Senior TypeScript/Node.js Developer (Swedish Ad Platform)

🏢 Summary: Senior TypeScript/Node.js Developer role focused on transforming a global AdTech platform into a scalable, API-first, multi-tenant microservices architecture on AWS serverless. The position involves designing high-performance services, governing API standards, and driving architectural standardization toward a reusable platform model. Work centers on performance, reliability, cost-efficiency, and strict data isolation at scale. 🗂️ Requirements: 7+ years production experience as Back-End Developer, Strong expertise in TypeScript, Strong expertise in Node.js, Experience designing API-first microservice architectures, Deep knowledge of AWS serverless: Lambda, API Gateway, DynamoDB, EventBridge, Experience with IaC tools: CloudFormation or Terraform, Experience designing RESTful APIs, Experience designing GraphQL APIs, Understanding of multi-tenant architecture, Experience with logical data isolation patterns, AdTech domain knowledge, Experience building standardized multi-client platforms, Focus on performance and reliability in distributed systems, Upper-Intermediate English level 📃 Skills: TypeScript, Node.js, AWS, Lambda, APIGateway, DynamoDB, EventBridge, CloudFormation, Terraform, REST, GraphQL, OpenAPI, JWT, AdCP, Microservices, Serverless, IaC 🏢 Description: Are you passionate about building high-performance platforms that serve millions of users worldwide? We are looking for a Senior TypeScript/Node.js Developer to join our team and help transform a global AdTech product into a scalable, platform-first architecture. At Sigma Software, we value engineering excellence, innovation, and collaboration, offering the opportunity to work on cutting-edge projects with world-class customers. You will have the chance to work with advanced AWS serverless solutions, contribute to strategic architectural decisions, and enjoy a supportive environment with professional growth opportunities. CUSTOMER Our Customer is a Sweden-based AdTech company specializing in advanced self-serve advertising platforms that automate direct transactions between advertisers and major global publishers. Their technology removes traditional friction in ad sales by enabling automation, transparency, and operational efficiency at scale. Platforms are trusted by internationally recognized publishers including TripAdvisor, Bloomberg, The Washington Post, Opera, and Dow Jones, handling millions of transactions worldwide. PROJECT The project is a strategic architectural transformation toward a Platform-First approach. The company is transitioning from monolithic, client-specific implementations to a standardized, API-driven, multi-tenant ecosystem of reusable microservices. These services power the entire product suite, remaining independent, scalable, and decoupled from frontend or customer-specific customization. Key Technologies: TypeScript, Node.js, AWS Lambda, API Gateway, DynamoDB, EventBridge, IaC tools (CloudFormation or Terraform), RESTful/GraphQL APIs. RESPONSIBILITIES Own and govern API design by defining and maintaining strict OpenAPI specifications before implementation begins Design and implement high-performance microservices using TypeScript and Node.js within a serverless AWS architecture Drive FinOps excellence by architecting solutions with AWS Lambda, API Gateway, DynamoDB, and EventBridge to achieve a Scale-to-Zero cost model Enforce logical isolation patterns across services, ensuring strict tenant data separation via JWT policies and Row-Level Security Maintain adherence to the Ad Context Protocol (AdCP) across all data models for consistent AdTech data language Develop reusable “Golden Path” templates, shared libraries, and engineering best practices Conduct rigorous code reviews focusing on latency (<200ms), availability (99.99%), and observability Translate product and commercial requirements into scalable technical specifications Contribute to evolving the overall platform architecture toward standardization and reusability REQUIREMENTS At least 7 years of production experience as a Back-End Developer Strong hands-on expertise with TypeScript and Node.js Proven experience designing API-first microservice architectures Deep expertise in AWS serverless ecosystem: Lambda, API Gateway, DynamoDB, EventBridge, and IaC tools (CloudFormation or Terraform) Solid AdTech domain knowledge, including advertising data models and workflows Extensive experience designing RESTful and GraphQL APIs with versioning, backward compatibility, and documentation Strong understanding of multi-tenant architecture and logical data isolation patterns Experience building standardized platforms for multiple clients instead of custom solutions Strong focus on performance, reliability, and observability in distributed systems At least an Upper-Intermediate level of English WILL BE A PLUS Experience as a Lead Back-End Developer PERSONAL PROFILE Proactive and detail-oriented with a strong sense of ownership Enjoys solving complex architectural challenges Thrives in collaborative, cross-functional teams Committed to delivering high-quality solutions meeting demanding performance and reliability standards

🏢 Summary: Senior TypeScript/Vue.js Developer role focused on leading front-end architecture for a next-generation AdTech platform transitioning from a monolithic system to a scalable, API-driven ecosystem. The position involves designing high-performance, modular Vue 3 applications, collaborating on API contracts, and deploying solutions within a microservices-based AWS environment. The role combines hands-on development, architectural ownership, and technical leadership. 🗂️ Requirements: 7+ years JavaScript experience, Strong Vue.js expertise, Strong TypeScript expertise, Deep knowledge of Vue3 CompositionAPI, Experience designing API contracts with backend teams, Experience with complex asynchronous data flows, Experience deploying frontend applications in AWS, Hands-on experience with Vite, Hands-on experience with Cypress, Hands-on experience with Vitest, AdTech domain knowledge, Upper-Intermediate English 📃 Skills: JavaScript, TypeScript, Vue, Vue3, CompositionAPI, AWS, Vite, Cypress, Vitest, APIs, Microservices, DevOps, AdTech, Architecture, Testing 🏢 Description: Are you passionate about building scalable, high-performance front-end solutions? At Sigma Software, we are looking for a Senior TypeScript/Vue.js Developer to join our distributed team and help shape the future of a next-generation AdTech platform. You will work alongside talented engineers and contribute to transforming a complex monolithic system into a modern, API-driven architecture. We at Sigma Software value innovation, collaboration, and professional growth. Joining us means working on impactful projects with global reach, while enjoying a supportive environment that encourages learning and knowledge sharing. Customer Our Customer is a Swedish AdTech company that transforms the way publishers and advertisers interact. They provide state-of-the-art self-serve advertising platforms that enable seamless, direct transactions between advertisers and some of the world’s largest publishers. Their mission is to make advertising more accessible, automated, and efficient through innovative technology. Together, we serve globally recognized clients, including TripAdvisor, Bloomberg, The Washington Post, Opera, Dow Jones, etc. Project The project represents a strategic transition to a Platform-First, API-driven architecture. The company is moving away from monolithic, client-specific codebases to a standardized ecosystem. As a Senior TypeScript/Vue.js Developer, you will be the technical visionary for the platforms, ensuring the technology remains high-performing and scalable. Responsibilities Define and lead front-end architecture strategy using Vue 3 with TypeScript, focusing on modularity, scalability, and performance Collaborate with the Platform Team to design, document, and enforce API contracts optimized for low-latency AdTech requirements Participate in system design to align front-end requirements with back-end architecture, supporting complex UI states and asynchronous data flows Partner with DevOps to deploy and scale front-end solutions in AWS, ensuring smooth integration within a microservices ecosystem Mentor and guide engineering teams, promoting an API-first mindset and rigorous TypeScript usage Requirements At least 7 years of hands-on experience in JavaScript and modern front-end development Strong expertise in Vue.js and TypeScript, including deep knowledge of Vue 3 Composition API Proven ability to collaborate with back-end/platform teams to design robust API contracts and manage complex data orchestration Experience deploying and scaling front-end applications in AWS environments Hands-on experience with Vite and modern testing tools (Cypress, Vitest) Solid AdTech domain knowledge, including advertising data models and workflows Upper-Intermediate English proficiency Personal Profile Strong leadership and mentoring skills Excellent communication and collaboration abilities Analytical mindset with a focus on scalability and maintainability

🏢 Summary: Senior TypeScript/Vue.js Developer role focused on leading front-end architecture for a next-generation AdTech platform transitioning from monolithic to API-driven architecture. The position involves building scalable, high-performance Vue 3 applications, defining API contracts, and ensuring seamless integration within a microservices ecosystem on AWS. You will drive technical strategy and support modernization of a complex advertising platform. 🗂️ Requirements: 7+ years of JavaScript and modern front-end development experience, Strong expertise in Vue.js and TypeScript, Deep knowledge of Vue 3 Composition API, Experience designing and integrating API contracts with back-end teams, Experience with AWS deployment and scaling of front-end applications, Hands-on experience with Vite, Experience with Cypress and Vitest, AdTech domain knowledge including advertising data models and workflows 📃 Skills: JavaScript, TypeScript, Vue, Vue3, CompositionAPI, AWS, Vite, Cypress, Vitest, APIs, Microservices, AdTech 🏢 Description: Are you passionate about building scalable, high-performance front-end solutions? At Sigma Software, we are looking for a Senior TypeScript/Vue.js Developer to join our distributed team and help shape the future of a next-generation AdTech platform. You will work alongside talented engineers and contribute to transforming a complex monolithic system into a modern, API-driven architecture. We at Sigma Software value innovation, collaboration, and professional growth. Joining us means working on impactful projects with global reach, while enjoying a supportive environment that encourages learning and knowledge sharing. Customer Our Customer is a Swedish AdTech company that transforms the way publishers and advertisers interact. They provide state-of-the-art self-serve advertising platforms that enable seamless, direct transactions between advertisers and some of the world’s largest publishers. Their mission is to make advertising more accessible, automated, and efficient through innovative technology. Together, we serve globally recognized clients, including TripAdvisor, Bloomberg, The Washington Post, Opera, Dow Jones, etc. Project The project represents a strategic transition to a Platform-First, API-driven architecture. The company is moving away from monolithic, client-specific codebases to a standardized ecosystem. As a Senior TypeScript/Vue.js Developer, you will be the technical visionary for the platforms, ensuring the technology remains high-performing and scalable. Responsibilities Define and lead front-end architecture strategy using Vue 3 with TypeScript, focusing on modularity, scalability, and performance Collaborate with the Platform Team to design, document, and enforce API contracts optimized for low-latency AdTech requirements Participate in system design to align front-end requirements with back-end architecture, supporting complex UI states and asynchronous data flows Partner with DevOps to deploy and scale front-end solutions in AWS, ensuring smooth integration within a microservices ecosystem Mentor and guide engineering teams, promoting an API-first mindset and rigorous TypeScript usage Requirements At least 7 years of hands-on experience in JavaScript and modern front-end development Strong expertise in Vue.js and TypeScript, including deep knowledge of Vue 3 Composition API Proven ability to collaborate with back-end/platform teams to design robust API contracts and manage complex data orchestration Experience deploying and scaling front-end applications in AWS environments Hands-on experience with Vite and modern testing tools (Cypress, Vitest) Solid AdTech domain knowledge, including advertising data models and workflows Upper-Intermediate English proficiency Personal Profile Strong leadership and mentoring skills Excellent communication and collaboration abilities Analytical mindset with a focus on scalability and maintainability

🏢 Summary: Senior Principal Engineer role focused on leading the architectural transformation of a scalable AdTech platform toward a platform-first, API-driven ecosystem. The position combines hands-on TypeScript/Vue.js development with architectural leadership across microservices and serverless environments. Full remote across Europe with responsibility for technical vision, cross-functional leadership, and enterprise stakeholder collaboration. 🗂️ Requirements: 6+ years experience with JavaScript, 6+ years experience with TypeScript, 6+ years experience with Vue.js, 6+ years experience with Node.js, Experience with microservices architecture, Experience with distributed systems integration, Hands-on experience with AWS Lambda or similar serverless technologies, Strong understanding of plugin-based systems and extensibility, Experience customizing and extending existing solutions, Experience in AdTech environments, Knowledge of Vite, Knowledge of Cypress, Knowledge of Vitest, Experience with AWS S3, Experience with AWS CloudFront, Ability to translate business goals into technical solutions, Fluent English 📃 Skills: JavaScript, TypeScript, Vue.js, Node.js, Microservices, AWS, Lambda, S3, CloudFront, Vite, Cypress, Vitest, Serverless, API, Architecture 🏢 Description: Are you an experienced technical leader ready to shape the future of scalable AdTech platforms? We are seeking a Principal Engineer to drive architectural transformation and lead high-impact projects for a Sweden-based industry innovator. This is a senior-level role with full remote flexibility across Europe. At Sigma Software, we partner with global leaders to deliver cutting-edge technology solutions that automate and optimize revenue-focused operations. You will work on strategic initiatives, collaborate with cross-functional teams, and influence technical direction in a fast-paced, evolving domain. Why join us? You’ll have the opportunity to work on globally recognized platforms, contribute to architectural innovation, and enjoy a supportive culture with challenging projects. Customer Our Customer is a Swedish AdTech company that transforms the way publishers and advertisers interact. They provide state-of-the-art self-serve advertising platforms that enable seamless, direct transactions between advertisers and some of the world’s largest publishers. Their mission is to make advertising more accessible, automated, and efficient through innovative technology. Together, we serve globally recognized clients, including TripAdvisor, Bloomberg, The Washington Post, Opera, Dow Jones, etc. Project The project represents a strategic transition to a Platform-First, API-driven architecture. The company is moving away from monolithic, client-specific codebases to a standardized ecosystem. As a Senior TypeScript/Vue.js Developer, you will be the technical visionary for the platforms, ensuring the technology remains high-performing and scalable. Requirements At least 6+ years of hands-on experience in JavaScript / TypeScript, Vue.js, and Node.js Experience in microservices architecture and distributed systems integration Hands-on experience with AWS Lambda or similar serverless technologies Deep understanding of plugin-based systems and extensibility points Proven ability to customize and extend existing solutions without breaking core functionality Experience in AdTech environments with evolving requirements Knowledge of Vite, Cypress, and Vitest for modern development workflows and testing Experience with AWS S3 and CloudFront for scalable storage and content delivery Strong commercial acumen and ability to translate business goals into technical infrastructure Fluent English communication skills for enterprise stakeholder management Will be a plus Experience with other serverless frameworks (e.g., Azure Functions, Google Cloud Functions) Familiarity with enterprise e-commerce platforms Knowledge of performance optimization and security best practices Prior work in media publishing technology solutions Personal Profile Proactive, solution-oriented mindset Strong problem-solving skills and ability to unblock dependencies Comfortable working in fast-paced environments with evolving requirements System-thinking approach — seeing beyond individual tasks to the bigger picture Responsibilities Act as a key technical liaison between business and engineering teams, translating commercial goals into actionable technical solutions Evaluate publisher technical environments and design scalable, maintainable architectures Prepare client-ready solution proposals, including features, integrations, and tools Lead cross-functional delivery teams, including developers, designers, DevOps, and technical PMs Provide architectural oversight throughout the development lifecycle to ensure continuity and quality Manage distributed teams across multiple time zones Mentor engineers, conduct code reviews, and guide technical growth Make architectural decisions at component and plugin levels, balancing trade-offs and communicating choices clearly

🏢 Summary: Senior Node.js Engineer role focused on building and scaling a secure, high-performance FinTech platform used by businesses across Europe. The position involves designing distributed systems, developing backend and frontend components, and working within a distributed agile team using modern cloud and microservices architecture. The offer emphasizes technical leadership, code quality, and collaboration on complex financial solutions. 🗂️ Requirements: 5+ years Back-End development experience, 3+ years TypeScript experience, 4+ years Node.js experience, Experience designing distributed systems, Experience building secure and scalable systems, Strong AWS experience, Frontend development experience, Understanding of microservices architecture, Experience designing and maintaining APIs, Experience with REST and/or GraphQL APIs, Knowledge of DevOps practices, Knowledge of testing best practices, Upper-Intermediate English level 📃 Skills: Node.js, TypeScript, React, AWS, Microservices, REST, GraphQL, JavaScript, ES6, DevOps, API, Testing 🏢 Description: Are you ready to take on a key role in developing cutting-edge financial solutions? We are looking for a Senior Node.js Engineer to join our distributed agile team and work on a highly secure, scalable FinTech platform used by businesses across Europe. We at Sigma Software value innovation, technical excellence, and collaboration. This position offers the opportunity to work with modern technologies such as Node.js, TypeScript, React, AWS, and microservices architecture. You’ll have the chance to work on impactful projects, enjoy flexible working arrangements, and grow your expertise alongside talented professionals. CUSTOMER Our Customer is one of Europe’s fastest-growing FinTech companies, providing a comprehensive payment platform that integrates financial services into its products. Their solutions include account management, virtual cards, bank transfers, and other advanced features. The company is known for its innovative approach to simplifying financial operations for businesses, ensuring security, scalability, and user-centric design. PROJECT The project focuses on building and enhancing a secure, scalable, and user-friendly financial services platform used by businesses across Europe. The team is distributed and agile, with a strong emphasis on engineering best practices and code quality. Key Technologies: Node.js, TypeScript, React, AWS, Microservices, REST, GraphQL. RESPONSIBILITIES Design, develop, and implement large-scale software solutions using Node.js and React Ensure high quality and maintainability of code across all stages of development Collaborate closely with cross-functional teams to gain full context for complex tasks Adhere to engineering best practices, company policies, and client guidelines Provide mentorship, technical guidance, and coaching to less-experienced engineers Advocate for clean code principles, design patterns, and architectural best practices Design and maintain distributed and secure systems, ensuring scalability and performance Build and integrate APIs into the platform Work with AWS services and DevOps practices to ensure reliability and efficiency REQUIREMENTS Over 5 years of experience in Back-End software development At least 3 years of experience with TypeScript Over 4 years of experience working with Node.js Strong experience in designing distributed and secure systems Strong experience working with AWS Good Front-End development skills Good understanding of microservices architectures Experience in designing, building, and maintaining APIs Experience in building and consuming REST and/or GraphQL APIs Familiarity with DevOps practices Good knowledge of testing best practices At least an Upper-Intermediate level of English WILL BE A PLUS Experience with modern JavaScript and ES6 libraries PERSONAL PROFILE Proactive problem-solver with a strong sense of ownership Effective communicator and team collaborator Adaptable to changing priorities and requirements

🏢 Summary: Senior Node.js Engineer role focused on designing and developing a secure, scalable FinTech platform for European businesses. The position involves working in a distributed agile team using modern technologies to build and enhance financial services solutions. The offer emphasizes high-quality engineering practices, microservices architecture, and cloud-based infrastructure. 🗂️ Requirements: 5+ years Back-End development experience, 4+ years Node.js experience, 3+ years TypeScript experience, Experience designing distributed systems, Experience designing secure systems, Strong AWS experience, Front-End development skills, Understanding of microservices architecture, Experience designing and maintaining APIs, Experience with REST or GraphQL APIs, Familiarity with DevOps practices, Knowledge of testing best practices, Upper-Intermediate English level 📃 Skills: Node.js, TypeScript, React, AWS, Microservices, REST, GraphQL, JavaScript, ES6, DevOps, API, Testing 🏢 Description: Are you ready to take on a key role in developing cutting-edge financial solutions? We are looking for a Senior Node.js Engineer to join our distributed agile team and work on a highly secure, scalable FinTech platform used by businesses across Europe. We at Sigma Software value innovation, technical excellence, and collaboration. This position offers the opportunity to work with modern technologies such as Node.js, TypeScript, React, AWS, and microservices architecture. You’ll have the chance to work on impactful projects, enjoy flexible working arrangements, and grow your expertise alongside talented professionals. CUSTOMER Our Customer is one of Europe’s fastest-growing FinTech companies, providing a comprehensive payment platform that integrates financial services into its products. Their solutions include account management, virtual cards, bank transfers, and other advanced features. The company is known for its innovative approach to simplifying financial operations for businesses, ensuring security, scalability, and user-centric design. PROJECT The project focuses on building and enhancing a secure, scalable, and user-friendly financial services platform used by businesses across Europe. The team is distributed and agile, with a strong emphasis on engineering best practices and code quality. Key Technologies: Node.js, TypeScript, React, AWS, Microservices, REST, GraphQL. RESPONSIBILITIES Design, develop, and implement large-scale software solutions using Node.js and React Ensure high quality and maintainability of code across all stages of development Collaborate closely with cross-functional teams to gain full context for complex tasks Adhere to engineering best practices, company policies, and client guidelines Provide mentorship, technical guidance, and coaching to less-experienced engineers Advocate for clean code principles, design patterns, and architectural best practices Design and maintain distributed and secure systems, ensuring scalability and performance Build and integrate APIs into the platform Work with AWS services and DevOps practices to ensure reliability and efficiency REQUIREMENTS Over 5 years of experience in Back-End software development At least 3 years of experience with TypeScript Over 4 years of experience working with Node.js Strong experience in designing distributed and secure systems Strong experience working with AWS Good Front-End development skills Good understanding of microservices architectures Experience in designing, building, and maintaining APIs Experience in building and consuming REST and/or GraphQL APIs Familiarity with DevOps practices Good knowledge of testing best practices At least an Upper-Intermediate level of English WILL BE A PLUS Experience with modern JavaScript and ES6 libraries PERSONAL PROFILE Proactive problem-solver with a strong sense of ownership Effective communicator and team collaborator Adaptable to changing priorities and requirements

🏢 Summary: Senior Front-End Developer role focused on building large-scale, secure, and scalable solutions using React.js and TypeScript within a FinTech environment. The position involves designing distributed systems, developing APIs, and ensuring high-quality standards across the development lifecycle. The role also includes mentoring team members and contributing to architectural and technical decisions. 🗂️ Requirements: 5+ years of front-end development experience, 3+ years of TypeScript experience, 4+ years of React.js experience, Experience designing distributed and secure systems, Understanding of microservices architecture, Experience designing and maintaining APIs, Experience with REST or GraphQL APIs, Experience with AWS cloud services, Knowledge of testing best practices, Upper-Intermediate English proficiency 📃 Skills: React, TypeScript, JavaScript, REST, GraphQL, AWS, Microservices, APIs, Docker, Kubernetes, CI/CD 🏢 Description: Ready to take your front-end expertise to the next level? At Sigma Software, we’re looking for a Senior Front-End Developer with strong React.js expertise who thrives on crafting exceptional user experiences and delivering high-quality, scalable solutions. Joining Sigma Software means becoming part of a global team that values your ideas, supports your growth, and empowers you to make an impact. We believe in combining cutting-edge technologies with a culture of collaboration and continuous improvement. Customer Our client has rapidly become one of Europe’s most swiftly expanding FinTech companies. They oversee all aspects of financial operations, from generating virtual cards to facilitating wire transfers and maintaining customer account balances. As a payment institution, our client provides a platform that integrates financial services into its product, offering features such as account management, card payments, bank transfers, and additional services. Responsibilities Design and implement large-scale software solutions and components, primarily using React.js and TypeScript Maintain high-quality standards throughout development, testing, and deployment phases Collaborate closely with cross-functional teams to understand requirements and deliver optimal solutions Mentor and guide less-experienced engineers, fostering knowledge sharing and skill development Apply clean code principles, design patterns, and best practices in all development work Ensure system security and scalability in distributed architectures Participate in code reviews and continuous improvement initiatives Requirements 5+ years of experience in front-end software development 3+ years of experience with TypeScript 4+ years of experience working with React.js Strong expertise in designing distributed and secure systems Solid understanding of microservices architecture Experience in designing, building, and maintaining APIs Proficiency in building and consuming REST and/or GraphQL APIs Experience working with AWS cloud services Knowledge of testing best practices Upper-Intermediate or higher English proficiency Would be a plus Familiarity with DevOps practices Experience with CI/CD pipelines and automation tools Knowledge of containerization (Docker, Kubernetes) Exposure to financial services or payment systems Understanding of regulatory compliance in FinTech Personal Profile Strong analytical and problem-solving skills Excellent communication and team collaboration abilities Proactive approach to learning and adopting new technologies Leadership mindset with mentoring capabilities Attention to detail and commitment to quality

🏢 Summary: Senior Front-End Developer role focused on building scalable, secure fintech solutions using React.js and TypeScript. The position involves designing large-scale distributed systems, developing and integrating APIs, and ensuring high-quality standards across the development lifecycle. The role also includes mentoring engineers and contributing to architectural decisions in a cloud-based environment. 🗂️ Requirements: 5+ years of front-end development experience, 3+ years of experience with TypeScript, 4+ years of experience with React.js, Experience designing distributed and secure systems, Understanding of microservices architecture, Experience designing and maintaining APIs, Experience building and consuming REST or GraphQL APIs, Experience with AWS cloud services, Knowledge of testing best practices, Upper-Intermediate English proficiency 📃 Skills: React.js, TypeScript, JavaScript, REST, GraphQL, AWS, Microservices, APIs, Docker, Kubernetes, CI/CD 🏢 Description: Ready to take your front-end expertise to the next level? At Sigma Software, we’re looking for a Senior Front-End Developer with strong React.js expertise who thrives on crafting exceptional user experiences and delivering high-quality, scalable solutions. Joining Sigma Software means becoming part of a global team that values your ideas, supports your growth, and empowers you to make an impact. We believe in combining cutting-edge technologies with a culture of collaboration and continuous improvement. Customer Our client has rapidly become one of Europe’s most swiftly expanding FinTech companies. They oversee all aspects of financial operations, from generating virtual cards to facilitating wire transfers and maintaining customer account balances. As a payment institution, our client provides a platform that integrates financial services into its product, offering features such as account management, card payments, bank transfers, and additional services. Responsibilities Design and implement large-scale software solutions and components, primarily using React.js and TypeScript Maintain high-quality standards throughout development, testing, and deployment phases Collaborate closely with cross-functional teams to understand requirements and deliver optimal solutions Mentor and guide less-experienced engineers, fostering knowledge sharing and skill development Apply clean code principles, design patterns, and best practices in all development work Ensure system security and scalability in distributed architectures Participate in code reviews and continuous improvement initiatives Requirements 5+ years of experience in front-end software development 3+ years of experience with TypeScript 4+ years of experience working with React.js Strong expertise in designing distributed and secure systems Solid understanding of microservices architecture Experience in designing, building, and maintaining APIs Proficiency in building and consuming REST and/or GraphQL APIs Experience working with AWS cloud services Knowledge of testing best practices Upper-Intermediate or higher English proficiency Would be a plus Familiarity with DevOps practices Experience with CI/CD pipelines and automation tools Knowledge of containerization (Docker, Kubernetes) Exposure to financial services or payment systems Understanding of regulatory compliance in FinTech Personal Profile Strong analytical and problem-solving skills Excellent communication and team collaboration abilities Proactive approach to learning and adopting new technologies Leadership mindset with mentoring capabilities Attention to detail and commitment to quality

🏢 Summary: B2B contract role for a Mid/Senior Node.js Developer focused on building and maintaining backend systems such as SaaS platforms, cloud-native applications, microservices, and event-driven architectures. The position involves architectural decision-making, backend development, and close collaboration with QA and DevOps in international projects. Candidates will work with modern cloud environments and have real impact on system design and product development. 🗂️ Requirements: 4+ years of backend development experience, Strong knowledge of Node.js, Experience with TypeScript or JavaScript, Experience with SQL databases, Experience with NoSQL databases, Understanding of microservices architecture, Understanding of serverless architecture, Understanding of event-driven systems, Hands-on experience with GCP, AWS, or Azure, Ability to write clean and maintainable code, Experience with unit and integration testing, English level minimum B2 📃 Skills: Node.js, TypeScript, JavaScript, SQL, NoSQL, GCP, AWS, Azure, REST, Docker, Microservices, Serverless, Testing 🏢 Description: We are a software house delivering long-term projects for international clients , and we are looking for Mid / Senior Node.js Developers to join our team on a B2B contract . You will work on various backend-focused projects , such as SaaS platforms, cloud-native systems, microservices, and event-driven architectures. We match projects to your experience and technical preferences, and you will have a real impact on architecture and product development. Responsibilities design, develop, and maintain backend services using Node.js (TypeScript / JavaScript) implement new features and improve existing functionalities participate in technical and architectural decision-making refactor and optimize key components of the system ensure code quality through clean code practices and testing collaborate closely with developers, QA, and DevOps engineers Requirements 4+ years of experience in backend development strong knowledge of Node.js (TypeScript / JavaScript) experience with SQL and NoSQL databases good understanding of cloud-based architectures (microservices, serverless, event-driven systems) hands-on experience with at least one cloud provider ( GCP, AWS, or Azure ) ability to write clean, well-structured, and maintainable code proactive mindset and willingness to grow technically good communication skills and English level min. B2B Example Tech Stack (depends on the project) Node.js / TypeScript Cloud platforms: GCP, Azure or AWS REST APIs & asynchronous communication SQL & NoSQL databases Docker Unit and integration testing

🏢 Summary: Opportunity to architect and build a brand-new, high-scale, event-driven backend product from scratch using Node.js and TypeScript on AWS. The role focuses on designing resilient distributed systems, owning features end-to-end, and shaping technical direction in a high-growth environment. You will drive scalable architecture, ensure high code quality, and deploy production-ready services for global workloads. 🗂️ Requirements: 5+ years experience with Node.js and TypeScript in production environments, Advanced proficiency with AWS (Lambda, ECS, S3, RDS), Strong expertise in system design and scalability, Experience designing event-driven architectures, Experience with modern testing frameworks (Vitest, Jest, Playwright), Ability to build and deploy distributed systems, Experience with SQL and NoSQL databases, Knowledge of CI/CD practices using Docker and Kubernetes, Professional English proficiency 📃 Skills: Node.js, TypeScript, AWS, Lambda, ECS, S3, RDS, Vitest, Jest, Playwright, Docker, Kubernetes, SQL, NoSQL, Go, React, CI/CD 🏢 Description: We are looking for a high-impact engineer to architect a brand-new product from the ground up. In this role, you will bypass maintenance of legacy systems to design and develop high-scale, event-driven backend infrastructures. Operating at the intersection of technical rigor and rapid product evolution, you will thrive in an environment of high ambiguity where your architectural decisions define the roadmap. Core Responsibilities Architect and scale mission-critical backend services using Node.js and TypeScript . Design and implement high-performance APIs and sophisticated event-driven architectures on AWS . Engineer resilient, distributed systems capable of managing intensive global workloads. Own feature development end-to-end, navigating the lifecycle from initial design to production deployment. Partner closely with product and cross-functional engineering leads to drive technical innovation. Mentor the engineering squad and champion elite standards in code quality, security, and testing. Adapt and pivot technical strategies as the product scales and new challenges emerge. Technical Requirements 5+ years of hands-on experience deploying Node.js and TypeScript in high-stakes production environments. Advanced proficiency with the AWS ecosystem, including Lambda, ECS, S3, and RDS. Deep expertise in system design, scalability, and modern event-driven paradigms. Experience utilizing modern testing frameworks such as Vitest, Jest, or Playwright to ensure zero-defect deployments. Elite problem-solving skills with the ability to operate autonomously in a fast-moving hub. Professional fluency in English with a track record of driving cross-functional alignment. A high-velocity mindset suited for a dynamic, high-growth engineering culture. Additional Assets Hands-on experience with Go . Background in distributed systems or complex event-driven platforms. Experience integrating LLMs or modern AI tooling into production workflows. Practical knowledge of React or modern frontend frameworks. Deep understanding of SQL/NoSQL database optimization and CI/CD best practices via Docker and Kubernetes. The Offer Competitive compensation aligned with the top-tier Kraków tech market (UoP or B2B options). Flexible hybrid work model based in the heart of Kraków. Radical ownership and the unique opportunity to shape a global product from day one. Collaborative, English-speaking engineering environment within a stable, profitable firm with a long-term vision.