Senior Full-Stack Software Developer

About UsRuby Labs is an innovative technology company dedicated to developing and managing cutting-edge consumer products that span the health, education, and entertainment sectors. Our dynamic teams are at the forefront of consumer-driven solutions, and we are on the lookout for enthusiastic professionals to join our journey. Discover more about our mission…

Playson is a prominent online gaming provider, established in 2012, renowned for delivering comprehensive gaming solutions that leverage cutting-edge technologies and in-depth market insights tailored for top-tier iGaming operators.We are currently on the lookout for a Senior Full-Stack Engineer to join our promotional features team. This role is ideal for someone with a strong backend focus (Node.js/TypeScript) while also possessing confidence in frontend technologies (React). You'll be responsible for designing, building, and refining features that are not only robust and scalable but also a delight for users.If you are passionate about products, eager to tackle complex engineering challenges, and have a rapid 'Proof of Concept first' mindset with a strong sense of ownership, we would love to connect with you.Key Responsibilities:Craft, develop, and sustain backend services for promotional features utilizing Node.js/TypeScript.Create and enhance the frontend UI in React (with Redux or modern state management), prioritizing usability and performance.Optimize existing architectures for high throughput, minimal latency, and exceptional scalability.Guide technical decisions, contributing to the advancement of our SaaS solutions and platform evolution.Collaborate with a diverse, cross-functional team and proactively suggest improvements.Uphold code and architectural excellence through code reviews, best practices in the software development lifecycle, and automation.Ensure quality by writing unit, integration, and end-to-end tests; and drive observability and performance metrics.Participate in on-call rotations to maintain system reliability and availability.

Role Overview Ruby Labs is hiring a Senior Next.js Full Stack Engineer based in the European Union. This role focuses on building and maintaining dynamic web applications as part of a collaborative development team. Projects often involve new features and technical challenges that require strong problem-solving skills and hands-on experience. What You Will Do Develop and enhance web applications using Next.js and related technologies Work closely with other engineers to deliver high-quality, maintainable code Contribute ideas and solutions to technical discussions within the team Take on new challenges as projects evolve Who We’re Looking For Significant experience with Next.js and full stack web development Comfort working in a team setting and sharing knowledge with peers Motivation to learn and adapt to new technologies and project needs Based in the European Union

Playson, a premier online gaming supplier established in 2012, has garnered global acclaim in the iGaming sector. We deliver comprehensive gaming solutions powered by cutting-edge technologies and thorough market analysis tailored for leading iGaming operators.Our Game Tribe is on the lookout for a Senior Full-Stack Engineer. In this pivotal role, you will work in close collaboration with the Head of Gamification and fellow engineers to design, develop, and enhance game services. Your contributions will focus on:Developing a robust slot game engineCreating microservices for functionalities such as fraud detection and release processesConducting R&D on game mechanics, mathematical packages, and innovative gameplay featuresEngaging in hypothesis testing and rapid prototyping with a PoC-first approachYour Responsibilities:Design, develop, and maintain backend services for promotional features using Node.js/TypeScript.Enhance the frontend UI utilizing Pixi.js and Phaser.js, ensuring optimal usability and performance.Optimize existing systems for maximum throughput, minimal latency, and scalability.Lead technical decision-making and contribute to the evolution of our SaaS solutions and platforms.Collaborate with a geographically-distributed, cross-functional team; proactively suggest enhancements.Uphold code and architectural excellence through reviews, adherence to SDLC best practices, and automation.Take ownership of quality by writing unit, integration, and end-to-end tests; drive observability and performance.Participate in on-call rotations to maintain system reliability and availability.

Senior Full Stack Engineer (Java & Angular) , Zartis, European Union About Zartis Zartis partners with organizations across the globe to deliver technology solutions that make a real difference. Our teams specialize in AI-driven platforms, secure APIs, and cloud-native engineering. With engineering hubs across EMEA and LATAM, we work with clients in financial services, healthcare, life sciences, and energy. Engineers at Zartis collaborate on projects from strategy through delivery, helping clients adopt advanced technologies and solve complex challenges. The company values an inclusive culture where trust and innovation guide the way forward. Role Overview This Senior Full Stack Engineer role focuses on a fintech project. The team is distributed and values diverse backgrounds. The work centers on developing financial process automation tools that improve productivity, reduce costs, and support regulatory compliance. What You Will Do Design, build, and deploy scalable full-stack applications using Java (Spring Boot) on the backend and AngularJS on the frontend. Work hands-on across the stack, including Node.js services and cloud-native integrations. Act as a technical leader, mentoring and guiding engineers within the team. Collaborate with stakeholders to define architecture, technical direction, and best practices. Promote high engineering standards through code reviews, testing, and CI/CD processes. Support the ongoing migration from Azure to AWS, working closely with stakeholders. Identify and implement improvements to system performance, scalability, and reliability. Make key technical decisions aligned with long-term product and platform goals. What We’re Looking For Extensive experience in full-stack software development, especially with Java and Spring Boot. Track record of building scalable applications and leading technical projects. Strong communication skills and ability to collaborate with diverse teams. Attention to detail and strong problem-solving abilities.

Company Overview At Toloka AI, we are at the forefront of creating data that fuels innovative GenAI models. Collaborating with leading labs, tech giants, esteemed AI startups, enterprises, and non-profit research organizations globally, we leverage a unique blend of Experts, Crowd, and Tech Platform to enhance AI's reasoning and safety evaluations. Our team comprises specialists across over 50 domains, from medical professionals to engineers, and we proudly represent a diverse global crowd from over 100 countries, speaking more than 40 languages. As a well-funded startup, we serve an impressive client portfolio, including Anthropic, Amazon, Microsoft, Poolside, Recraft, and Shopify. Recently, we secured strategic investments led by Bezos Expeditions and Nebius Group, with participation from Mikhail Parakhin, CTO of Shopify, who is now our Chairman of the Board. Our remote-first team is distributed across the globe, including locations like the USA, UK, Netherlands, Israel, Czech Republic, and Serbia. Role Overview We are in search of a Senior QA Engineer who possesses the ability to think critically beyond mere test cases. You should have a profound understanding of our product, recognizing what truly matters and helping the team to maintain speed without compromising quality. This role is not suited for those who require strict processes; you will collaborate with frontend, backend, and ML teams, each with distinct release flows, to strike the right balance between speed and quality while guiding the team effectively. Key Responsibilities Take comprehensive ownership of quality—from reviewing requirements and developing test strategies to managing bug reports, tracking known issues, and identifying bottlenecks. Ensure quality across the entire system—from the AI agent and orchestration layer to user interfaces. Design and maintain automated tests that consider non-deterministic AI behavior. Debug issues within a multi-component distributed system, pinpointing where failures occur. Identify high-risk areas, prioritize effectively, and know when to halt. Collaborate with AI tools to enhance testing and quality assurance.

Join Our TeamAt Ruby Labs, a pioneering technology company, we are dedicated to developing and managing innovative consumer products across health, education, and entertainment sectors. Our dynamic teams are at the forefront of consumer-oriented innovations, and we are eager to welcome passionate individuals to join our mission. Discover more about us here.Your RoleWe are excited to announce an opening for a Lead Full-Stack Engineer to spearhead the development of a new Direct-to-Consumer product within the AI sector. As a Lead Engineer, you will guide an engineering squad responsible for a crucial segment of our product, setting the technical vision and ensuring high standards for engineering quality and delivery.In this role, you will create and sustain scalable systems utilizing Next.js, TypeScript, React, and Redis. You will also oversee the development process, manage release schedules, perform code reviews, and provide mentorship to fellow engineers. A key requirement for this position is a proven track record in developing AI-driven tools or applications.You will collaborate closely with product leadership and management to guarantee that our engineering team consistently delivers reliable and high-performing features.

About Us:Zartis is a leading digital solutions provider specializing in technology strategy, software engineering, and product development. We collaborate with organizations across various sectors including financial services, MedTech, media, logistics technology, renewable energy, EdTech, and e-commerce. Our engineering hubs in EMEA and LATAM are home to a diverse group of skilled professionals driving business success and enhancing digital capabilities through application development, software architecture, CI/CD, business intelligence, QA automation, and cutting-edge technology integrations.We are currently seeking a Senior Software Engineer to join our team and work on an exciting project within the logistics sector.Project Overview:You will be joining a talented and diverse team dedicated to fostering an inclusive culture grounded in trust and innovation. As part of a distributed team, you will support a logistics leader that offers expert consulting, specialized software, and managed services (4PL) to streamline end-to-end logistics operations.We are looking for a candidate with strong communication skills, a proactive approach, and a solid background in building software from the ground up while maintaining attention to detail.Your Responsibilities:Design and develop backend components that serve as the foundation of our digital products, utilizing Java and Spring Boot as your primary toolkit.Implement and maintain well-structured RESTful APIs, adhering to best practices in API design to ensure reliability, clarity, and long-term maintainability.Engage in the complete software development lifecycle from ideation and implementation to testing and deployment, taking ownership of clean, efficient, and maintainable code.Collaborate closely with frontend, DevOps, and QA teams to ensure seamless integration across systems and contribute to delivering a smooth, high-quality user experience.Participate in code reviews, share innovative ideas, and assist in evolving our engineering practices.

About Us:Zartis is a leading digital solutions provider specializing in technology strategy, software engineering, and product development. We collaborate with companies across various sectors including financial services, MedTech, media, logistics technology, renewable energy, EdTech, and e-commerce. Our engineering hubs in EMEA and LATAM are populated by skilled professionals dedicated to driving business success and enhancing digital capabilities through application development, software architecture, CI/CD, business intelligence, QA automation, and technology integrations. Role Overview: We are seeking a passionate Senior Software Engineer to join our team and contribute to a transformative project in the digital mental health sector. This role involves working with a diverse group of talented individuals committed to fostering an inclusive culture rooted in trust and innovation. As part of a distributed team, you will help revolutionize mental health care by developing the UK’s largest platform designed to support and empower young people in managing their mental well-being. You will play a key role in determining the technical direction and building robust, scalable systems that guide users to the assistance they need. Key Responsibilities: - Design, implement, and manage a range of Node.js backend services, React-based web applications, and React Native mobile experiences that form the foundation of our platform.- Take complete ownership of features from conception to deployment, demonstrating accountability and a customer-focused impact.- Ensure the longevity of a legacy platform through proactive maintenance, strategic enhancements, and high-quality technical support.- Engage in system design and architectural improvements.- Champion best practices in trunk-based development, automated testing, CI/CD, and infrastructure as code.- Take charge of system performance, resilience, observability, maintainability, security, and accessibility.- Collaborate across disciplines and mentor peers through pair programming, code reviews, and knowledge sharing.

Senior Data Engineer (Snowflake)About Zartis:Zartis is a premier global partner in AI transformation and technology consulting, where skilled engineers and technologists collaborate on groundbreaking innovations. We work hand-in-hand with forward-thinking organizations to design, develop, and scale technology solutions that create substantial impacts.Our teams possess extensive expertise in AI-driven platforms, secure API architectures, and cloud-native engineering. You will engage in substantial projects that hasten the adoption of advanced technologies, guiding them from strategic planning and discovery through to comprehensive product delivery, and transforming intricate challenges into quantifiable results.With engineering hubs across EMEA and LATAM, and enduring partnerships in sectors such as financial services, healthcare and life sciences, and energy and climate, we provide opportunities to work on projects that truly matter. Here, you will not only construct technology — you will influence business outcomes and advance your career alongside industry leaders.We are currently seeking a Senior Data Engineer to contribute to an exciting project within the media sector.Project Overview:We invite a talented Senior Data Engineer to join our team for a key project in the media sector, focused on developing innovative data products for a prominent US media company. Our team is composed of diverse individuals from various backgrounds, and we are dedicated to fostering an inclusive culture grounded in trust and innovation.You will be an integral part of a distributed team working on two pioneering product streams — the AI Solutions Pod and Rights360 — utilizing a modern, Snowflake-native technology stack. Your responsibilities will include designing and developing scalable, impactful systems, contributing to innovative solutions that integrate data, automation, and intelligent technologies to address real business challenges and promote efficient, insight-driven decision-making in dynamic environments.We seek a candidate who embodies a full-stack, data-driven product-building mindset, comfortable taking ownership of problems from inception to resolution and delivering solutions directly to end-users.

Zartis is a technology consulting partner specializing in AI transformation. Teams at Zartis support clients across industries such as financial services, healthcare, life sciences, and energy. The company’s work covers areas like AI-driven platforms, secure API architectures, and cloud-native engineering. Projects often involve moving from strategic planning to full product delivery, addressing complex technical challenges and producing measurable results. With engineering centers throughout EMEA and LATAM, Zartis brings together colleagues who value innovation and business impact. The company offers the chance to contribute to projects that matter, working in a collaborative environment. Role overview The Senior .NET Software Engineer – E-Commerce Innovation position centers on a project within the e-commerce sector. The team partners with a major platform trusted by global brands, aiming to enhance digital shopping experiences. The main objective is to deliver scalable solutions that make online shopping safer, simpler, and faster for consumers worldwide. What you will do Work as part of a distributed engineering team developing new technologies to address real business needs. Contribute to designing and building scalable systems for e-commerce applications. Collaborate with colleagues from varied backgrounds in a culture built on trust and inclusion. Participate in all stages of product development, from planning to delivery. Requirements Experience building scalable systems, ideally in e-commerce or related domains. Strong communication skills and a proactive problem-solving approach. Demonstrated ownership mentality and attention to detail. Comfort working in a distributed, production-focused setting. Location This position is open to candidates based in the European Union.

Join Zartis as a Senior Software Engineer focused on green energy solutions:At Zartis, we are dedicated to delivering cutting-edge digital solutions across various sectors, including financial services, MedTech, media, logistics, renewable energy, EdTech, and e-commerce.As a part of our dynamic engineering teams located in EMEA and LATAM, you will collaborate with talented professionals to enhance application development, software architecture, CI/CD, business intelligence, QA automation, and technology integrations.In this role, you will join the API Platform team, where you will develop and maintain crucial components of a retail energy platform. Your responsibilities will include creating a high-performance GraphQL API and an event gateway to ensure efficient, low-latency data access for our global clients in the energy sector.We value collaboration and encourage an inclusive culture where teamwork thrives. You will engage in agile practices, address complex challenges, and utilize Infrastructure as Code (IaC) for managing Kubernetes deployments.

Zartis partners with organizations around the globe to deliver technology consulting and AI transformation. The team focuses on AI-driven platforms, secure API design, and cloud-native engineering. With engineering hubs throughout EMEA and LATAM, Zartis supports clients in sectors such as financial services, healthcare, life sciences, and energy. Collaboration, measurable outcomes, and career growth are core values, and the company emphasizes working alongside experienced professionals. Role overview This Senior Software Engineer (Node.js / AWS) position centers on a project in the education technology sector. The distributed team includes people from a range of backgrounds, all brought together by a culture of trust and innovation. The work aims to build solutions that improve university programs, student services, exam preparation, and corporate training worldwide. Candidates who are proactive, communicate clearly, make thoughtful decisions, and enjoy building software from the ground up with attention to detail will thrive in this role. What you will do Develop RESTful services using AWS API Gateway and Lambda with Node.js and NestJS. Design and implement scalable, event-driven microservice architectures with Amazon EventBridge, SNS, SQS, RabbitMQ, and AmazonMQ. Lead engineering initiatives and collaborate with cross-functional teams and stakeholders. Integrate external APIs into core systems. Use GitHub Copilot in daily development, including AI-assisted code reviews within CI/CD pipelines. Requirements Minimum 6 years of experience with Node.js and frameworks such as Express, NestJS, or Koa. Hands-on experience with AWS, particularly Lambda (serverless) and infrastructure-as-code using Terraform. Strong skills in TypeScript. Experience working with message brokers and asynchronous communication in distributed systems. Proficiency with Git and established version control practices. Familiarity with Agile or Scrum methodologies. Location This position is open to candidates based in the European Union.

Join Playson, a premier online gaming supplier established in 2012, recognized globally for our innovative gaming solutions tailored for leading iGaming operators. We leverage cutting-edge technology and comprehensive market insights to deliver exceptional products.We are in search of a dedicated Senior Front-End JavaScript Game Developer who is passionate about creating high-performance games and is eager to contribute fresh ideas while focusing on scalability. This role is ideal for a committed developer ready to engage with game engines and spearhead new feature development.

Join our dynamic team at ruby-labs as a Senior UI/UX Developer with a focus on Artificial Intelligence. In this role, you will leverage your extensive experience in user interface and user experience design to create innovative solutions that enhance user interactions. Your expertise in AI technologies will be essential as we develop cutting-edge applications that push the boundaries of what's possible.

About lemlistAt lemlist, we are dedicated to empowering businesses around the globe with our innovative B2B SaaS solutions aimed at facilitating growth.Currently, we are generating over $43M in Annual Recurring Revenue (ARR) while maintaining:A bootstrapped modelStrong profitabilityA nimble team of 140 talented individuals, thriving in a remote-friendly environmentOwnership by our founder and entrepreneur, Guillaume Moubeche, ensuring we retain the freedom to innovateWe operate across two primary business lines:Sales Engagement through our flagship product lemlist, contributing $38M ARR with over 40% growth year-on-yearPersonal Branding via Taplio & Tweet Hunter, which generates $5M ARROur ambition is to establish lemlist as a leader in the Sales Tech industry, and we live by our mantra: Keep growing.Job DescriptionWe are on the lookout for a Senior Fullstack TypeScript Developer to become part of our dynamic team. Your role will involve designing and implementing cutting-edge features for our SaaS offerings. We desire an individual who is self-driven, passionate about technology, and thrives on tackling complex challenges.Your Responsibilities Include:Crafting and developing innovative features from the ground up, encompassing both frontend and backend aspects, with a focus on enhancing user experience and product capabilities.Assuming the role of technical lead within your team, promoting excellence and establishing best practices.Refining the codebase through systematic refactoring, debugging, and performance optimization.Managing multiple projects concurrently with agility and efficiency.Providing technical support to the customer service team by resolving technical issues promptly and effectively.Fostering knowledge sharing and capacity building by mentoring fellow developers to elevate the overall team skillset and productivity.Key Outcomes ExpectedWithin the first 3 months, you will achieve:A successful onboarding experience and seamless integration into the team.An in-depth understanding of our B2B SaaS products and their technical requirements.

Zartis partners with organizations worldwide to deliver technology consulting and AI transformation. Teams collaborate closely with clients to design, build, and scale solutions that address real business needs. With engineering centers in EMEA and LATAM, Zartis supports industries such as financial services, healthcare, life sciences, and energy and climate. Engineers at Zartis bring expertise in AI-driven platforms, secure API architectures, and cloud-native development. Projects cover the entire lifecycle, from strategy and discovery through to product delivery, with a focus on solving complex problems and making a measurable impact. Team members have opportunities to contribute to business growth and learn from experienced professionals across sectors. Role overview This Senior Software Engineer position focuses on full-stack development for a fintech project. The team values inclusion, trust, and innovation, bringing together people from diverse backgrounds to solve challenges in financial technology. Project focus The role involves joining a distributed group working on financial process automation tools. The aim is to increase productivity, lower costs, and support compliance for client organizations. Work centers on building solutions that streamline financial operations and deliver measurable business value. Main responsibilities Design, build, and maintain high-performance, reusable full-stack applications. Collaborate with Product and cross-functional teams to define and deliver end-to-end technical solutions. Contribute in an Agile environment, using Lean principles focused on CI/CD, automated testing, and continuous delivery. Follow established engineering best practices, code quality standards, and development processes throughout the delivery lifecycle. Take ownership of technical design and provide accurate estimates for complex tasks and projects. Engage with customers and stakeholders to ensure deliverables meet requirements and expectations. Monitor solution quality and stability, suggest improvements, and propose changes as needed. Requirements At least 5 years of experience building applications in Java, with a focus on Spring or Spring Boot. Hands-on experience with React and TypeScript. Strong understanding of event-driven architecture and microservices. Excellent communication skills and a proactive approach to decision-making. Attention to detail and experience developing software from the ground up. Location This position is open to candidates based in the European Union.

About Zartis Zartis partners with organizations across the globe to drive AI transformation and deliver technology consulting services. Our engineers and technologists work on projects that shape how advanced technologies are integrated and scaled. With deep expertise in AI-driven platforms, secure API architectures, and cloud-native engineering, our teams support clients from planning and discovery through to product delivery. We operate engineering hubs throughout EMEA and LATAM, collaborating with clients in financial services, healthcare, life sciences, energy, and climate. Projects at Zartis offer the chance to influence business outcomes and develop alongside leaders in the field. We are currently seeking a Senior Software Engineer (Java, Node.js) to join a fintech project in the European Union. Project Overview This role involves working with a distributed team to build financial process automation solutions. The aim is to improve productivity, reduce costs, and ensure compliance with industry regulations. Our environment values trust, innovation, and inclusion, bringing together professionals from a range of backgrounds. The ideal candidate communicates clearly, makes thoughtful decisions, takes initiative, and pays close attention to detail. Experience building software from the ground up is highly valued. What You Will Do Design and maintain data pipelines and ETL/ELT workflows, handling batch extraction, transformation, and loading into analytics-ready repositories. Build and manage event-driven, serverless data processing systems using AWS tools such as S3, EventBridge, Lambda, and Athena. Develop Python-based components for data parsing and transformation within Lambda environments. Write and optimize SQL queries for data validation and analysis with Athena. Create and maintain embedded analytics dashboards for customer-facing reporting using AWS QuickSight. Provision and manage data infrastructure with Terraform to ensure consistent deployments across environments. Implement CI/CD pipelines and set up monitoring and alerting to support reliable data platform operations. Improve and extend existing pipeline frameworks while working within legacy systems.

Join Our Team as a Senior Fullstack Engineer!At Zartis, we are a pioneering digital solutions provider specializing in technology strategy, software engineering, and product development. Our mission is to empower businesses across various sectors, including financial services, MedTech, media, logistics technology, renewable energy, EdTech, and e-commerce.With engineering hubs located in EMEA and LATAM, we are committed to delivering exceptional digital solutions that drive business success. Our talented professionals excel in application development, software architecture, CI/CD, business intelligence, QA automation, and new technology integrations.We are currently seeking a Senior Fullstack Engineer to contribute to a transformative project in the financial sector. You will be part of a diverse and inclusive team that prioritizes trust and innovation while working with leading nutritional clients to offer a wide array of investment and advisory services.About the Project:Our client is on a mission to modernize and scale their digital platforms, placing technology at the core of providing secure and high-quality financial services. You will collaborate with a distributed team to develop cutting-edge technologies that address real business challenges. Strong communication skills and experience in building software from the ground up will be essential for this role.Key Responsibilities:- Collaborate closely with business users, vendors, and stakeholders to design solutions that meet both functional and non-functional requirements. Create and maintain comprehensive project documentation including business requirements and design documents.- Lead the design and implementation of new components and features, managing key tasks and providing regular updates to stakeholders.- Work with the testing team to ensure all solutions are thoroughly tested, including the creation and execution of automated test scripts. Assess new technologies and third-party solutions.- Collaborate with existing and new vendors to integrate third-party solutions effectively.

Join AppFollow, a leading App review management and ASO platform dedicated to empowering app developers and product teams.We aim to simplify the daily tasks of app developers, product managers, marketing teams, and customer support professionals. AppFollow enables the collection and management of app and game data, boosts app ratings, enhances store rankings, and fosters user loyalty.This fully remote opportunity is perfect for a Senior Backend Engineer eager to contribute to AppFollow's global expansion. You will work on the essential backend systems that facilitate user engagement with product data, ensuring quick and efficient access to diverse datasets, while supporting flexible analytics and reporting capabilities across various data types.Key Responsibilities- Enhance and optimize the core backend functionalities of the AppFollow platform.- Develop and maintain systems for user interaction with product data.- Design and implement a source-agnostic data storage layer that ensures efficient, rapid, and dependable data delivery to users.- Create and support systems that generate insights from various customer and product data, including ratings, reviews, and other data sources, emphasizing customizable reporting.- Develop and support internal and public APIs for core data entities, adhering to API-first principles.- Design, build, maintain, and document a reliable, secure, efficient, and scalable codebase.- Collaborate with other developers to design and enhance the overall system architecture.- Engage with legacy services.- Work with the Platform team to deploy applications across various environments, ensuring smooth operations while adopting established standards and practices.Your Profile - 5+ years of experience in backend development with a strong focus on scalability and performance.