Backend Software Engineer | Node.js | Remote

Join Our Team as a Junior Backend Engineer!We are seeking a passionate Junior Backend Engineer to be part of our innovative team in Warsaw. At Bolt, our engineering teams tackle unique challenges, including sophisticated algorithms for demand forecasting, real-time pricing optimization, route planning, fraud prevention, distributed systems, and much more.About BoltWith more than 200 million customers across over 50 countries, Bolt stands as one of the fastest-growing tech enterprises in Europe and Africa. Our success is driven by our dedicated team members.We are committed to fostering an inclusive atmosphere where everyone feels valued, irrespective of race, color, religion, gender identity, sexual orientation, nationality, age, or disability. Our ultimate vision is to transform cities for people, not cars, and we invite you to help us realize this mission!Role OverviewAs a Junior Backend Engineer, you will play a crucial role in architecting, designing, developing, and deploying our expanding backend systems. Your primary programming will involve Node.js and TypeScript (prior experience with Node.js is not required).You will work closely with key internal stakeholders to design scalable backend systems and APIs that effectively meet their requirements.

Teltonika Networks is looking for a Junior Backend Software Engineer to join the team in Warsaw, Masovian Voivodeship, Poland. The company develops networking equipment for industrial and enterprise use, including routers, switches, gateways, and modems. Teltonika’s technology supports clients in sectors such as Industry 4.0, Smart City, and Green Energy. For more details on their products, visit Teltonika Products. Role overview This position involves hands-on work with embedded Linux software and API frameworks for IoT devices. The team is international and values collaboration to solve technical challenges. The role is well suited to early-career engineers who want to deepen their technical skills while working on real-world projects. Main responsibilities Design, implement, and maintain embedded Linux software for IoT hardware. Develop and support an API framework used by multiple R&D teams. Analyze and integrate new technologies into existing systems. Collaborate with colleagues from different countries to address complex problems. Requirements At least 1 year of experience programming in C. Minimum 1 year working with APIs. Proficient in Shell and Python scripting. Familiarity with Git version control. Experience working with Linux-based systems. Strong English communication skills, both written and spoken. Preferred qualifications Technical degree in a relevant field. Understanding of computer networking concepts. Experience with Lua programming. Knowledge of OpenWrt. Benefits Opportunities for growth within a growing company. Work on ambitious projects focused on industrial networking devices. Private medical care (Medicover Premium) and Multisport card. Hybrid work model with flexible arrangements. Extra day off for your birthday. Team-building activities to support collaboration.

About Our Team At SumUp, we provide a comprehensive Point-of-Sale (POS) solution designed to empower businesses such as cafes, shops, bars, and salons to streamline operations and foster growth. Our platform encompasses a variety of features including product catalogs, inventory management, business analytics, compliance assistance, and loyalty programs. The Fiscalization team is dedicated to ensuring compliance in countries like Italy, Sweden, Norway, Belgium, and Austria, among others. We are also pioneering the integration with third-party services for fiscalizing receipts. As a Senior Backend Engineer, you will work alongside a vibrant, cross-functional team comprising Product Managers, Designers, Engineering Managers, and fellow engineers. Your Role In this position, you will develop secure backend systems that ensure SumUp's POS products are compliant across various countries on our roadmap. You will collaborate with the Fiscalization squad to devise unique solutions tailored to the challenges in each market. We are looking for a developer who values user-centric design, precision, and seamless collaboration. You will excel in a structured communication environment and thrive in a cross-functional team. This is a B2B role based in Warsaw. Key Responsibilities Design and maintain fiscal compliance solutions to support SumUp's expansion across Italy, Sweden, Norway, Belgium, Austria, and other European markets. Develop integrations with third-party services for receipt fiscalization and regulatory reporting. Navigate SumUp's intricate POS ecosystem and familiarize yourself with fiscalization frameworks across multiple jurisdictions. Work collaboratively with team members and stakeholders distributed across 5+ cities in a hybrid working model. You Will Succeed in This Role If You Have: 5+ years of experience in backend engineering with expertise in Java and/or Kotlin. A solid understanding of system architecture, design principles, data modeling, and API development. Hands-on experience with distributed and fault-tolerant systems. Proficiency in AWS and Kubernetes. Strong knowledge of Kafka, PostgreSQL, and CQRS.

About the RoleJoin Logz.io as a Backend Software Engineer and be part of a dynamic team that is reshaping the observability landscape. In this role, you will design and develop robust backend systems that scale effectively, ensuring seamless integration and exceptional performance.Key ResponsibilitiesDevelop and maintain scalable backend services and APIs.Collaborate with cross-functional teams to define, design, and ship new features.Troubleshoot and optimize existing systems for performance and scalability.Participate in code reviews and contribute to team knowledge sharing.

About the TeamJoin the Sell Online Tribe, a dynamic group that empowers merchants to establish their presence online. We create innovative tools that enable millions of entrepreneurs, from barbers to bakers, to market their products and services effortlessly. Our core focus lies in the Online Store and Bookings products, which form the backbone of SumUp’s ecosystem, allowing merchants to manage appointments, highlight their offerings, and process payments—all from their mobile devices.We are a collaborative, cross-functional team of Product Managers, Designers, and Engineers dedicated to delivering exceptional mobile experiences. As a part of this team, you will play a crucial role in expanding into new sectors, bridging the gap between web and mobile, and making digital selling seamless for small businesses worldwide.About the RoleAs a Senior Backend Engineer, you will be instrumental in enhancing SumUp's major merchant-facing online products within the Bifrost team. You will contribute to the development and scaling of key products such as Payment Links, Virtual Terminal, and Unified Gift Cards, while also working on integration solutions that are vital for numerous other SumUp offerings.We are looking for a developer who prioritizes reliability, teamwork, and continuous growth. Your backend expertise will thrive in a high-impact environment where your contributions directly influence merchant success and team scalability.What You’ll DoEnsure scalability and continuous growth of high-priority online products at SumUpDrive the implementation, development, and integration of Online Checkouts across SumUpEngage actively in planning and review sessions at quarterly and sprint levels, providing constructive feedback and estimationsMonitor existing services, applying necessary fixes to maintain platform reliabilityDevelop new features with maintainable and testable codeEnhance application performance for scalabilityParticipate in code reviews to uphold high coding standardsYou Will Excel in This Role If:You have 5+ years of experience in backend engineering with GolangYou possess a robust understanding of fundamental system architecture, design principles, data modeling, and API designYou have substantial experience with distributed and fault-tolerant systemsYou have a passion for delivering high-quality software solutions

Waymo is pioneering the future of mobility with its cutting-edge autonomous driving technology. Established in 2009 as the Google Self-Driving Car Project, our mission is to become the world’s most trusted driver. Our flagship product, the Waymo Driver—The World’s Most Experienced Driver™—aims to revolutionize access to transportation while drastically reducing road traffic fatalities. The Waymo Driver powers our fully autonomous ride-hailing service and is compatible with various vehicle platforms and applications. With over ten million rider-only trips completed and vast experience from driving over 100 million miles on public roads and extensive simulations across more than 15 U.S. states, we are leading the way in safety and efficiency.The RO Performance team plays a pivotal role in enhancing Waymo's self-driving technology. We are responsible for developing and maintaining the crucial infrastructure needed to process and analyze vast amounts of data from real-world driving logs and simulations.Our systems create essential metrics and dashboards that are vital for monitoring product performance, pinpointing areas for enhancement, and facilitating data-driven decision-making. The insights generated by our team directly impact Waymo's operational strategies, weekly performance evaluations, and, ultimately, the safety and reliability of our autonomous vehicles.In this hybrid role, you will report directly to a Staff Software Engineer.

Join HelloFresh in Warsaw as part of our HelloTech organization, a vital segment of our global technology team comprising over 1000 professionals. We are dedicated to developing digital products that enhance the end-to-end food experience, encompassing meal kits, ready-to-eat meals, and even specialty items like pet food and premium meat & seafood. Our technology platforms empower millions of customers with personalized food solutions every month.Our direct-to-consumer subscription model is fueled by cutting-edge technology that optimizes every customer interaction—from engaging applications and personalization algorithms to pricing strategies and supply chain management. Although our brands operate independently to cater to diverse customer needs, they are unified by shared platforms, data, and operational excellence crafted by HelloTech.At HelloTech, we work in autonomous, cross-functional teams that take ownership of specific products and domains. By collaborating with our Warsaw office, you will contribute to scalable, data-driven products used across various markets, leveraging a modern tech stack and working with international teams to continuously enhance how our customers discover, order, and enjoy HelloFresh products now and in the future.

Location: Warsaw, Poland — Hybrid (4 days on-site / 1 day remote)Contract: B2B · 25–42 k PLN net / month + RSUsJoin Fresha: Pioneering the Beauty & Wellness RevolutionBecome part of Fresha, the world's foremost marketplace platform that's redefining the beauty and wellness sector. With a community of over 120,000 businesses and 450,000 stylists relying on our innovative platform, we have successfully facilitated more than 1 billion appointments globally. Fresha empowers businesses through a comprehensive suite of tools for bookings, point-of-sale, marketing, and beyond, while seamlessly connecting consumers with local services.At Fresha, we harness the power of AI as a true catalyst for feature innovation, going beyond mere coding assistance. Our engineers are equipped with premium tools (Claude, GitHub Copilot, Cursor) that eliminate technical burdens, allowing you to devote your efforts to delivering impactful product features. We seek engineers who can strategically use these tools to foster momentum within our six-week development cycles, effectively accelerating the transition from idea to implementation while ensuring a robust technical foundation to verify, secure, and enhance the final user experience.Your Role as a Senior Backend EngineerAre you eager to make a profound impact in a dynamic and autonomous setting? We're on the lookout for a talented Senior Backend Engineer to join our cross-functional product team based in Warsaw.Key Responsibilities:* Technical Expertise - This role demands a strong technical foundation; hands-on coding skills are essential. It is not a managerial position.* Leadership - Lead the delivery of technical initiatives that span across teams and departments.* Architectural Oversight - Be responsible for the architectural decisions within your tribe.* Technical Guidance - Provide sought-after technical guidance; proactively identify potential technical challenges at the product level and make informed architectural and design choices to mitigate them.* System Enhancements - Drive significant improvements in stability, performance, and scalability across critical enterprise systems.* Project Delivery - Ensure the timely completion of your team’s projects, which will have a direct impact on Fresha’s success.

Join Moss, where we empower finance professionals to automate their workflows and make strategic decisions.Our unique culture is centered around impact and growth, fostering an environment where each team member is encouraged to learn and succeed. Recognized by Sifted’s Rising 100 and LinkedIn's Top Startups, we aim to advance your career while making Moss a lasting success.Our Engineering teams are looking for talented Senior Backend Engineers (f/m/d) to join various teams in Warsaw. Open positions include:Sales EnablementPricing & BillingAcquisitionSpend ManagementActivation & Card SpendIn this role, you will collaborate closely with designers, product managers, and frontend engineers to bring innovative ideas to fruition, ensuring our product provides intuitive and efficient tools for business automation and simplification.

Join Nordsec as a Senior Backend Engineer and be a part of our innovative team in Warsaw. We are seeking a talented engineer experienced in Golang to help us build robust backend systems that power our applications. You will work closely with cross-functional teams to design, implement, and optimize backend services that deliver exceptional user experiences.

Join Saily, where we simplify staying connected while traveling — no roaming fees, no plastic SIM cards, just high-speed, secure mobile data accessible in over 200 destinations. With millions of satisfied customers and countless travelers using Saily at any time, we are dedicated to enhancing their experience.At Saily, we cultivate an AI-driven Product Engineering culture that empowers our engineers to:Own the product development lifecycle from concept to deployment.Leverage AI Agents to automate repetitive coding tasks, maximizing their productivity.Continuously identify and implement improvements within our processes.Embrace curiosity and encourage knowledge sharing.Focus on delivering a seamless, connected experience for our customers.We prioritize growth, contribution, and impactful work over comfort and hierarchy. At Saily, we provide our talented team members with the autonomy and resources they need to excel.Key ResponsibilitiesEnhance our product by developing and maintaining innovative features.Create functionalities that support multi-dimensional personalization, A/B testing, and data analytics.Maintain a robust and high-quality codebase.Continuously seek opportunities to improve code quality and system performance.Provide mentorship on development best practices and offer technical guidance to peers.Contribute to the overall vision and long-term goals of the team.Conduct research and development as needed.Collaborate within a cross-functional team to ensure clear communication among all members.Work alongside engineering, product, and design experts from other teams.Note: This position requires in-office attendance three times a week.

Waymo is at the forefront of autonomous driving technology, striving to become the world’s most trusted driver. Originating from the Google Self-Driving Car Project in 2009, our focus has been on developing the Waymo Driver—The World’s Most Experienced Driver™—to enhance mobility access and prevent traffic-related fatalities. The Waymo Driver is the driving force behind Waymo’s fully autonomous ride-hailing service, having completed over ten million rider-only trips while autonomously covering more than 100 million miles on public roads and tens of billions in simulated environments across 15+ U.S. states.The Waymo Mapping team is dedicated to creating a high-resolution map of the world to facilitate safe autonomous driving. Our innovative mapping process combines automated and manual techniques, along with robust infrastructure for data storage, processing, and distribution. We collaborate closely with various teams within Waymo that utilize map data.Your Responsibilities:Develop and enhance essential labeling tools and systems that drive mapping initiatives at Waymo.Partner with Mapping Operations, UX, and engineering teams to deliver outstanding internal tools.Collaborate with machine learning teams to integrate advanced models into our workflow, significantly increasing scalability.Construct backend infrastructure for the effective storage and processing of diverse map data.Utilize Google's ecosystem to build, deploy, and scale backend services that manage extensive mapping data.Expand systems to map urban environments, supporting Waymo’s rapid growth into new and complex cities.Your Qualifications:Bachelor’s degree or equivalent practical experience.A minimum of 3 years of relevant industry experience.Proficiency in C++ and large-scale data processing.A proactive approach to owning problems end-to-end, tackling various facets of complex systems.A strong passion for software engineering excellence.Preferred Qualifications:Hands-on experience with geospatial data.

Location: Warsaw, Poland — Hybrid (4 days on-site / 1 day remote)Contract: B2B · 25–40 k PLN net / month + RSUsFresha: Innovating the Beauty & Wellness SectorBecome a part of Fresha, the premier marketplace platform revolutionizing the beauty and wellness industry on a global scale. With a network of over 120,000 businesses and 450,000 stylists who trust our platform, we've facilitated more than 1 billion appointments worldwide. Fresha provides an integrated platform for bookings, point-of-sale, marketing, and more, connecting consumers with local services.Your Role as a Backend EngineerAt Fresha, we harness the power of AI not merely as a coding assistant, but as a catalyst for feature delivery. We equip every engineer with cutting-edge tools (Claude, GitHub Copilot, Cursor) to eliminate technical burdens—allowing you to dedicate your efforts to delivering high-impact product features. We seek engineers who can adeptly utilize these tools to propel our 6-week development cycles, accelerating the transition from concept to code, while ensuring the technical integrity and security of the final user experience.Are you poised to make a tangible impact in a dynamic, self-directed environment? We invite you to join our exceptional cross-functional product team in Warsaw as a Backend Engineer.Key Responsibilities:* Collaborate intimately with Product, Design, Frontend, Infrastructure, and Mobile engineers to transition features from discovery to deployment and beyond.* Take ownership of features from concept to observability: encompassing technical design, implementation, testing, and deployment.* Design, develop, and sustain efficient, scalable, and robust Ruby/Elixir code.* Work within a polyglot technology stack (Ruby, Elixir, GraphQL, TypeScript, gRPC) and modern messaging systems (Kafka).* Operate within a Kubernetes-driven framework as we progress towards a microservices architecture.* Apply Domain-Driven Design principles to build high-quality, impactful products from inception to delivery.

Join our dynamic team as a Junior Data Engineer, where you will play a critical role in enhancing modern, real-time data processing capabilities. You will assist in transitioning existing data and ML workflows from batch processing to scalable streaming solutions. This position involves hands-on engineering, close collaboration with Data Scientists, and operational oversight for production data pipelines.Technology EnvironmentUtilization of advanced real-time data streaming technologies for ML model inference.Experience with distributed data processing frameworks that enable scalable, low-latency pipelines.Work with containerized workloads orchestrated in cloud-native environments.Employ monitoring and observability tools to ensure the reliability and performance of data pipelines.Engage with a Python-based ecosystem that supports ML model integration and lifecycle management.Key ResponsibilitiesTransform batch inference workflows into efficient streaming pipelines.Establish streaming semantics to replace batch windows, including micro-batching, windowing, and state management.Design Kafka topic structures, partitioning strategies, and consumer group patterns tailored for prediction workloads.Implement strategies for checkpointing, backpressure handling, and delivery guarantees.Package and version ML model artifacts for streaming jobs to facilitate safe rollouts and rollbacks.Optimize performance for throughput and latency through effective batching strategies and resource allocation.Deploy and manage streaming jobs with comprehensive monitoring and alerting.Integrate streaming outputs into downstream ETL/BI systems seamlessly.Collaborate with Data Scientists on CI/CD for streaming models while monitoring model performance and drift.Team & CollaborationEngage in a distributed delivery model closely coordinated with the central AI/BI team in Germany.Experience daily collaboration through MS Teams, Jira, and Confluence.Utilize Agile methodologies (Scrum/Kanban) within cross-functional squads.

Teltonika Networks is seeking a Mid Backend Engineer in Warsaw, Masovian Voivodeship, Poland. The team develops backend software for networking solutions that power Industry 4.0, Smart City initiatives, and Green Energy projects. Teltonika designs and manufactures connectivity equipment for industrial and enterprise use, including routers, switches, gateways, and modems. Product details are available at https://www.teltonika-networks.com/products. Role overview This position centers on backend development for embedded Linux software used in IoT devices. The Mid Backend Engineer will contribute to API frameworks and help bring new technologies into established systems. Collaboration with R&D teams is a regular part of the role, especially when solving technical challenges. Main responsibilities Design and implement embedded Linux software for IoT hardware Develop and maintain proprietary API frameworks for R&D use Analyze and integrate new technologies into current systems Work with colleagues to resolve complex technical issues Requirements At least 2 years of experience programming in C Minimum 2 years working with APIs Proficiency in Shell and Python scripting for automation Solid understanding of Git version control Experience with Linux-based operating systems Strong written and spoken English Preferred qualifications Technical degree in a relevant field Background working with IoT devices Understanding of computer networking principles Knowledge of cybersecurity practices Experience with Lua programming Familiarity with OpenWrt Benefits Opportunities for career growth within a growing company Challenging projects in industrial networking Private medical care (Medicover Premium) and Multisport card Flexible hybrid work, coordinated in advance with your manager Extra day off for your birthday Team-building events and activities

Fraud Alert:Please be aware that there are fraudulent job postings that may appear legitimate on other platforms. To ensure your application is considered, apply exclusively through our official Sensor Tower website or through posts linked to the Sensor Tower company profiles on platforms like LinkedIn, Indeed, BuiltIn, or Hackajob. At no time will Sensor Tower request any payment, credit card, or bank account information to complete your job application. All communication from Sensor Tower will be via email addresses ending in sensortower.com. Interviews will be conducted via phone or Zoom, and we will not switch to alternative email or text messaging. If you encounter any issues, please reach out to us directly. Include your resume when applying.To Recruitment Agencies:Sensor Tower does not accept unsolicited third-party resumes. Please refrain from sending resumes to our job alias, Sensor Tower employees, or any other locations. We will not be responsible for any fees associated with unsolicited resumes, and we will not pay any third-party agency or company without a signed agreement.About the Role:Are you passionate about developing products that handle large-scale real-world data?At Sensor Tower, we process vast amounts of data to provide insights utilized by thousands of customers. We are in search of inquisitive, driven early-career engineers eager to enhance their skills while assisting us in creating swift, reliable systems that simplify data accessibility and comprehension.You will collaborate closely with seasoned engineers, contribute meaningfully from your first day, and gain insights into the design, construction, and optimization of large-scale systems in a production environment.If you thrive on learning, tackling challenges, and delivering software that users depend on, we would love to connect with you. We have a strong history of rapidly advancing talented juniors, and this role presents a unique opportunity to work closely with senior leadership.Our Engineering Culture:We uphold the belief that "Simplicity is a prerequisite for reliability." We seek engineers who resonate with our core values:- Simplicity: We prioritize straightforward solutions over complex ones and avoid unnecessary complications.- Quality: We produce code that is enjoyable to read, understanding that code is often read more frequently than it is written. We strive for high standards and avoid cutting corners.

Join our team as a Backend Engineer and contribute to our innovative solutions at NordProtect. We are looking for talented individuals with a passion for technology and a strong background in backend development, specifically using Go. In this role, you will collaborate with cross-functional teams to design, implement, and maintain robust and scalable backend systems.

Please note that this opportunity requires relocation to our Milan office.About SatispayAt Satispay, we are on a mission to revolutionize everyday payments, making them simple, equitable, and accessible to everyone. Our vision is to shape the future of money, and we are just getting started. Join our movement that empowers millions, driven by a shared purpose to tackle significant challenges. We thrive on speed, bold thinking, and mutual trust, encouraging each other to challenge the status quo while learning and growing together.If you seek more than just another job and wish to create something impactful alongside a talented team, you’ve come to the right place.Your ResponsibilitiesAs a Senior Backend Software Engineer in the Business Team, you will play a pivotal role in shaping the future of digital welfare payments, managing everything from employer benefits to complex products. You will oversee the end-to-end experience for both employers and employees, ensuring long-term satisfaction. Your responsibilities will include:Drive Multi-Service Solutions: Conduct technical analysis for medium-to-large projects impacting multiple employer domain services. Design highly-available, scalable, secure, and maintainable solutions at the core of welfare offerings.Ensure Technical Quality: Implement robust testing strategies, balancing automation and manual coverage, while monitoring gradual rollouts to ensure precise and reliable welfare distributions.Resolve and Anticipate Blockers: Proactively identify and resolve technical obstacles, fostering knowledge sharing across your organization. Address unique challenges in B2B registration flows and high-volume benefit allocations while ensuring code quality through active reviews.Execution and Ownership: Take full ownership of your projects from inception to completion, delivering features that genuinely meet user needs—from employer signup to the first employee spending their welfare benefits—through seamless and efficient backend integration.

Join Moss, where we empower finance professionals to automate their daily tasks and make strategic decisions.Our unique culture is driven by impact and growth, with every team member dedicated to learning and excelling. Recognized by Sifted’s Rising 100 and LinkedIn's Top Startups, we are committed to propelling your career and achieving lasting success together.We are looking for talented **Mid-Level Backend Engineers (f/m/d)** to join various teams in our Warsaw office, including:Sales EnablementPricing & BillingAcquisitionSpend ManagementActivation & Card SpendIn this role, you will collaborate closely with designers, product managers, and frontend engineers to bring innovative ideas to life. Your goal will be to ensure that our product simplifies and automates everyday tasks through intuitive and efficient tools.