Backend Developer (Node.JS)

🏢 Summary: 12-month B2B contract for a Frontend Developer to build and enhance mobile and web features for a flagship cashback/loyalty application in a fast-paced Agile environment. The role focuses on React Native and React development for customer-facing apps and requires collaboration with US-based teams during CET afternoon hours. 🗂️ Requirements: 5+ years experience with React Native and React, Experience with GraphQL, Experience building customer-facing mobile and web apps, Experience with apps published on iOS and Android stores, Experience working in Agile teams, Availability to work 2pm–10pm CET 📃 Skills: React, ReactNative, GraphQL, TypeScript, Node.js, PostgreSQL, GCP, Redis, Docker, Kafka, Apollo, CI/CD 🏢 Description: Our client - a fast-growing US-based fintech - is looking to hire 2 strong Frontend Developers to help on an initial 12-month B2B contract, to work remotely. You will be working in an Agile team, dedicated to working on new features and products related to the companies flagship Cashback / Loyalty application. This will be a dynamic and fast-paced environment, working on both mobile and web apps. You must be comfortable working from 2pm-10pm CET, in order to have full consistency with the US teams. Requirements: 5+ years of experience working with React Native / React Familiarity with GraphQL Strong experience working with customer-facing mobile and web apps (B2C), that are live on iOS / Android stores Strong ability to work in agile teams, with good communication skills Experience with the following is not necessary , but are part of the wider tech stack and so any supplementary knowledge could be helpful: Typescript, Node.js, PostgreSQL, GCP, Redis, Docker, Apache Kafka, Apollo GraphQL, CI/CD tools

🏢 Summary: B2B contract role for a Backend Developer to build and maintain scalable microservices in an Ad Tech platform using Node.js, Nest.js, and TypeScript. The position focuses on backend architecture, performance, and integration within a fully remote team based in Romania. Initial 6-month project with possible extensions. 🗂️ Requirements: Strong experience with Node.js, Strong experience with Nest.js, Strong experience with TypeScript, Proven experience building scalable backend microservices, Experience with AWS Lambda or serverless frameworks, Experience working in agile teams 📃 Skills: Node.js, Nest.js, TypeScript, AWS, Lambda, Serverless, Microservices, REST, CI/CD, Git 🏢 Description: Backend Developer (Node.js) – Integration & Backend Team Work model : fully remote in Romania Assignment type : B2B Project length : 6 months + extensions. Project language : English. Industry : Ad Tech industry About the Role We are looking for a Backend Developer to join our Integration & Backend team. You will build robust, scalable microservices that power our platform, using Node.js, Nest.js, and TypeScript. Responsibilities Develop and maintain backend microservices using Node.js and Nest.js. Ensure scalability, performance, and reliability across backend systems. Collaborate with frontend teams and product owners to deliver features. Contribute to code reviews, testing, and continuous integration. Support the design and improvement of backend architecture. Key Requirements Strong experience with Node.js, Nest.js, and TypeScript . Proven track record in building scalable backend microservices. Familiarity with serverless frameworks such as AWS Lambda . Experience working in agile teams. Previous experience with SaaS, e-commerce, or Adtech is meritorious.

🏢 Summary: Full-time Backend Developer role focused on building and maintaining scalable Node.js and TypeScript applications for US clients across various industries, including MVP-stage products. The position involves designing backend architecture, working with SQL/NoSQL databases, and collaborating in Scrum teams in a flexible, remote-first environment. The offer includes long-term cooperation and participation in diverse, technically challenging projects. 🗂️ Requirements: 2+ years commercial experience in Node.js, Experience with Node.js frameworks (Express.js, NestJS or similar), Strong proficiency in TypeScript, Experience with SQL databases, Experience with NoSQL databases, Knowledge of SOLID and KISS principles, Knowledge of design and architecture patterns, Experience with Docker, Experience with GitHub Actions, Basic experience with AWS services, Ability to use ORM or query builders (e.g. Prisma, Knex), English level B2, Polish level C1 📃 Skills: Node.js, TypeScript, JavaScript, Express, NestJS, Fastify, SQL, NoSQL, Prisma, Knex, Docker, AWS, GitHub, GitHubActions, React 🏢 Description: We are looking for skillful Backend Developers to join one of our teams working with US clients - referrals from the high-end American IT market. Our tech stack is built around React, Node.js and TypeScript. We are working with well-established companies and sometimes startups in their early stages (MVPs), which makes the job full of diversity and exciting challenges while crafting cutting-edge solutions. Enjoy the flexibility of working within the Polish time zone and collaborate with clients from diverse industries such as FinTech, SportsTech, MedTech, and many others. Required skills: 2+ years of commercial experience in Node.js, SQL and NoSQL DBs, knowledge of JS frameworks (e.g Express.js, NestJS), experience in TypeScript, SOLID and KISS, knowledge about design and architecture patterns, know how and why Docker and GitHub Actions works, basic usage of AWS services, English B2, Polish C1 Offer: B2B/UZL, paid days off, 100% remote (or hybrid/onsite - as you prefer), Polish time zone, flexible hours, full-time position, long-term contract, Scrum Teams Perks and Benefits: Budgets for self-development, integrations, healthcare & sport activities, Mentoring Program, Individual Career Path, Paid Time Off, Paid Health Break & more Tools you'll use: Apple MacBook Pro, Slack, GSuite, GitHub, Jira, Coda, FigJam Your future tasks and duties: Writing readable and easy-to-maintain JS/TS code with OOP flavor Writing documentation for delivered code Code review of other developers in the team Direct involvement with the design and modification of basic DB structures Propose improvements and share proactive ideas/solutions with the team to enhance the team's work processes Share insights with the team to diagnose issues and focus on solutions Actively participate in project discussions Listen to the client's needs and, after consulting the team, suggest solutions Support less experienced team members About you - Tech skills & Experience: 2+ years of commercial experience in Node.js Good experience with at least one Node.js backend framework (e.g. Express.js, NestJS, Fastify, etc) - you know most of its basic APIs/features, worked on at least 1-2 projects involving such technologies Strong proficiency in TypeScript. You have practical experience with static typing, advanced types, and configuring TS compilers, treating it as your primary language to build robust and type-safe backend applications Potentially worked with NoSQL databases and/or in-memory databases and utilized them as a data store Worked with SQL databases (integration-wise and as a basic design skill) with ORM or query builder tool (ie. Prisma, Knex) Knows the basics of building AI applications (RAG, Agents, etc.) Use AI effectively in their work About you - Soft Skills: English level B2 to cooperate with American clients Polish level C1 to communicate easily within the team Open-minded to new challenges (e.g. different frameworks) Understand the significance of MVP and prioritize the pursuit of excellence and high-quality outcomes, even amid tight project timelines. Communicate with the team to efficiently translate business complexities (user stories/tasks) into solutions (results/estimations) Staying on top with trends/news, sharing them, teaching others and aiming for the best quality solutions Strong problem-solving abilities to diagnose issues, suggest solutions, and make decisions based on project requirements Nice to have: Worked in Agile/Scrum on a daily basis consisting of people with similar skills and monitoring code quality on a daily basis Basic experience with AWS - used some services in specific cases Basic experience with Docker - know how to prepare and debug the environment and connect things up to work locally Worked in the very beginning of the product development/creation stage Understand the significance of MVP and aim to deliver top-notch results, even amid tight project timelines Recruitment process: CV Review Phone call with our Recruiter (15min) Soft-skills interview with our Recruiter (1h) Technical interview with our Specialists (2h) Decision and feedback 🥳 Meaningful projects, top-notch experts and value-driven workplace Sound good? Apply now!

🏢 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: Full-Stack / Backend Developer role focused on building and maintaining scalable applications and REST APIs that support client products. The position involves developing new integrations, enhancing existing backend and frontend systems, and improving platform performance and reliability. You will contribute to architecture improvements and work within a cloud-based environment. 🗂️ Requirements: Minimum 3 years commercial experience, Experience with Java, Experience with Spring Boot, Experience with AWS, Experience with MongoDB, Experience with PostgreSQL, Experience with React.js, Experience designing REST APIs, Knowledge of backend architecture, Experience with cloud environments, Understanding of clean code principles, Experience working in Agile environment 📃 Skills: Java, SpringBoot, AWS, MongoDB, PostgreSQL, React, REST, Agile, Cloud, Architecture 🏢 Description: We are looking for an experienced Full-Stack / Backend Developer to join our team and help build scalable applications and APIs supporting our clients’ products. You will work on both backend and frontend solutions, contributing to product development, system improvements, and ongoing platform stability. Your Responsibilities Develop new APIs to support client integrations and business features. Maintain and enhance existing backend and frontend applications. Fix bugs and improve application performance and reliability. Upgrade and support operational aspects of the platform. Identify opportunities to improve product quality, architecture, and development processes. Collaborate with developers, product teams, and stakeholders to deliver high-quality solutions. Participate in code reviews and contribute to best engineering practices. Required Skills Minimum 3 years of commercial experience with: Java Spring Boot AWS MongoDB PostgreSQL React.js Experience designing and developing REST APIs. Knowledge of backend architecture and modern web applications. Experience working with cloud-based environments (AWS). Understanding of software development best practices and clean code principles. Ability to work in an Agile development environment.

🏢 Summary: Senior Backend Node.js Developer role focused on building and scaling an event-driven microservices trading platform. The position involves end-to-end development within a distributed architecture, ensuring high performance, scalability, and code quality. Fully remote B2B contract with overlap with NYC hours. 🗂️ Requirements: 4+ years web application development experience, Expert knowledge of Node.js, Expert knowledge of TypeScript, Experience with distributed systems architecture, Experience with Apache Kafka, Experience with Redis, Experience with Kubernetes, Experience with MongoDB, Experience with automated unit testing and TDD, Strong understanding of performance optimization and computational complexity, Knowledge of algorithms and design patterns, Broad knowledge of web technologies 📃 Skills: Node.js, TypeScript, Kafka, Redis, Kubernetes, MongoDB, Microservices, TDD, Algorithms, DesignPatterns, Web 🏢 Description: We are looking for a performance-driven backend Senior Node.js Developer who can help us bring our client's trading solutions to the next level of functionality, scalability, and user experience. They are actively developing a new event-driven microservices architecture to form a foundational platform for delivering new trading applications. You will be responsible for delivering software end-to-end , from liaising with product managers and designers, to coordinating across international development teams on engineering and architecture to working with QA and DevOps teams - all ultimately to deliver a quality, innovative product to the traders and investors who depend on the platform every day. Requirements: Fluent English language [both written and spoken] Education: at least Bachelor's Degree, preferably in Computer Science 4+ years' professional web application development experience Expert-level Node.js and TypeScript knowledge, and curiosity to learn more Broad knowledge of web platform and technologies Superior analytical and problem-solving ability Effective communication skills to work with different teams across an international company Experience with modern distributed systems and infrastructure technologies, including Apache Kafka, Redis, Kubernetes, and MongoDB Automated unit testing and test-driven development Robust understanding of performance issues, computational complexity, and code optimization. Familiarity and implementation of industry-standard algorithms and design patterns Proactive and team player who can deliver in a high-pressure demanding environment Nest.js – nice to have Offer details: 100% remote job preferrably at least 4-5 hours overlap with NYC working hours B2B contract rate up to 55 USD/h net

🏢 Summary: Remote Senior Backend Node.js Developer role focused on building and scaling an event-driven microservices trading platform. The position involves end-to-end development, collaborating across product, QA, and DevOps to deliver high-performance, scalable trading solutions. B2B contract with overlap required with NYC working hours. 🗂️ Requirements: Bachelor’s Degree in Computer Science or related field, 3-5 years professional web application development experience, Expert-level Node.js knowledge, Expert-level TypeScript knowledge, Experience with distributed systems, Experience with Apache Kafka, Redis, Kubernetes, MongoDB, Experience with automated unit testing and TDD, Strong understanding of performance optimization and computational complexity, Knowledge of algorithms and design patterns, Fluent English (written and spoken) 📃 Skills: Node.js, TypeScript, Kafka, Redis, Kubernetes, MongoDB, Microservices, TDD, Algorithms, DesignPatterns, Web, DistributedSystems 🏢 Description: We are looking for a performance-driven backend Senior Node.js Developer who can help us bring our client's trading solutions to the next level of functionality, scalability, and user experience. They are actively developing a new event-driven microservices architecture to form a foundational platform for delivering new trading applications. You will be responsible for delivering software end-to-end , from liaising with product managers and designers, to coordinating across international development teams on engineering and architecture to working with QA and DevOps teams - all ultimately to deliver a quality, innovative product to the traders and investors who depend on the platform every day. Requirements: Fluent English language [both written and spoken] Education: at least Bachelor's Degree, preferably in Computer Science 3-5 years' professional web application development experience Expert-level Node.js and TypeScript knowledge, and curiosity to learn more Broad knowledge of web platform and technologies Superior analytical and problem-solving ability Effective communication skills to work with different teams across an international company Experience with modern distributed systems and infrastructure technologies, including Apache Kafka, Redis, Kubernetes, and MongoDB Automated unit testing and test-driven development Robust understanding of performance issues, computational complexity, and code optimization. Familiarity and implementation of industry-standard algorithms and design patterns Proactive and team player who can deliver in a high-pressure demanding environment Nest.js – nice to have Offer details: 100% remote job preferrably at least 4-5 hours overlap with NYC working hours B2B contract rate up to 50 USD/h net Don't hesitate and apply now!

🏢 Summary: Fullstack Developer role focused on building and maintaining backend services in Node.js and frontend applications in React/Next.js, with occasional involvement in smart contract development. The position involves working with databases, APIs, and collaborating across backend and blockchain teams in an onsite environment. The offer is targeted at senior-level engineers with strong production experience. 🗂️ Requirements: Strong Node.js/NestJS backend experience, Minimum 5 years of backend development experience, Minimum 2 years maintaining production applications, Strong React and TypeScript skills, Experience with database and API integration, Ability to work onsite in Warsaw (100%), English level B2 or higher 📃 Skills: Node.js, NestJS, Express, React, Next.js, TypeScript, PostgreSQL, MongoDB, API, EVM, SVM 🏢 Description: About BlockyDevs We build end-to-end applications combining fintech-grade reliability with Web3 innovation. Your Role As a Fullstack Developer, you’ll primarily work with Node.js on the backend, React on the frontend, and occasionally contribute to smart contract development. Responsibilities Develop backend services with *Node.js (NestJS/Express)** Build frontend apps with *React/Next.js + TypeScript** Work with databases (PostgreSQL, MongoDB) and APIs Occasionally contribute to smart contracts (EVM/SVM) Collaborate with design, backend, and blockchain teams Requirements Strong backend skills in Node.js/NestJS At least 5 years of experience in backend applications At least 2 years of experience in maintaining production applications Solid frontend skills in React + TypeScript Database and API integration knowledge Experience mentoring mid/junior developers English at least B2 level Ability to work 100% onsite from our office near Metro Plac Wilsona, Warsaw Nice-to-have Microservices and cloud deployment experience Web3 integrations knowledge Rates (B2B/Freelance) Senior: 120 - 180 PLN/h Recruitment Process 1. Intro Call (30 min) – Quick chat about your experience, expectations, and our projects. 2. Technical Interview / Task – Backend (Node.js) and frontend (React) focus, with some discussion of smart contracts. 3. Final Meeting – Culture/fit + project discussion. 4. Offer – Fast decision if it’s a match. 5. Process usually takes 2–3 weeks . 6. Feedback after each stage within a few days

🏢 Summary: Fullstack Developer role in a long-term, fully remote project focused on building and maintaining a global digital product supporting retail and service operations. The position covers end-to-end product ownership, including development of micro frontends and microservices, cloud deployment, and production support. It offers hands-on work in a modern, scalable, event-driven architecture. 🗂️ Requirements: Strong backend development experience with Java or Kotlin, Solid frontend development experience with React or similar framework, Experience working in AWS cloud environments, Practical experience with microservices architecture, Experience with CI/CD pipelines, Ability to work in trunk-based development setup, Experience with event-driven systems such as Kafka, Familiarity with AI-assisted and agentic development workflows 📃 Skills: Java, Kotlin, React, AWS, Kubernetes, Kafka, GitLab, CI/CD, Microservices 🏢 Description: PROJECT DETAILS: Workload: Full-time Contract: B2B Start : ASAP Model: 100% remote Business Travels: Occasionally BYOD - bring your own device Security check is required as part of the process Initial 6-month contract , with a project planned for at least 3 years Join our project and help build a global digital product used by retailers and service advisors around the world. We are looking for an experienced Fullstack Developer to join the team with a product that supports resale operations and service processes by delivering accurate, optimised information to employees across the dealer network. This is a great opportunity for someone who enjoys working across the full application lifecycle, from development to production , and wants to have a real impact on a modern, business-critical solution. About the role You will be part of a team that owns the product end-to-end — from building new functionality to deploying and maintaining it in production. This is a hands-on engineering role where you will work closely with other developers, contribute to a shared codebase, and help ensure the product remains stable, scalable, and high-quality. You will play an active role in shaping and improving the system. What you will work on Developing and maintaining micro frontends and microservices Improving system performance, stability, and scalability Integrating the platform with internal and external services Continuously improving code quality and development practices Contributing throughout the full lifecycle of the application, including production deployment What we are looking for Strong experience in backend development using Java/Kotlin Solid understanding of frontend development with React or a similar framework Experience working in cloud environments , preferably AWS Practical experience with microservices architecture Experience with CI/CD pipelines and modern software development practices Ability to work in a trunk-based development setup Experience working with event-driven systems , such as Kafka Strong familiarity with AI-assisted and agentic workflows as part of everyday software development Tech stack Frontend: React, micro frontends Backend: Kotlin & Java, microservices Infrastructure: AWS, Kubernetes CI/CD: GitLab Pipelines Messaging: Kafka

🏢 Summary: Backend Engineer role focused on designing and scaling real-time, cloud-based systems and APIs for an AI-powered consumer product. The position involves building reliable backend services, data pipelines, and infrastructure on AWS within a high-performing engineering team. You will collaborate with mobile and AI teams to deliver low-latency, scalable, and secure user experiences. 🗂️ Requirements: 2+ years backend development experience with Node.js and TypeScript, Strong knowledge of PostgreSQL including schema design and query optimization, Experience with Redis for caching and queue management, Hands-on experience with AWS services (EC2, RDS, Lambda, ECS, S3), Strong REST API design skills and real-time communication patterns, Understanding of scalability, concurrency, and distributed systems, Experience with Docker, Git workflows, and CI/CD automation, Knowledge of backend security and performance best practices 📃 Skills: Node.js, TypeScript, PostgreSQL, Redis, AWS, EC2, RDS, Lambda, ECS, S3, REST, WebSockets, SSE, Docker, Git, CICD 🏢 Description: Backend Engineer – Node.js, TypeScript, AWS For our client, a fast-growing team building a next-generation AI-powered consumer product, we are looking for an experienced Backend Engineer to help scale the systems powering real-time experiences, cloud synchronization, and intelligent APIs. This is not a founding role, but it is a highly impactful engineering position within a small, high-performing team focused on building world-class consumer technology products. About the role You will be responsible for designing, building, and scaling backend systems that support core product functionality — from real-time data pipelines to reliable cloud infrastructure and low-latency APIs. You’ll work closely with mobile and AI teams to deliver fast, scalable, and highly reliable user experiences. Responsibilities Backend Development Design and build RESTful APIs using Node.js and TypeScript (Express.js or Nest.js) Architect and maintain PostgreSQL databases, including schema design and query optimization Implement background jobs and queue systems using Redis for ingestion, summarization, and notifications Build and maintain caching layers (Redis, CDN, HTTP cache) to ensure low-latency performance Implement authentication, authorization, and data privacy best practices Add real-time capabilities using WebSockets and Server-Sent Events Build observability into services through logging, metrics, and tracing Deploy and manage backend services on AWS (EC2, ECS, RDS, S3, Lambda) Systems & Architecture Design clean, scalable, and maintainable service architectures Plan and execute safe database migrations and schema evolution strategies Ensure consistency and reliability across distributed systems Optimize system performance across I/O, CPU, and memory bottlenecks Build and maintain CI/CD pipelines and release automation workflows Contribute to infrastructure reliability, scalability, monitoring, and cost optimization Quality & Security Write unit, integration, and contract tests with clear quality standards Enforce linting, type safety, and static analysis within CI pipelines Conduct security reviews and dependency audits while following least-privilege principles Clearly document services, APIs, and important architectural trade-offs Requirements Must-have 2+ years of backend development experience with Node.js and TypeScript Strong understanding of PostgreSQL, including schema design, indexing, and query optimization Experience working with Redis for caching and queue management Hands-on experience with AWS services such as EC2, RDS, Lambda, ECS, and S3 Strong API design skills, including REST and real-time communication patterns Solid understanding of scalability, concurrency, and distributed systems Experience with Docker, Git workflows, and CI/CD automation Familiarity with security and backend performance best practices Nice to have Experience with GraphQL or gRPC Exposure to event-driven architectures or microservices Familiarity with observability tools such as OpenTelemetry, CloudWatch, or Sentry Experience building high-traffic consumer applications Example stack Backend: Node.js, TypeScript (Express.js / Nest.js), PostgreSQL, Redis Cloud: AWS (EC2, RDS, Lambda, ECS, S3, CloudWatch) Infrastructure: Docker, GitHub Actions, CI/CD