code, and collaborating with other developers, teams, and stakeholders Inventing and improving services and processes Required skills and qualifications: Experience in leading the team. The Lead Frontend must know how to build a productive team to deliver a brighter future At least 5 + years experience in developing software using JavaScript Fluency working with Angular, Node.js, Hibernate, Oracle DB, SQL, Cucumber, IntelliJ, Splunk, JMeter Experience integrating codebase with CI/CD processes using Git, Jenkins, Maven Strong communication, organizational, team and time-management skills Proficient understanding and knowledge of SOLID principles Fluent in English, written and spoken Nice to have: General understanding of Java programming language Experience with prepared and executed various tests: automation, performance, unit, integration We offer: Fully remote work- not only during the pandemic - related restrictions Long-term cooperation based on b2b contact or an employment contract The possibility of developing your competencies, working in new technologies and creating an innovative system from the very beginning Work in an international environment - the possibility of using English in everyday work A wide package of benefits (private healthcare, life insurance, sport card, free English lessons, internal trainings and workshops, external trainings, integration events)