Senior Backend Engineer at altersolutions | Warsaw

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.

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 Fresha, a leading platform in the beauty and wellness industry, as a Senior IT Operations Engineer. In this pivotal role, you will oversee and enhance our IT operational processes, ensuring optimal performance and reliability for our B2B services. Collaborating with cross-functional teams, you will implement innovative solutions that drive efficiency and improve service delivery.

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.

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 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.

At Veeam Software, we pride ourselves on being the experts in Data and AI Trust, dedicated to empowering organizations to fully understand, secure, and ensure the resilience of their data and AI systems. Recognized as the market leader in data resilience and security posture management, we are perfectly positioned to navigate the convergence of identity, data, security, and AI risk. With our headquarters in Seattle and a presence in over 30 countries, we protect the operations of more than 550,000 customers globally, who rely on us to keep their businesses running smoothly. Embark on this exciting journey with us as we continue to innovate, learn, and create significant impacts for some of the world’s largest brands.About the RoleJoin us as we lead the charge in Kubernetes Backup and Disaster Recovery. Our Veeam Kasten platform is specifically designed for Kubernetes data management, providing enterprise operations teams with a seamless, scalable, and secure solution for backup, restore, disaster recovery, and application mobility. With our commitment to continuous optimization and enhancement, we are integrating our tools with SaaS services and expanding support for virtual machines hosted in Kubernetes, ensuring that we meet the evolving needs of our customers.

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 our dynamic team at Evolution as a Backend Developer specializing in Scala. In this role, you will be responsible for designing, implementing, and maintaining high-performance backend systems that are scalable and robust. You will collaborate with cross-functional teams to deliver innovative solutions that meet our clients' needs.

About WPP MediaWPP is the creative transformation company, harnessing creativity to shape a brighter future for our people, planet, clients, and communities. For further details, visit wpp.com.WPP Media operates as WPP’s global media collective, where we unify the best platforms, talent, and partnerships to unlock boundless growth opportunities in an ever-evolving media landscape. Visit wppmedia.com for more information.At WPP Media, we value the strength of our culture and our people, which empowers us to provide exceptional experiences for our clients and each other. In this role, you will play a vital part in upholding WPP and WPP Media’s core values:Be Extraordinary by Leading Collectively to Inspire Transformational Creativity.Create an Open environment by Balancing People and Client Experiences while Cultivating Trust.Lead Optimistically by Championing Growth and Development to Mobilize the Enterprise.Role Summary and ImpactAs a key member of the Global Operations Centre (GOC), you will collaborate with diverse teams across the United States, Europe, and Asia to deliver impactful solutions in a vibrant, multicultural setting. We are on the lookout for a skilled Backend Engineer to join our Data & Technology Solutions team. In this role, you will be essential in designing, developing, and maintaining scalable backend systems that drive our innovative marketing technologies, including the WPP Open AI platform. If you are passionate about crafting high-performance APIs, engaging with large datasets, and shaping the future of AdTech, we would love to connect with you.

Join Larian Studios as a Backend Developer, where you'll play a pivotal role in creating immersive gaming experiences. We are looking for innovative thinkers passionate about backend technologies to help design and implement scalable systems that enhance our gaming platforms.

Bolt for Business is hiring a B2B Sales Specialist in Warsaw to support sales growth among small and mid-sized companies. This position focuses on building relationships with SME and SMB clients and guiding them through the sales process. What you will do Identify and approach potential business clients in Poland Present Bolt for Business solutions clearly and persuasively Negotiate terms and manage the deal process from initial contact to closing What we are looking for Experience working with SME or SMB clients Ability to communicate value and tailor pitches to business needs Motivation to contribute to sales targets and company growth Enthusiasm for working in a growing team This role suits someone who understands the challenges and opportunities of business clients and enjoys working toward ambitious sales goals.

SKELAR is a pioneering Ukrainian venture builder dedicated to establishing international tech businesses. We collaborate with co-founders to assemble top-notch teams that excel in global markets.Currently, SKELAR operates a range of businesses across various niches, from EdTech to marketplaces. These companies consistently rank among the top startups and product firms in Ukraine, achieving high rankings in the App Store and creating platforms that millions use daily. Major media outlets like TechCrunch and Wired have featured SKELAR's businesses.We take pride in a robust team of over 1,000 specialists who possess remarkable expertise and ambitious goals. Our people are the most valuable asset of the company, and we strive to build businesses with the best talents available in the market.RiseGuide is an expert-driven microlearning mobile application designed around the principles and examples of exceptional role models. Our users are guided by insights from Andrew Huberman and Simon Sinek to break harmful habits, enhance their social media presence with strategies from Alex Hormozi and MrBeast, and develop charisma inspired by Robert Downey Jr. and Steve Jobs.Key Facts about RiseGuide:Achieved unit economics in just 6 weeks and have been actively scaling since (we had an incredible Q5 and grew fivefold last year).Over 200,000 paid users, with ratings of 4.6/5 on the App Store and 4.4/5 on TrustPilot.A team of over 60 individuals from successful tech businesses and top management programs worldwide.We aim to redefine the self-improvement industry, granting users access to expert knowledge on demand. To achieve this, we are seeking a Software Engineer (Golang) to help develop our product's backend and turn our ambitious goals into tangible achievements.What We Offer:Opportunity to make architectural decisions and build systems from the ground up.Minimal bureaucracy and maximum speed to market. A small team focused on results and rapid deployment.Fast feedback loops — your solutions will immediately impact production and influence hundreds of thousands of users.The chance to join the team early and define your area of responsibility.Pure Tech: modern stack with Zero Legacy.

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 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 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

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.

Location: Poland About Us: RTB House stands at the forefront of marketing technology, delivering cutting-edge solutions to leading brands and agencies around the globe. Our proprietary ad-buying engine is the world's first to utilize Deep Learning algorithms exclusively, empowering advertisers to achieve remarkable results at every stage of their marketing funnel. We are on the lookout for a Backend Python Developer to become an integral part of our internal team at RTB House. In this role, you will engage in the development of applications and tools that directly enhance our real-time bidding operations. Collaborating with seasoned engineers and product teams, this position offers a fantastic opportunity for developers eager to expand their skill set, tackle real-world challenges, and create robust software that makes a tangible impact.

Join TechBiz Global, where we connect top talent with leading companies. We are currently in search of a Senior JavaScript Engineer to become a vital part of our client’s dynamic team in Warsaw. If you aspire to thrive in a cutting-edge environment and embrace growth, this opportunity is tailored for you.Role OverviewKey Responsibilities:Tackle essential problem domains crucial to our client’s objectives, with the flexibility to transition between teams as our fast-paced environment evolves.Leverage cloud solutions, especially AWS, to engineer, deploy, and enhance scalable services.Engage in the entire project lifecycle—from ideation and design to deployment and maintenance—ensuring timely and top-quality outcomes.Work collaboratively with diverse teams to synchronize integrations and enhance overall system architecture.Promote a robust engineering culture prioritizing code quality, best practices, innovation, and continuous improvement.Proactively identify, troubleshoot, and address potential challenges in distributed financial systems.Participate in small, autonomous teams with rapid release cycles, fostering a strong sense of ownership.Ideal Candidate:Demonstrates expertise in JavaScript, with substantial experience in backend development using Node.js (e.g., Express, NestJS, or similar frameworks).Possesses experience with PostgreSQL and has expertise in designing, architecting, and building reliable, scalable backend systems.Is proficient in working with cloud technologies, particularly AWS