Software Engineer (Python OR Ruby on Rails)

🏢 Summary: Senior Software Engineer role focused on building and maintaining scalable Ruby on Rails solutions for a clean-energy platform used by solar professionals. The position involves developing backend services and APIs, collaborating across teams, mentoring engineers, and contributing to high-quality product delivery in a hybrid work environment. 🗂️ Requirements: 5+ years of professional software engineering experience, Strong proficiency in Ruby on Rails, Experience with React, Knowledge of JavaScript, Knowledge of TypeScript, Clear communication skills, Ability to work in a distributed remote environment, Strong English communication skills 📃 Skills: Ruby, Rails, React, JavaScript, TypeScript, GraphQL, APIs 🏢 Description: Senior Software Engineer (Ruby on Rails) Salary: 19,000-28,000 PLN Hybrid (2 days on site) Full-time Contract through Deel We’re looking for a Senior Software Engineer for a leading software provider in the clean-energy space, building technology that helps solar professionals design and sell solar projects accurately and at scale. Their platform has powered millions of solar designs and is recognized as one of the top remote-friendly and sustainability-focused companies in the industry. Requirements: - 5+ years of professional software engineering experience - Strong proficiency with Ruby on Rails - Clear communication skills and comfort working cross-functionally - Familiarity with React and component-based frontend development - Working knowledge of JavaScript and/or TypeScript - Ability to thrive in a fully remote, distributed environment - Strong English skills (written and spoken) Nice to Have: - Experience with GraphQL - Interest in renewable energy, climate tech, or mission-driven products Responsibilities: - Build new features for a leading platform used by solar professionals for design and sales - Design and maintain reliable APIs that integrate smoothly with financial and sales partners - Develop secure, scalable backend services built for long-term stability and performance - Contribute to agile planning and help drive predictable, high-quality delivery - Mentor teammates, share knowledge, and strengthen the overall engineering culture - Take ownership of the services you build, including participating in on-call rotations Benefits: - Health Coverage: Medical, dental, and vision insurance - Internet & Mobile Stipend - Work-From-Home Support (home office budget) - Learning & Development support

🏢 Summary: Full-time Senior Software Engineer role focused on building and scaling a Ruby on Rails-based platform used by solar professionals to design and sell solar projects. The position involves developing secure, high-performance backend services, reliable APIs, and contributing to frontend features in a distributed, hybrid work environment. The engineer will also support agile delivery, system ownership, and technical mentorship. 🗂️ Requirements: 5+ years of professional software engineering experience, Strong proficiency in Ruby on Rails, Experience with React and component-based frontend development, Working knowledge of JavaScript or TypeScript, Experience designing and maintaining APIs, Experience building secure, scalable backend systems, Ability to work in distributed, remote environment, Strong English communication skills 📃 Skills: Ruby, Rails, React, JavaScript, TypeScript, GraphQL, API, Backend, Agile 🏢 Description: Senior Software Engineer (Ruby on Rails) 💰 Salary: 19,000-28,000 PLN 🌎 Hybrid (2 days on site) ☑️ Full-time 🕦 Contract through Deel We’re looking for a Senior Software Engineer for a leading software provider in the clean-energy space, building technology that helps solar professionals design and sell solar projects accurately and at scale. Their platform has powered millions of solar designs and is recognized as one of the top remote-friendly and sustainability-focused companies in the industry. Requirements: 5+ years of professional software engineering experience. Strong proficiency with Ruby on Rails. Clear communication skills and comfort working cross-functionally. Familiarity with React and component-based frontend development. Working knowledge of JavaScript and/or TypeScript. Ability to thrive in a fully remote, distributed environment. Strong English skills (written and spoken). Nice to Have Experience with GraphQL . Interest in renewable energy, climate tech, or mission-driven products. Responsibilities: Build new features for a leading platform used by solar professionals for design and sales. Design and maintain reliable APIs that integrate smoothly with financial and sales partners. Develop secure, scalable backend services built for long-term stability and performance. Contribute to agile planning and help drive predictable, high-quality delivery. Mentor teammates, share knowledge, and strengthen the overall engineering culture. Take ownership of the services you build, including participating in on-call rotations. Benefits Health Coverage: Medical, dental, and vision insurance Internet & Mobile Stipend Work-From-Home Support (home office budget) Learning & Development support

🏢 Summary: Full-time hybrid Software Engineer role focused on building responsive, AI-driven web applications for enterprise platforms using modern JavaScript technologies. The position involves developing high-quality React-based interfaces, applying TDD and CI practices, and collaborating within cross-functional Agile teams. Long-term B2B contract based in Warsaw with competitive salary. 🗂️ Requirements: 6+ years experience with JavaScript, 6+ years experience with TypeScript, Strong knowledge of design patterns in JavaScript, Proficiency in React with Redux, Experience with Next.js, Understanding of functional programming concepts, Strong knowledge of asynchronous programming, Experience with Git and branch management, Experience debugging front-end applications, Experience creating and integrating custom packages, Understanding of object-oriented programming principles, Practical experience with HTML5, Practical experience with CSS3, Experience in Agile environments, Ability to develop cross-browser compatible code 📃 Skills: JavaScript, TypeScript, React, Redux, Next.js, HTML5, CSS3, Git, TDD, CI, Agile 🏢 Description: 💰 Salary: 14,500-17,000 PLN/month 🌎 Hybrid from Warsaw, Poland 🕦 Full-time position, long-term ☑️ B2B We are looking for a Software Engineer to join our client, a technology company that builds AI-powered platforms and consulting solutions for enterprise operations, with a strong focus on the private capital sector. The company has over ten years of experience working with high-growth and PE-backed businesses, combining deep domain expertise with advanced technology to drive measurable results. Requirements: 6+ years of experience working with JavaScript and TypeScript Solid understanding of design patterns and how to apply them in JavaScript development. Proficiency in a modern front-end JavaScript framework such as React.js with Redux; experience with Next.js is an advantage. Familiarity with functional programming concepts. Strong grasp of asynchronous programming and its best practices. Knowledge of Git and experience with branch management. Experience troubleshooting front-end issues and using relevant debugging tools. Familiarity with creating and integrating custom packages. Good understanding of object-oriented programming principles and their use in JavaScript. Ability to perform effectively under pressure and meet strict deadlines. Practical experience with HTML5 and CSS3. Experience working within Agile development environments and practices. Strong communication and organizational abilities. Skilled in developing cross-browser compatible code. A Bachelor’s degree in Computer Science or a related field is preferred. Key Responsibilities: Creating and building responsive user interfaces using React. Applying and maintaining test-driven development (TDD) practices along with continuous integration processes. Working closely with a cross-functional team that includes project managers, analysts, and sales representatives to deliver high-quality, interactive products within deadlines. Promoting and implementing best practices in testing, accessibility, and performance optimization. Partnering with design, backend, QA, and product teams to develop reliable, user-focused solutions.

🏢 Summary: Full-time Senior Software Engineer role focused on designing and delivering scalable features and integrations for a renewable energy platform. The position involves building and maintaining large-scale systems, contributing to greenfield products, and supporting production services in a hybrid Warsaw setup. The goal is to enhance performance and automation in solar project development through robust software solutions. 🗂️ Requirements: 5+ years of software development experience, Proficiency in at least two production programming languages, Strong computer science fundamentals, Experience building and maintaining large-scale systems, Ability to work in remote or hybrid teams, Fluent English (spoken and written) 📃 Skills: Python, Java, Go, C++, JavaScript, TypeScript, Spring, Jackson, JPA, HTTP, SQL, MySQL, MariaDB, Git, Gradle, AWS, DDD 🏢 Description: Senior Software Engineer 💰 Salary: 14,000-28,000 PLN 🌎 Hybrid from Warsaw 🕦 Full-time position, long-term ☑️ Contract through Deel The company develops software that helps businesses plan and manage renewable energy projects more efficiently. Its technology platform uses data and automation to simplify complex workflows, enabling teams to design, evaluate, and deliver energy solutions at scale. The overall goal is to make clean energy projects easier to develop and deploy. Requirements: At least 5+ years of experience in software development Strong proficiency in at least two production programming languages (ideally Python and Java), though any combination of languages is acceptable Good engineering judgment based on solid computer science knowledge Experience working with teams to build and maintain large-scale systems Strong communication and collaboration skills, especially when working in remote or hybrid teams Comfortable adapting to changes in a growing product and evolving technology stack, with the ability to make practical decisions and support the team as things scale Fluent in spoken and written English (please submit your resume in English) Nice to Have: Interest in renewable energy and sustainability Experience applying Domain-Driven Design (DDD) principles Experience developing production software in at least one additional language besides Java (such as Python, Go, C++, JavaScript, or TypeScript) Familiarity with technologies such as Spring Framework, Jackson, JPA, HTTP, SQL (MySQL/MariaDB), Git, Gradle, and AWS Key Responsibilities: Design and deliver new features that improve the performance and accuracy of the platform Build integrations with key partners across the solar ecosystem to simplify end-to-end project workflows Develop new capabilities for our industry-leading solar design platform Lead the creation of new greenfield products that influence how solar systems are designed and implemented Take ownership of the services managed by your team, including participating in an on-call rotation for operational support Get to know DevsData: We are a technology consulting company and a recruitment agency, delivering software solutions to clients from Europe and the US. We work 100% remotely, in an international team, including people from Asia, London, or San Francisco. We employ people with experience in international corporations as well as students of the best technical and business universities. Find out more: https://devsdata.com/

🏢 Summary: Full-time Full Stack Software Engineer role focused on building AI-powered enterprise platforms using Java and React in a hybrid Warsaw setup. The position involves developing responsive front-end applications and scalable microservices-based back-end systems, integrating cloud services, and maintaining CI/CD pipelines. Long-term employment contract with emphasis on high-performance, secure, and maintainable solutions. 🗂️ Requirements: 5+ years experience as Full Stack Developer with Java and React.js, Strong proficiency in React.js and Redux, Strong knowledge of TypeScript, HTML5, CSS3, ES6+, Experience with state management and component-based architecture, Experience with UI libraries (Material-UI, Bootstrap, or Tailwind), Strong expertise in Java, Spring Boot, Hibernate, JPA, Experience building RESTful APIs and microservices, Knowledge of OAuth2, JWT, and session-based authentication, Experience with PostgreSQL or MySQL, Experience with MongoDB or Redis, Hands-on experience with CI/CD tools, Experience with AWS, Azure, or GCP, Experience with Docker and Kubernetes, Bachelor’s or Master’s degree in Computer Science or related field, Experience working in Agile environments 📃 Skills: Java, React, Redux, TypeScript, HTML5, CSS3, JavaScript, Spring, SpringBoot, Hibernate, JPA, REST, Microservices, OAuth2, JWT, PostgreSQL, MySQL, MongoDB, Redis, Jenkins, GitHub, GitLab, AWS, Azure, GCP, Docker, Kubernetes 🏢 Description: 💰 Salary: 21,000-22,000 PLN/month 🌎 Hybrid from Warsaw, Poland 🕦 Full-time position, long-term ☑️ Contract of Employment We are looking for a Software Engineer to join our client, a technology company that builds AI-powered platforms and consulting solutions for enterprise operations, with a strong focus on the private capital sector. The company has over ten years of experience working with high-growth and PE-backed businesses, combining deep domain expertise with advanced technology to drive measurable results. Requirements: 5+ years of professional experience as a Full Stack Developer working with Java and React.js. Strong proficiency in React.js, Redux, TypeScript, HTML5, CSS3, and modern JavaScript (ES6+). In-depth understanding of state management solutions and component-based design principles. Experience working with UI libraries/frameworks such as Material-UI, Bootstrap, or Tailwind CSS. Solid expertise in Java, Spring Boot, Hibernate, JPA, and building RESTful APIs. Experience designing and working with microservices architecture and API Gateway patterns. Knowledge of authentication and authorization approaches, including OAuth2, JWT, and session-based methods. Experience with relational databases (PostgreSQL, MySQL) as well as NoSQL solutions (MongoDB, Redis). Hands-on experience using CI/CD tools like Jenkins, GitHub Actions, or GitLab CI/CD. Familiarity with cloud platforms such as AWS, Azure, or GCP, along with containerization tools like Docker and Kubernetes. Bachelor’s or Master’s degree in Computer Science, Engineering, or a related discipline. Experience operating within Agile development environments. Strong analytical thinking and problem-solving abilities. Key Responsibilities: Build and develop dynamic, responsive, and high-performing user interface components using React.js, Redux, and modern JavaScript (ES6+). Ensure applications function consistently across different browsers while delivering a smooth user experience. Enhance front-end performance and apply best practices in UI/UX design. Design, develop, and maintain RESTful APIs and microservices using Java technologies such as Spring Boot, Hibernate, and JPA. Implement secure authentication, authorization, and effective data management solutions. Work with both relational and NoSQL databases, including PostgreSQL, MySQL, and MongoDB. Integrate external services, APIs, and cloud-based platforms into applications. Oversee deployment processes using CI/CD pipelines and containerization technologies like Docker and Kubernetes. Produce clean, efficient, and maintainable code in line with established best practices. Develop and maintain unit and integration tests for both front-end and back-end systems. Collaborate closely with UI/UX designers, product managers, and DevOps specialists. Take part in Agile/Scrum processes and support ongoing improvements to development workflows.

🏢 Summary: Hybrid Software Engineer role focused on developing and maintaining a scalable Ruby on Rails platform, building APIs, and delivering secure, high-performance solutions. The position involves implementing new features, supporting integrations with external partners, and contributing to agile development processes. The engineer will also take ownership of services and support ongoing platform reliability. 🗂️ Requirements: Minimum 3 years of professional experience as a Software Engineer, Proficiency in Ruby on Rails, Experience developing and managing APIs, Familiarity with React, Knowledge of JavaScript or TypeScript, Ability to work in a hybrid environment (Warsaw-based), Advanced written and spoken English 📃 Skills: Ruby, Rails, API, React, JavaScript, TypeScript, GraphQL 🏢 Description: Our Client, an American software company is opening a new branch in Warsaw and we are looking for a 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 3 years of professional experience as a Software Engineer good proficiency with Ruby on Rails Excellent communication skills and experience working in cross-functional teams Familiarity with React and component-based front-end frameworks 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: Software Engineer role in a long-term international project, working in a cross-functional team responsible for full product lifecycle from design to production support. The position involves backend and frontend development using modern technologies in an iterative delivery model. Hybrid work model with 5 days per month in the office. 🗂️ Requirements: Minimum 5 years of commercial software development experience, Experience with at least one programming language: Kotlin, Python, or JavaScript, Willingness to work across backend and frontend technologies, Working knowledge of Unix/Linux environments, Understanding of databases: MongoDB, Redis, PostgreSQL, Experience with HTTP APIs and RESTful services, Ability to provide production support and troubleshoot performance and security issues, Good English communication skills 📃 Skills: Kotlin, Python, JavaScript, Unix, Linux, MongoDB, Redis, PostgreSQL, REST, HTTP, .NET, C# 🏢 Description: Software Engineer (Kotlin / Python / JavaScript) Location: Kraków or Warsaw (hybrid — 5 days per month in the office) Contract type: B2B — 130–140 PLN/h Project: Long-term international project About the Role We are looking for a Software Engineer to join a collaborative product team working in an iterative delivery model. The team is responsible for the full lifecycle of the product — from design and development to production support — following the principle: “you build it, you support it.” This role offers an opportunity to work with modern technologies across backend and frontend, while continuously learning new programming languages and tools. Key Responsibilities Work in a cross-functional team of 4–6 engineers Break down requirements into user stories and deliver iteratively to production Design technical solutions aligned with architectural guidelines Provide production support, including troubleshooting bugs, performance, and security issues Identify and manage technical debt alongside new feature development Collaborate closely with team members, including pair programming Ensure high quality and maintainability of delivered solutions Requirements Minimum 5 years of relevant commercial experience Experience with at least one programming language (Kotlin, Python, or JavaScript preferred) Willingness to learn multiple technologies across backend and frontend Working knowledge of Unix/Linux environments Understanding of databases from a usage perspective (MongoDB, Redis, PostgreSQL) Experience with HTTP APIs (RESTful services) Good English communication skills (team communication in English) Nice to Have Knowledge of .NET / C# What We Offer Hybrid work model — only 5 days per month from the office (Kraków or Warsaw) Private medical care (Medicover) Sports card (Multisport or equivalent) Life insurance Long-term, stable cooperation Opportunity to work with modern technologies in an international environment Support for professional development and learning

🏢 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: Full-time hybrid Software Engineer role focused on building and scaling a data-driven platform for planning and managing renewable energy projects. The position involves developing new features, improving existing systems, and contributing to architectural decisions in a distributed team. The offer includes long-term collaboration through Deel with competitive salary. 🗂️ Requirements: 5+ years of software development experience, Strong proficiency in Python, JavaScript, TypeScript or React, Experience writing maintainable object-oriented code, Experience designing APIs, Experience with relational databases, Experience running applications in cloud environments, Solid computer science fundamentals, Understanding of Agile and DevOps principles, Fluent English (spoken and written) 📃 Skills: Python, JavaScript, TypeScript, React, APIs, SQL, PostgreSQL, Cloud, Agile, DevOps, Redux, Flask, Celery, Redis, C++, WebGL, Three.js, CUDA 🏢 Description: 💰 Salary: 14,000-28,000 PLN 🌎 Hybrid from Warsaw 🕦 Full-time position, long-term ☑️ Contract through Deel The company develops software that helps businesses plan and manage renewable energy projects more efficiently. Its technology platform uses data and automation to simplify complex workflows, enabling teams to design, evaluate, and deliver energy solutions at scale. The overall goal is to make clean energy projects easier to develop and deploy. Requirements: At least 5+ years of experience in software development Strong proficiency in Python, Javascript, Typescript or React; writing clear, maintainable, and testable object-oriented code Good engineering judgment based on solid computer science knowledge Experience with designing APIs, working with relational databases, and running applications in cloud-based environments Understanding of Agile, DevOps and Lean values Strong communication and collaboration skills, especially when working in remote or hybrid teams Comfortable adapting to changes in a growing product and evolving technology stack, with the ability to make practical decisions and support the team as things scale Fluent in spoken and written English (please submit your resume in English) Nice to Have: Educational or practical experience in areas like applied math, geometric modeling (2D/3D), or electrical and electronic systems Exposure to technologies such as state management libraries (e.g. Redux), backend frameworks (like Flask), task queues and caching layers (Celery, Redis), relational databases (PostgreSQL), as well as lower-level or graphics-focused tools including C++, WebGL, Three.js, or GPU computing (CUDA) Strong interest in improving how software is built and delivered, including automating workflows, setting up pipelines, working with containers, and enhancing visibility and overall developer experience Key Responsibilities: Contribute to both ongoing systems and brand-new features, playing an active role in a distributed team environment Support and guide teammates through meaningful code feedback, collaborative coding sessions, and technical direction Question existing approaches, explore better alternatives, and advocate for solutions that scale effectively Take ownership of work items from early concept and research all the way through to release Partner closely with cross-functional groups, product, design, QA, and customer-facing teams to move important efforts forward Get to know DevsData: We are a technology consulting company and a recruitment agency, delivering software solutions to clients from Europe and the US. We work 100% remotely, in an international team, including people from Asia, London, or San Francisco. We employ people with experience in international corporations as well as students of the best technical and business universities. Find out more: https://devsdata.com/

🏢 Summary: Senior Frontend Engineer role focused on building and evolving a browser-based 3D design platform for modeling real-world physical systems. The position involves owning frontend features end-to-end, contributing to frontend architecture, collaborating across teams, and occasionally working with backend systems in a hybrid Warsaw-based setup. 🗂️ Requirements: 5+ years building production user interfaces in JavaScript and TypeScript, React experience, Knowledge of component-based frontend architecture, Experience integrating frontends with backend services and APIs, Ability to own features end-to-end, Willingness to work with backend code, Knowledge of system design, testing, refactoring, and technical writing, CS degree or equivalent production software experience, Fluent written and spoken English 📃 Skills: TypeScript, JavaScript, React, GraphQL, three.js, PostgreSQL, Ruby, Rails, Python, Playwright, Git, CAD 🏢 Description: Salary: 24,000 - 28,000 PLN/month Hybrid, Warsaw (2 Days/Week) Full-time Employment contract (UOP) via Employer of Record We're looking for a Senior Frontend Engineer for a software company whose platform lets professionals design real-world physical systems in an interactive, browser-based 3D environment. You'd join the team that owns the core of the product: the design surface where users model actual sites in a 3D canvas, backed by CAD tooling and a data model that keeps designs accurate to the physical world. Working stack: - TypeScript - JavaScript - React - GraphQL - three.js - PostgreSQL - Ruby on Rails - Python A senior individual contributor role reporting into engineering leadership. You'll own features end-to-end, from technical design through to production support, and help steer the frontend architecture the team relies on. Requirements: - 5+ years building production user interfaces in JavaScript and TypeScript - React experience and a firm grasp of component-based frontend architecture - Experience wiring frontends to backend services and APIs - Comfort owning features end-to-end, from scoping through to production - Willingness to step beyond the frontend when a feature calls for it, including reading and touching backend code (Ruby on Rails familiarity is a plus) - Engineering fundamentals: system design, testing, refactoring, and clear technical writing - A CS degree or an equivalent hands-on track record shipping production software - Fluent in written and spoken English Nice to Have: - GraphQL in production - three.js or another 3D graphics library - Ruby on Rails or Python - Playwright or a comparable end-to-end testing framework - Git in a collaborative, multi-engineer codebase - Any exposure to CAD software - Experience with distributed teams in a hybrid setup Key Responsibilities: - Build and ship frontend experiences that make designing faster and more accurate - Partner with Product, Design, and Engineering to scope, build, and release features - Write clean, well-tested code and raise the bar through code reviews and technical discussions - Strengthen reliability with automated tests and a share of the team's on-call rotation - Contribute to shared frontend architecture, tooling, and technical standards - Pick up backend work when it's needed to land the features you own - Support a collaborative engineering culture through mentoring, planning, and cross-team work