Backend Engineer (Go) - Payments Experience

Join Our Innovative Team as a Senior Backend Software Engineer! The Mobile Fulfilment Systems team at Ocado Group is pioneering state-of-the-art automation solutions for in-store and warehouse online order fulfilment. We harness the power of distributed backend systems, user-friendly mobile applications, and advanced autonomous robots to facilitate rapid, scalable, and cost-efficient order collection. As a key member of our Mobile Fulfilment Systems team, particularly within the In-Store Fulfilment (ISF) division, you'll be involved in designing and developing distributed cloud-based systems, PWA mobile applications, and web technologies aimed at automating the fulfilment of online customer orders at scale. What is In-Store Fulfilment? ISF is a comprehensive cloud-based solution that empowers stores to efficiently fulfil customer orders, enhancing the shopping experience while minimizing operational costs. We are currently operational in over 1,000 stores across 11 countries and 4 continents, handling more than 300,000 customer orders weekly. In Your Role as a Senior Software Engineer, You Will: Design, develop, and maintain large-scale, high-availability distributed systems. Lead technical initiatives from conception through to implementation, fully owning the planning, coordination, design, and execution processes. Ensure solutions consistently meet quality standards by adhering to best practices in testing, code quality, monitoring, and alerting. Contribute to the long-term architectural and product vision. Utilize AI tools, such as Claude Code, Gemini, and GitHub Copilot, to enhance our development processes. Engage in all phases of the software development lifecycle within an agile team framework. Continuously seek to enhance our processes, workflows, and tools. Collaborate closely with business and product partners to translate system requirements into engineering solutions. Participate in our on-call rotation to support production services. Mentor and train both new and existing team members in their professional development.

About the Role Ocado Group’s Mobile Fulfilment Systems team in Sofia, Bulgaria builds automation technology for online order fulfilment in retail and warehouse settings. The group combines distributed backend systems, mobile apps, and autonomous mobile robots to support rapid, scalable, and cost-effective order processing. This position sits within the In-Store Fulfilment (ISF) division. The team focuses on designing and developing cloud-based systems, progressive web apps, and web technologies that automate online order fulfilment at scale. About In-Store Fulfilment (ISF) ISF is a cloud-based platform that helps retailers efficiently fulfil online orders, improve the customer experience, and reduce operational costs. The system is live in over 1,000 stores across 11 countries and 4 continents. Each week, it manages more than 300,000 customer orders, covering every stage from routing and cubing to picking, buffering, loading, and dispatching. What You Will Do Architect, develop, and maintain large-scale distributed systems with high availability. Lead technical projects from initial planning through design and delivery. Apply best practices in testing, code quality, monitoring, and alerting to ensure reliable solutions. Shape the long-term architectural and product direction for the team. Integrate AI tools such as Claude Code, Gemini, and others into backend systems. AI and Engineering Focus AI is already part of the software development process at Ocado. The team is growing its AI capabilities and welcomes backend engineers with hands-on experience or a strong interest in AI. This role offers the chance to advance AI initiatives while contributing to core engineering projects.

Join the Global Bank tribe at SumUp, where we are developing the essential infrastructure and core services that empower our merchants with digital bank accounts. Our vision is to be the foremost banking partner for small merchants worldwide, delivering a seamless, straightforward, and affordable banking experience tailored to their unique needs.As a member of the Global Bank tribe, you will play a pivotal role in building SumUp's digital banking ecosystem. Collaborate within a diverse, autonomous, and cross-functional team that brings product ideas from concept to reality. Embrace the opportunity to work with talented colleagues from 32 different nationalities spread across cities like Cologne, Berlin, São Paulo, Sofia, London, and Vilnius, all driven by a shared commitment to ownership, purpose, and supporting small businesses in thriving.As a Senior Backend Engineer, you will take charge of enhancing and maintaining a high-throughput banking ecosystem for our merchants within the Global Bank Tribe. Your contributions will be instrumental in architecting and evolving our global banking platform, ensuring high availability, scalability, and observability across various regions. If you're eager to gain hands-on experience in building products for business accounts, card payments, and transfers across Europe and Latin America for SumUp's Global Bank, we invite you to embark on this exciting journey with us!

Join Our Mission to Empower Wealth BuildingAt trading212, we are revolutionizing the trading and investing landscape by crafting innovative products that resonate with our users.We champion a culture of excellence and agility, driving our success in a rapidly evolving market.Currently, we proudly serve over 4.5 million clients, managing more than €30 billion in assets—a true testament to the trust we have established in just a few years.Your RoleDesign and implement solutions with a comprehensive understanding of business challenges, our service architecture, and the relevant technologies and infrastructure.Be involved in every phase of the software development lifecycle (SDLC)—from gathering requirements and designing implementation to coding, testing, deploying, and monitoring. You will take full ownership of your code and ensure its continuous improvement.Develop robust solutions focused on performance, scalability, and resilience—your code will operate in a high-stakes environment where downtime, latency, and data loss are unacceptable.Collaborate within small, autonomous teams that operate on short release cycles. We value agile methodologies and a balanced approach to processes that avoid chaos without compromising speed.Engage in knowledge sharing and continuous learning with colleagues. As our company evolves, so must we, and constructive feedback is one of our strongest tools for growth. QualificationsProven experience in developing services within a microservice architecture, having contributed to a highly scalable and performant system comprising over 200 microservices.Strong understanding of common communication protocols. You should be adept at utilizing HTTP/WebSockets and AMQP, with the ability to choose the appropriate protocol based on the context.Familiarity with at least one widely-used web framework, regardless of programming language. Our language-agnostic system empowers engineers to select the most suitable language for specific tasks. We strive for a harmonious balance between cutting-edge technologies and proven solutions.A comprehensive understanding of system performance, scalability, and security best practices.

At SumUp, we recognize that small businesses are the driving force behind Europe's economy. Our mission has always centered around empowering these businesses to flourish. We are now embarking on an exciting new venture: a stablecoin designed to ensure payments are instant, cost-effective, and fully compliant with regulations.This is a unique opportunity to contribute to a product that sits at the convergence of fintech, cryptocurrency, and regulatory compliance, supported by a profitable organization that serves over 4 million merchants across 35+ markets.What’s the opportunity?We are seeking a Senior Backend Engineer who is passionate about building innovative solutions from the ground up. This role is ideal for someone who thrives in fast-paced environments and desires to enhance their technical skills in a high-impact field. You will collaborate closely with our Staff Engineer and cross-functional teams to bring our stablecoin project to fruition.This newly created position is pivotal for a high-priority project. It entails a dynamic, complex environment filled with learning opportunities, perfect for an individual who enjoys tackling challenging problems and delivering high-quality code.Your responsibilities will include:Building from the ground up: Participate in technical discovery and MVP development for SURO, coding daily in Kotlin or Go.Designing reliable systems: Assist in creating high-SLA, service-oriented systems that integrate with our ledger, reconciliation, and treasury platforms.Delivering quality: Write clean, maintainable code with a focus on reliability, security, and observability.Collaborating across teams: Work alongside Product, Finance, Legal, and Banking teams to ensure features comply with regulatory standards.Expanding your skills: Learn from seasoned engineers and deepen your expertise in payments, compliance, and blockchain technologies.Owning features end-to-end: Take full responsibility for specific components from design through deployment and monitoring.

Join the Global Bank tribe where we are revolutionizing the banking infrastructure for merchants. Our mission is to empower small merchants worldwide with a digital business account that simplifies their banking needs, making us the go-to banking partner for them.As a Senior Backend Engineer, you will play a pivotal role in transitioning from fragmented regional systems to a unified global infrastructure, enabling millions of merchants to access seamless banking services tailored to their needs.Your expertise will be crucial in designing and developing a fully distributed, event-driven system that is resilient and compliant across multiple regions.In this role, you will primarily work with Kotlin while having the opportunity to engage with Elixir and Golang. We embrace Extreme Programming methodologies, focusing on small iterations, daily deliveries, and prioritizing technical design quality and deep problem-solving.Our technology stack includes Kotlin, Golang, Elixir, Java, AWS, Kafka, PostgreSQL, and Kubernetes, leveraged by observability tools such as Prometheus, Grafana, and Honeycomb. Additionally, we utilize AI-assisted development tools including Cursor and GitHub Copilot.

At SumUp, we celebrate the everyday heroes who possess the courage to pursue their passions and the determination to turn their dreams into reality. Our mission revolves around empowering small business owners with innovative, user-friendly financial solutions that simplify the management of their enterprises. With a founder's mentality and a 'team-first' attitude, our diverse teams across Europe, South America, and the United States collaborate to ensure that these entrepreneurs can thrive in their endeavors. The Global Bank team at SumUp is responsible for developing the foundational infrastructure and services that provide merchants with digital bank accounts, enabling them to manage their finances efficiently and reliably. Within this team, the Balance Management Squad is pivotal. We are currently nearing a significant milestone: the consolidation and modernization of our balance management system in Europe. Our next ambitious project is to establish a global transaction history service—a unified platform that offers merchants consistent and transparent insights into their financial activities across all regions. As a Backend Engineer, you will play a crucial role in modernizing existing systems while balancing innovation and stability. You will collaborate with teams across various regions to build reliable services that can navigate diverse markets with unique regulatory requirements. If you are passionate about solving complex problems in high-load systems, have a curiosity for banking, and are eager to join a team that embraces challenges, we would love to connect with you.

Join Us in Empowering Wealth CreationAt trading212, we are redefining the landscape of trading and investing by crafting innovative products that resonate with users. Our commitment to excellence and rapid execution has been pivotal to our growth.Currently, we proudly support over 4.5 million clients, managing more than €30 billion in assets—an impressive reflection of the trust and scale we’ve achieved in just a few years.Your Role and ResponsibilitiesTake a comprehensive approach to problem-solving, integrating business challenges, service architecture, and the technological landscape into your solutions.Lead the full software development lifecycle (SDLC), from requirements gathering and design through coding, testing, deployment, and monitoring. You will own your code, ensuring it remains robust and optimized for enhancements when opportunities arise.Design for performance, scalability, and resilience, ensuring your code operates flawlessly in a demanding environment where downtime, latency, and data loss are unacceptable.Collaborate within small, autonomous teams with rapid release cycles, leveraging agile methodologies to maintain high velocity while preserving necessary processes.Engage in continuous learning and knowledge sharing within the team, as our growth is contingent on the company’s collective evolution and constructive feedback. What We Expect from YouA solid understanding of common communication protocols, with comfort in using HTTP, WebSockets, and AMQP, alongside the ability to discern appropriate application contexts.Experience with at least one widely-used web framework, regardless of programming language. Our technology-agnostic platform allows engineers to choose the most suitable language for specific tasks, balancing cutting-edge solutions with proven technologies.A strong grasp of RDBMS concepts, including indexing, transactions, isolation levels, and locking mechanisms, with the skills necessary to design high-performance databases.

Join our talented team at devexperts as a Backend Engineer, where you'll play a pivotal role in developing cutting-edge software solutions. Your expertise in backend technologies will help us enhance our products and provide exceptional service to our clients.

At SumUp, we champion the everyday heroes—those with the courage and determination to pursue their passions and realize their dreams.We place small business owners at the center of our mission, crafting powerful and user-friendly financial solutions designed to empower them in managing their businesses. With a founder's mentality and a collaborative, 'team-first' spirit, our diverse teams across Europe, South America, and the United States unite to ensure that small business owners can thrive in their endeavors.About the TeamThe Payments Reporting team is integral to SumUp’s financial infrastructure, developing systems that millions of merchants depend on daily to reconcile, report, and make sense of their finances. We are currently on an exciting journey to build a reporting platform that accommodates both external integrators and internal teams at scale, delivering functionalities from file-based exports to real-time API reporting. This role has emerged due to our ambitious growth outpacing the capacity of our current team of three backend engineers, and we need someone who can take significant ownership of complex backend tasks, allowing the team to accelerate critical architectural improvements.What You Will DoDevelop and maintain backend reporting features, including Payout Reports, Payment Reports, Fee Invoices, and Transaction Reports.Design and manage Reporting APIs (like Transaction History and Payout History) that cater to both external integrators and internal stakeholders.Lead the migration of core payments functionality from legacy systems, modernizing the infrastructure that supports our reporting platform.Ensure the operational health of reporting services through effective monitoring, incident response, and performance optimization.Actively engage in planning and refinement sessions, providing technical assessments and effort estimations.Mentor junior engineers through code reviews, collaborative sessions, and knowledge sharing.

ABOUT TIDEAt Tide, we empower small and medium-sized enterprises (SMEs) to optimize their operations, saving both time and money. We provide not only business accounts and banking services but also a comprehensive suite of user-friendly administrative solutions ranging from invoicing to accounting.Tide is revolutionizing the small business banking sector with over 1.8 million members worldwide, including regions such as the UK, India, Germany, and France.By leveraging cutting-edge technology, we design all solutions with SMEs in mind. With rapid onboarding processes, minimal fees, and innovative features, we thrive on making data-driven decisions to fulfill our mission: to enable SMEs to focus on what they love.Tide Facts:Available for SMEs in the UK, India, Germany, and FranceOver 1.8 million members: 800,000 in the UK and 1,000,000 in India, with rapid growthSecured over $300 million in fundingMore than 2,500 diverse employees globallyHeadquartered in Central London, with a technology and member support center in Sofia, Bulgaria, and additional offices in Serbia, Romania, Lithuania, Hyderabad, Gurugram, New Delhi, Berlin, Paris, and Luxembourg.ABOUT THE TEAM:Our engineering team, comprising 40+ dedicated professionals, is focused on designing, developing, and managing a rich product catalog across various business domains (e.g., Payment Services, Business Services). With an extensive roadmap ahead, we constantly face exciting challenges. We trust our engineers to make impactful technical decisions that influence multiple teams and shape the future of Tide's Global One Platform. This is a unique chance to significantly contribute by taking ownership of engineering practices within a rapidly growing company!Our engineers work in small, autonomous teams dedicated to specific domains, overseeing the entire lifecycle of various microservices within Tide’s service catalog. They self-organize, collaborate to tackle technical challenges, and establish their own guidelines within the different Communities of Practice, regardless of their current position in our Growth Framework.ABOUT THE ROLE:Engage with our event-driven microservice architecture, which currently includes over 200 services managed by 40+ teams. You will be responsible for defining and maintaining the services your team owns (you design, build, run, and scale them globally).

Welcome to Kaizen Gaming!At Kaizen Gaming, the driving force behind Betano, we stand as one of the leading GameTech companies globally, operating across 19 dynamic markets. Our commitment is to harness the latest technological advancements, delivering unparalleled experiences to millions of customers who rely on us for their entertainment.With a vibrant team of over 2,700 Kaizeners from more than 40 nationalities across three continents, we embrace diversity and innovation.Proudly recognized among the Best Workplaces in Europe and certified as a Great Place to Work, we promise that every day here is unique and filled with potential. Are you ready to Press Play on your career?About the Role:As a Lead Principal Backend Engineer, you will be pivotal in designing and evolving high-performance, scalable backend systems. We seek a technical expert who excels in leadership and mentorship, guiding engineers at all levels. Your expertise will drive the development of our robust software solutions while collaborating with cross-functional teams to achieve excellence.Your Responsibilities Include:Architecting & Innovating: Partner with our agile team to create scalable, secure, and high-performing backend systems that power our innovative solutions.Code Craftsmanship: Write clean and efficient code that serves as the backbone of our technology stack.Mentorship: Inspire and mentor fellow tech leaders, fostering skill development and the adoption of best practices.Performance Optimization: Spearhead initiatives to identify and enhance system performance, ensuring seamless user experiences.Integration Collaboration: Work closely with cross-functional teams to guarantee smooth system integration.Tech Trendsetter: Stay ahead of technological trends, applying emerging technologies to augment our capabilities and disrupt the industry.Best Practices Advocate: Collaborate with Principal Engineers to establish company-wide best practices and foundational software development processes.Strategic Vision: Define and concentrate on the technical roadmap, aligning it with the company's long-term goals beyond immediate business needs.

Ocadogroup is hiring a Senior Software Engineer in Sofia, Bulgaria. This position focuses on designing, developing, and implementing software solutions that support the company’s business goals. Role overview The Senior Software Engineer will work closely with colleagues from different teams to build and deliver products that align with customer needs. The role involves hands-on development and active participation in the full software lifecycle, from concept to deployment. What you will do Create and refine software designs to address business challenges Develop, test, and implement new features and applications Collaborate with cross-functional teams to ensure product quality Requirements Experience designing and building software solutions Ability to work collaboratively with colleagues from various disciplines Strong interest in technology and delivering results that make a difference

About the Role Entain is looking for a Senior Software Engineer with deep experience in Angular to help build and improve software that shapes our user experience. This position is based in Sofia. What You Will Do Develop and maintain Angular applications that support our products and services Work closely with engineers and designers to solve technical challenges Contribute to decisions that improve code quality and user experience Help deliver reliable, high-quality software in a collaborative environment Who We’re Looking For Strong background in Angular and front-end development Experience working on complex software projects Comfortable collaborating with cross-functional teams Motivated to make a real impact on products and users

SumUp’s Payments Tribe develops tools that make transactions easier for small businesses. The team in Sofia, Bulgaria, is searching for a Junior Backend Engineer with experience in Golang to help build and maintain these payment solutions. What you will do Collaborate with engineers to develop and maintain backend services using Golang Contribute to new features that support payment processing for users worldwide Assist in improving the reliability and usability of payment systems Role impact This position supports SumUp’s mission to simplify payments for small businesses and enhance the experience for users globally.

Role Overview Lifted An Upwork Company is hiring a Senior Web Software Engineer in Sofia. This position focuses on building and maintaining web applications that meet high standards for quality and user experience. The role involves hands-on design, implementation, and ongoing support of web projects. What You Will Do Design and develop web applications from concept through deployment Implement features that improve usability and performance Maintain and update existing web solutions as requirements evolve Collaborate closely with team members to deliver reliable results What We Look For Strong experience with web development technologies Commitment to writing clean, maintainable code Ability to work well with others and share knowledge Focus on delivering a smooth, effective user experience

About the Team: As a Senior Android Engineer in the Mobile Platform Squad, you will play a crucial role in the foundation of Mobile Engineering at SumUp. Your team is tasked with developing and maintaining an environment that empowers Mobile Developers to efficiently deliver high-quality products. Additionally, you will provide assistance and support to SumUp employees interacting with our mobile applications. We foster an engineering culture rooted in autonomy, collaboration, and innovation. You will liaise with mobile engineers across the organization as your initiatives will have a widespread impact. The squad is focused on: Maintaining CI/CD pipelines for mobile projects. Creating tools and infrastructure to enhance the developer experience. Supporting and optimizing the codebase across SumUp's mobile applications. Driving long-term technical improvements at scale across the organization. What You Will Do: Shape the core experience for merchants and developers using SumUp’s Android ecosystem. Develop and maintain tools, frameworks, and infrastructure that enhance the consistency, scalability, and reliability of our mobile applications. Collaborate with cross-functional teams, including product management, design, and backend development, to deliver seamless user experiences. Work on CI/CD systems, developer tools, and performance enhancements to streamline mobile development processes. Mentor team members and provide technical guidance across various projects. Uphold high engineering standards and continuously elevate them by introducing new technologies and best practices. Take ownership of technical projects from conception to implementation, ensuring alignment with business objectives and technical standards.

LucidLink develops cloud-based solutions that allow teams to access data securely from anywhere. The platform is built for handling large files and extensive data sets, offering a user experience similar to a local hard drive. Founded by storage industry veterans in 2016, LucidLink enables real-time collaboration for creative organizations, including major names in media and entertainment. The company operates from San Francisco and maintains an engineering office in Sofia, Bulgaria, serving customers in over 40 countries. Role overview The Senior Fullstack Software Engineer position is based in LucidLink’s Sofia office. This role centers on building and improving the platform that supports instant, secure data access and real-time collaboration. The work directly affects how teams worldwide manage and share large-scale content. What you will do Work on technical challenges that shape global collaboration, especially in media and entertainment. Contribute to a platform designed for performance, security, and ease of use with massive data sets. Collaborate with a team of over 230 professionals, where individual input quickly influences product direction. What we value Integrity, innovation, and empathy in daily work and team interactions. Commitment to personal growth and learning as the company expands. Supportive culture that encourages advancement and open communication. Benefits Flexible paid time off Competitive salary Stock options Health coverage

Our mission is to empower individuals to create wealth.At Trading 212, we are transforming the landscape of trading and investing by developing outstanding products that our users adore.Our dynamic team is composed of highly motivated individuals who pursue excellence and cherish autonomy.With over 4.5 million clients and more than €30 billion in assets under management, our growth and trust in the market speak volumes about our success.We are in search of passionate and experienced Principal Software Engineers to drive innovation and scalability in our systems.