Senior Backend Engineer - Ruby on Rails

Emma Sleep is hiring a Senior Backend Engineer with expertise in Golang to help shape the technology behind its global platform. This position is based in Lisbon and centers on developing and refining backend systems that keep Emma Sleep’s operations running smoothly. Key responsibilities Design, build, and maintain backend services using Golang Improve system performance and scalability Support the reliability and efficiency of Emma Sleep’s technology platform Location This role is located in Lisbon.

Aghanim is looking for a Senior Golang Backend Developer to help build and refine backend services that power billing and payment processing systems. This position is based in Lisbon. What You’ll Do Design and develop backend services focused on billing and payment flows Work with Go (Golang) as the primary backend language Integrate with a range of external payment providers and financial APIs Build and maintain systems that manage transactions, retries, reconciliation, and provider communications Implement and optimize billing logic and payment processing pipelines Emphasize reliability, accuracy, and observability in all financial operations Write maintainable, well-tested production code Monitor and troubleshoot payment and transaction workflows About the Role Develop scalable backend services using Golang Integrate seamlessly with multiple payment providers Ensure financial operations are reliable and accurate Handle transaction processing, including error handling and reconciliation Location This role is based in Lisbon.

Location: Fully Remote - NYC preferred. Open to US remote or EU remote (Must be able to overlap with EST 6+ hours daily)Employment Type: Full-timeCompensation: $200,000 - $275,000Join an exciting opportunity with our client, a pioneering leader in the blockchain industry, as a Senior Golang Engineer on their core backend team. They have developed an innovative real-time parimutuel prediction market platform on Solana, designed to seamlessly integrate rapid 60-second to 30-minute prediction markets into both livestream environments and web platforms.After successfully raising a $1M pre-seed round in April 2026, led by key venture players in the Solana ecosystem, they are expanding their infrastructure to accommodate high-concurrency traffic patterns. As one of the initial backend engineering hires, you will take ownership of essential systems that facilitate market creation, settlement, and automated payouts during high-stakes global livestream events.Key Responsibilities:System Ownership: Architect, develop, and sustain production-grade, low-latency backend systems capable of managing thousands of concurrent market resolutions.Concurrency & Performance: Implement advanced Go concurrency patterns to handle real-time data flows and high-frequency transaction processing.Infrastructure & Scaling: Oversee and optimize distributed systems, ensuring idempotency, consistent ordering guarantees, and robust failure recovery.Observability: Spearhead production debugging initiatives using logs, metrics, tracing, and profiling to ensure 24/7 system reliability.Technical Autonomy: Operate independently in a dynamic startup environment, influencing the foundational architecture of an emerging product category.

Join our dynamic team at Aghanim as a Tech Lead/Senior Golang Developer, where you will spearhead the design and development of robust backend services tailored for billing and payment processing systems.This pivotal role demands extensive expertise in Go backend architecture, paired with hands-on experience in integrating with various payment providers and financial infrastructures.You will engage in crafting systems that manage payment processing, billing logic, provider integrations, and transaction workflows, ensuring the utmost reliability, scalability, and accuracy in all financial operations.

Role overview Riskified seeks a Senior Backend Engineer in Lisbon to help build and maintain the backend systems that power its fraud prevention platform. The position centers on improving efficiency and reliability for clients around the globe. This work supports the technical foundation that enables Riskified’s services to scale and perform. What you will do Design, develop, and maintain backend systems for the core platform Collaborate with cross-functional teams to deliver technical solutions Tackle complex backend challenges to support platform growth and stability Contribute to the adoption and implementation of new technologies Impact Senior Backend Engineers at Riskified influence both product direction and client outcomes. The work directly supports Riskified’s ongoing efforts to lead in fraud prevention and deliver reliable results to customers.

Join the Kaizen Gaming Family!At Kaizen Gaming, the driving force behind Betano, we stand as one of the largest GameTech companies globally, operating across 19 markets. Our commitment to leveraging state-of-the-art technology empowers us to deliver unparalleled experiences to our millions of valued customers.Our vibrant team of over 2,700 diverse 'Kaizeners', hailing from more than 40 nationalities and spanning three continents, is what sets us apart. We take pride in being recognized among the Best Workplaces in Europe and have earned the prestigious Great Place to Work certification across our offices. Are you ready to Press Play on your potential?About the RoleAs a Senior Backend Engineer, you will be an integral part of a self-sufficient Agile team, collaborating closely with the Product Owner, Agile Delivery Lead, Automation Testers, and fellow Software Engineers to create a competitive edge for Kaizen while delivering a unique online experience to our customers. You will also engage with talented backend professionals within our Backend Chapter.Your Responsibilities Include:As a Senior Software Engineer at Kaizen, you will manage a variety of projects, ranging from our customer-facing websites and mobile applications to our internal tools and backend services, all designed to handle high volumes of traffic.Take full ownership of our applications throughout an engaging development journey.Develop innovative solutions from concept to production.Transform requirements into efficient and sophisticated technological systems, leveraging our large-scale, highly available infrastructure.Design, build, and maintain efficient, reusable, and reliable code.Explore new technologies to discover efficient solutions for everyday challenges.Deliver high-value features swiftly.Challenge existing processes and foster improvement within the team and product.

About the Role Renesas Electronics Corporation is hiring a Senior Backend Software Engineer in Lisbon. This role focuses on designing, building, and maintaining backend systems that support Renesas products. What You'll Do Develop and maintain backend software components Work with cross-functional teams to deliver reliable solutions Contribute to the architecture and performance of core systems Location This position is based in Lisbon.

Join the Tripadvisor Group, where we connect people with unforgettable experiences and strive to be the world's most trusted source for travel and adventure. Utilizing our vast portfolio of travel brands and advanced technology, we aim to engage a global audience and facilitate meaningful connections with our partners across diverse travel categories including accommodations, restaurants, and unique experiences. The Tripadvisor Experiences Engineering team, distributed across Europe, plays a pivotal role in managing Tripadvisor.com and our mobile applications, alongside the supporting infrastructure. We empower operators to grow their businesses while enabling third parties to leverage our comprehensive inventory. Our dedicated team provides essential tools that support our customer service representatives in delivering exceptional service to travelers and operators worldwide. We are in search of a Senior Software Engineer to become part of our dynamic team. This position is available to candidates who can commute (generally within a 2-hour radius) to one of our office hubs in Lisbon. We appreciate flexibility in work arrangements and value the importance of in-person interactions for collaboration and connection. Expect a remote-first work model complemented by periodic office gatherings for team planning and engagement. At Tripadvisor, our engineers thrive on tackling a diverse array of technical challenges. This backend-focused full-stack role primarily involves backend development, with opportunities to engage in frontend projects as well. While a willingness to learn is essential, expertise in frontend development is not required at the outset, as we offer on-the-job training. Our collaborative environment is designed for productivity, where engineers work closely with product managers and designers throughout the entire software development lifecycle—from design and coding to testing and deployment. Most engineers deploy code to production every few days within our daily release cycle. The technology stack at Tripadvisor includes Java, React, Typescript, GraphQL, Kubernetes, SQL, and NoSQL databases on AWS. While strong proficiency in Java is mandatory, familiarity with the entire stack is not a prerequisite; a passion for learning is what we value most. Why Work with Us? Competitive compensation packages, including base salary, annual bonuses, and more. “Work your way” approach offering flexibility to cater to your lifestyle and needs.

Join our dynamic team at Renesas Electronics as a Senior Backend Engineer, specializing in Django or FastAPI. In this role, you will be responsible for developing robust backend systems that support our innovative electronics solutions. We are looking for a passionate engineer who thrives in a collaborative environment and is eager to tackle complex technical challenges.

About Air AppsAt Air Apps, we embrace a vision of expansive thinking and agile execution. Founded by a family in 2018, our mission is to revolutionize planning with the world's first AI-powered Personal & Entrepreneurial Resource Planner (PRP). With our roots in Lisbon, Portugal, and additional offices in San Francisco, we have successfully maintained self-funding while achieving over 100 million downloads globally.Our commitment to long-term innovation drives us to continually challenge conventional wisdom, expanding the frontiers of AI-driven solutions that genuinely transform lives. Here, you will play a pivotal role in crafting products that empower individuals worldwide.Join us on our mission to redefine resource management and make a lasting impact.The RoleAs a Backend Software Engineer, you will take charge of designing, developing, and maintaining the server-side components of our applications. You will work collaboratively with product managers, frontend developers, and other cross-functional teams to deliver robust and scalable backend services that enable essential features and foster rapid growth.Please be aware that this posting is intended to expand our talent pool while we prepare to officially launch the job. We will reach out to you as soon as it becomes available.ResponsibilitiesAPI & Service Architecture - Design and implement RESTful or GraphQL APIs, microservices, and business logic utilizing Node.js and TypeScript.Database Design & Integration - Model and manage data queries using Supabase and PostgreSQL, including functions, row-level security, and real-time features.Cloud Infrastructure - Deploy and oversee services on Google Cloud Platform (GCP), particularly with Cloud Run, Cloud Functions, IAM, and Pub/Sub.Code Quality & Testing - Create clean, testable code utilizing unit, integration, and end-to-end testing frameworks (e.g., Jest). Participate in code reviews and uphold quality assurance practices.Security & Reliability - Develop secure-by-default solutions for authentication, authorization, and data protection, adhering to Clean Code and Clean Architecture principles.Monitoring & Operations - Establish logging, monitoring, and operational practices to ensure system reliability.

Join our dynamic team at inetum2 as a Java Backend Engineer. We are looking for a talented individual who is passionate about backend development and eager to contribute to innovative technology solutions. In this role, you will collaborate with cross-functional teams to design and implement high-quality software solutions that meet our clients' needs.

Join Dashlane as a Backend Software Engineer and be part of a dynamic team dedicated to enhancing digital security for our users worldwide. In this role, you will design, develop, and maintain scalable backend systems that support our innovative applications. Your contributions will directly impact the user experience and the overall success of our products.

Internship Overview evolution is looking for a Backend Engineering Intern to join the team in Lisbon. This position offers hands-on experience with real projects and the chance to work closely with seasoned engineers. What to Expect Collaborate with the engineering team on active backend projects Gain practical skills and learn from experienced colleagues Contribute ideas and support ongoing development work This internship is designed for those eager to grow technical abilities in a supportive, team-driven setting.

Join Our Team at Kaizen GamingKaizen Gaming, the driving force behind Betano, stands as one of the largest GameTech companies globally, actively engaging in 19 markets. Our commitment to harnessing advanced technology allows us to deliver exceptional 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 take pride in our diversity and innovation. Recognized as one of the Best Workplaces in Europe, and certified as a Great Place to Work, our environment promises excitement and growth every day. Are you ready to Press Play on your potential?About the RoleDesign, develop, and maintain high-quality, efficient, and reusable code.Create interfaces that connect components of diverse subsystems within a high-transaction production environment.Optimize application performance, quality, and responsiveness.Diagnose and resolve bottlenecks, bugs, and complex challenges.Our Technology StackOur services are primarily developed using C# / ASP.NET, with newer implementations utilizing .NET Core. The front-end is powered by Vue.js for new applications, while legacy systems employ server-rendered (Razor) views combined with jQuery and Knockout.js. We rely on MS SQL Server for data storage, complemented by Redis and ElasticSearch when appropriate. RabbitMQ serves as our message broker, and we utilize GitLab for version control and CI, alongside the Atlassian suite for ticketing and documentation.Your QualificationsA minimum of 1 year of development experience with C# / ASP.NET / MVC (either full framework or .NET Core).Fundamental understanding of web technologies, such as HTTP.Experience in data access, including databases and APIs.Familiarity with unit testing is a plus.Perks of Joining Kaizen Gaming Flexible hybrid working model. Personalized onboarding support through a buddy system. Attractive salary package with performance-based bonuses.‍ Comprehensive health and life insurance for you and your family. Monthly meal allowance.⭐ Continuous development through our 360° feedback framework. Unlimited access to Udemy and ongoing training opportunities.

Join AirApps as a Backend QA Engineer where you will play a crucial role in ensuring the quality and reliability of our backend systems. You will collaborate with developers to design and implement test plans, identify bugs, and enhance our products' performance. This is an exciting opportunity to contribute to a growing tech company in a vibrant city.

About the Role tgs is looking for a Backend Engineer (Python or Go) to join the Unbabel division in Lisbon. This team builds and maintains backend services that support enterprise-grade translation solutions across platforms. The work centers on making language technology smarter and more seamless for clients worldwide. What You Will Do Design and implement core backend services and reliable system architectures. Build, maintain, and improve codebases with an emphasis on testability and efficiency. Develop, optimize, and support key services and infrastructure in live production environments. Enhance system architecture to improve scalability, resilience, and performance. Analyze complex technical problems and help prioritize initiatives alongside product and engineering teams. Encourage continuous improvement, automation, code quality, and strong architectural practices. Work with teams across disciplines to deliver solutions that adapt to changing business and technical needs. Troubleshoot and prototype quickly to address platform and service challenges as they arise. Location Lisbon, Lisboa, Portugal

airapps is looking for a DevOps Engineer with a focus on backend systems to join the team in Lisbon. This position centers on building and maintaining backend infrastructure that supports the company’s applications and services. Role overview The DevOps Engineer - Backend Specialist will take charge of implementing backend solutions that scale and remain reliable. Collaboration with development teams is a key part of the job, especially when refining deployment workflows and improving infrastructure. What you will do Develop and maintain backend systems to support business needs Work alongside developers to streamline deployment processes Contribute to infrastructure enhancements for better reliability and scalability Help ensure smooth, uninterrupted operation of applications and services Location This role is based in Lisbon.

Role overview Riskified seeks a Backend Engineer in Lisbon to help build and maintain the systems behind its fraud prevention products. This position centers on developing backend applications that keep client transactions running smoothly. The work involves ensuring reliability and scalability across key services. What you will do Design, develop, and maintain backend applications that support fraud prevention efforts Work with colleagues from other teams to deliver solutions that perform well under load Help ensure the stability and scalability of systems that process client transactions

About the Role TransPerfect’s Unbabel team in Lisbon is looking for a Backend Engineer with experience in Python or Go. This role focuses on building and improving backend services that power cross-platform translation solutions for enterprise clients. The team values reliability, scalability, and seamless performance as it develops intelligent language products. Main Responsibilities Design and implement reliable backend architectures and core services. Create, maintain, and optimize codebases with attention to testing and efficiency. Develop, support, and enhance critical services in production environments. Advance the architecture to support scalability, resilience, and high performance. Analyze complex technical problems and help prioritize initiatives with product and engineering teams. Promote continuous improvement, automation, code quality, and adherence to architectural best practices. Work with cross-functional teams to deliver solutions that meet changing business and technical needs. Troubleshoot and prototype to address platform and service challenges quickly. Location This position is based in Lisbon, Lisboa, Portugal.