Mid-Senior Backend Engineer | Go | Saily

Join Saily, where we are revolutionizing mobile connectivity for travelers. Say goodbye to roaming fees and plastic SIM cards, and enjoy ultra-fast, secure mobile data across over 200 destinations. With millions of paying customers and hundreds of thousands of travelers engaging with Saily at any moment, we are dedicated to enhancing the travel experience.At…

Join our innovative team at Nordsec as a Mid-Senior Backend Engineer specializing in Go. In this role, you will be responsible for designing and implementing robust backend solutions that drive our platform's performance and scalability. Collaborate with cross-functional teams to enhance our technology stack and deliver high-quality software solutions. Your expertise will contribute to our mission of providing secure and efficient digital services.

Saily is changing how travelers access mobile data, removing the need for roaming fees and physical SIM cards. The platform delivers fast, secure connectivity in more than 200 destinations, serving millions of customers and supporting hundreds of thousands of travelers worldwide. The Senior iOS Engineer role at Saily in Krakow centers on building solutions that directly address customer needs, from initial concept through to production. The team works within an AI-native Product Engineering environment, where engineers have access to AI agents that automate routine tasks. This approach frees up time for deeper, more meaningful work and encourages everyone to suggest and implement improvements. How the team works Engineers handle the full cycle of product development, solving real customer problems. AI tools automate repetitive work, letting engineers focus on high-impact tasks. Continuous improvement is expected and supported, team members regularly propose and drive changes. Curiosity and sharing knowledge are valued parts of the culture. The main goal is to create a smooth, reliable experience for travelers using Saily. Culture and values Saily puts growth, contribution, and impact first. The company values autonomy and provides context and AI-powered tools so engineers can do their best work, rather than focusing on hierarchy or rigid processes.

About Saily Saily helps travelers stay connected in over 200 destinations, offering mobile data without roaming fees or the hassle of physical SIM cards. Millions of people rely on our service to make travel smoother and more convenient. Our Engineering Culture Saily builds on an AI-native Product Engineering approach. Here, engineers own their work from idea to deployment, always focused on solving real customer problems. AI agents handle repetitive tasks, so engineers can spend more time on meaningful solutions. Engineers take responsibility for projects from start to finish. AI tools support daily work by automating routine steps. Team members suggest and implement improvements to the Saily platform. Curiosity, ongoing learning, and sharing knowledge are core values. Our main goal: make travel easy and stress-free for customers. How We Work Saily values personal growth, active contribution, and real impact. Hierarchy and rigid processes take a back seat to autonomy, context, and the right tools. Team members are trusted to do their best work with the support they need.

Join Saily, where we are revolutionizing connectivity for travelers by eliminating roaming fees and plastic SIM cards, providing secure and speedy mobile data across 200+ destinations. With millions of satisfied customers and countless travelers engaging with our platform, your contributions will directly impact their journeys.We cultivate an AI-native Product Engineering culture that empowers engineers:Ownership of projects from inception to deploymentAbility to deliver features with flexible specificationsCollaboration with product, design, data, and engineering teamsWork within small, autonomous teamsLeverage AI agents for coding, testing, and analysisAchieve double the productivity of a typical Senior EngineerEnhance our internal agent network and development processesAdapt across the technology stack as requiredPrioritize user and business outcomes above mere outputCore RequirementsDemonstrable experience in designing and deploying AI-driven tools, resulting in successful organizational adoptionHands-on experience in developing full-stack features for mobile or web applications (frontend and backend)Strong problem-solving skills and a passion for innovation

Saily, a division of Nord Security, seeks a Senior Automation QA Engineer based in Krakow. This role centers on raising application quality through automated testing methods. Collaboration is key. The Senior Automation QA Engineer will work with colleagues from various teams to uphold high quality standards and help ensure a dependable experience for users. Role overview Develop and maintain automation tests to improve software quality Work with cross-functional teams to identify and address quality issues Support a consistent and reliable user experience through rigorous testing Location This position is based in Krakow.

SKELAR is a Ukrainian venture builder dedicated to creating international tech businesses. Together with our co-founders, we assemble strong teams to conquer global markets.Currently, SKELAR has a portfolio of several businesses across various niches, ranging from EdTech to marketplaces. Our companies rank among the top startups and product companies in Ukraine, achieving high visibility in the App Store and developing platforms that millions of users rely on. Additionally, our businesses have been featured in renowned media outlets such as TechCrunch and Wired.We take pride in our robust team of over 1000 professionals who possess exceptional expertise and ambitious goals. Our people are the most valuable asset of the company, and we strive to build businesses alongside the best talents in the market.We are currently on the lookout for a Mid-Level DevOps/System Administrator to join our business unit, Relatio.Relatio is a technology company focused on creating products that enhance romantic relationships. Our application assists users globally in building harmonious and healthy partnerships through self-development. As part of our Growth initiatives, we are actively expanding our R&D efforts in adjacent topics.Having launched in the summer of 2023, we have already achieved significant success — establishing our unit economics and actively scaling towards becoming a larger enterprise. Each new employee now has the opportunity to become a leader in their domain; it all depends on your initiative and ambition.Challenges Awaiting You:Maintain and develop the company’s hybrid infrastructure: Google Cloud, Proxmox VE, Linux servers, and internal services;Ensure the stable operation of servers and systems: monitoring, alerting, backup, recovery, and participate in incident resolution;Enhance CI/CD processes and automate routine technical tasks;Support Atlassian products: Jira, Bitbucket, Confluence;Assist employees with technical issues: VPN, access, accounts, internal services;Organize and automate access management processes using roles, groups, policies, and relevant tools;Document infrastructure, services, and key technical processes.What Matters to Us:

Saily, part of Nordsec, builds technology that helps travelers stay connected without roaming fees or physical SIM cards. The platform delivers secure, high-speed mobile data in over 200 destinations, serving millions of paying customers and hundreds of thousands of active travelers at any moment. This Senior Android Engineer role centers on Kotlin development for Saily’s mobile platform. The team values engineers who shape solutions from idea to launch, always with the traveler’s experience in mind. How Saily Works Engineers design and build solutions to real customer problems, not just code to a spec. AI agents automate repetitive work, freeing engineers to focus on high-impact tasks. Every team member suggests and implements improvements to the product and process. Continuous learning and sharing knowledge are core expectations. Customer experience drives every decision. Culture and Approach Saily emphasizes growth, contribution, and real impact over hierarchy or rigid process. Team members receive context, autonomy, and AI-powered tools to do their best work.

Join the ARQ TeamARQ is rapidly emerging as one of the world's leading fintech companies. Our mission is to revolutionize the way individuals manage their finances across borders by creating infrastructure that facilitates seamless value transfer. As we embark on this exciting journey, every new team member has the opportunity to shape the future of our product, culture, and growth. If you're driven by ambitious challenges, a desire for global impact, and the excitement of working within a top-tier team, ARQ is the ideal place for you.Position OverviewAs a Backend Engineer at ARQ, you will be instrumental in designing, developing, and maintaining robust, secure, and efficient backend systems that power our cutting-edge financial products. Your collaboration with a talented team will lead to innovative solutions that enhance financial inclusion and transform the way users manage their money.Key ResponsibilitiesEngage in greenfield development and enhance existing systems.Contribute to projects including the development of REST APIs, engineering microservices, and improving systems essential for our business operations (e.g., card payments, treasury management, transaction booking, crypto liquidity).Utilize Java 25 for backend development along with a Postgres database.Leverage Spring Boot for rapid and high-quality delivery.Adopt a pragmatic approach to developing business logic, focusing on clean, maintainable code with an emphasis on speed and effectiveness through TDD, DDD, and continuous integration & delivery.QualificationsProven experience in backend development with strong proficiency in Java.Bachelor's Degree or higher in Computer Science, Mathematics, Physics, or related Engineering/Science fields.A quick learner with a driven and results-oriented mindset, possessing excellent communication skills in English (both verbal and written).A history of building complex products utilized by millions in high-growth startup environments.

About TripadvisorAt Tripadvisor, we believe in connecting travelers with experiences that are truly worth sharing. As a leading global platform, we are committed to becoming the most trusted source for travel guidance, enabling people to find the best accommodations, restaurants, and activities through our comprehensive range of brands including Tripadvisor, Viator, and TheFork.Our Experiences Engineering team, distributed across Europe, is pivotal in managing our platform and mobile applications, along with their supporting infrastructure. We create the systems that empower operators to enhance their businesses and facilitate third-party access to our diverse inventory. Our tools are designed to support our customer service teams in delivering exceptional service to travelers and operators around the globe.We are currently seeking a Software Engineer I to join our dynamic and expanding team. This position is available to candidates situated within a reasonable commuting distance (generally within 1.5 hours) of our Kraków office. We embrace a flexible work model that prioritizes remote work while also valuing essential in-person collaboration moments, including periodic gatherings at your nearest office for team engagement and planning.At Tripadvisor Experiences, we foster a friendly and enjoyable work environment focused on achieving results. Our engineers collaborate closely with product managers and designers throughout the entire software development lifecycle—from conceptual design to coding, testing, deployment, and beyond. Most of our engineers push code to production every few days, participating in a daily release cycle.Our engineers thrive on versatility, tackling a variety of technical challenges. This role has a backend focus, with opportunities to engage in frontend projects occasionally. While a willingness to learn is crucial, prior expertise in frontend development is not required; we provide training on that aspect during your onboarding process.The technologies we utilize include Java, React, TypeScript, GraphQL, Kubernetes, SQL, and NoSQL databases, all running on AWS infrastructure.

Join the ARQ Team!At ARQ, we are revolutionizing the fintech landscape. Our aim is to transform global financial interactions, creating a seamless infrastructure for value transfer across borders. As we embark on this exciting journey, every new team member plays a crucial role in shaping our innovative products, company culture, and future growth. If you are passionate about tackling significant challenges and making a global impact while being part of a talented team, ARQ is the perfect place for you!Your RoleAs a Backend Engineer, you will be responsible for designing, developing, and maintaining robust backend systems that support our cutting-edge financial products. You'll work closely with a skilled team to craft solutions that promote financial inclusion and help users manage their finances more effectively.Key ResponsibilitiesFocus on developing new systems as well as enhancing existing ones.Engage in projects including building REST APIs, creating microservices, and evolving essential systems like card payments, treasury management, and cryptocurrency liquidity.Utilize Java 25 for backend development alongside a PostgreSQL database.Leverage Spring Boot to ensure quick and efficient delivery of solutions.Adopt a pragmatic approach to developing business logic, focusing on writing clean, maintainable code, and employing methodologies like TDD, DDD, and continuous integration and delivery.QualificationsA minimum of 5 years of experience in backend development with a strong command of Java.A Bachelor's degree or higher in Computer Science, Mathematics, Physics, or related engineering/science fields.A quick learner with a driven, results-oriented mindset and exceptional communication skills (fluent in English, both verbal and written).Proven experience in developing complex products utilized by millions in high-growth startup environments.

Join Our Team as a Backend EngineerAt dolarapp, we are seeking a skilled Backend Engineer to design, develop, and maintain robust backend systems that support our cutting-edge financial solutions. You'll work with a dynamic team dedicated to driving financial inclusion and revolutionizing how people manage their finances.Your Role & ResponsibilitiesEngage in greenfield development and the enhancement of existing systems.Develop REST APIs, engineer microservices, and improve critical business systems such as card payments, treasury management, transaction booking, and crypto liquidity.Utilize a technology stack centered around Java 25 with a Postgres database.Leverage Spring Boot for rapid and efficient delivery.Adopt a pragmatic approach to developing business logic with a focus on clean, maintainable code, using methodologies like TDD, DDD, and CI/CD.QualificationsA minimum of 5 years of experience in backend development, particularly with Java.Bachelor's Degree or higher in Computer Science, Mathematics, Physics, or related Engineering/Science fields.A quick learner with a driven attitude and excellent communication skills in English, both verbal and written.Proven experience in creating complex products used by millions in fast-paced startups.Why Work With Us?Attractive salary package.Sign-on stock options to share in the company’s success.Discretionary performance-related bonuses in the form of stock options.Paid annual leave.Ownership of the development process with a focus on customer impact.Access to the latest technologies.Collaborative team environment to foster skill development.

Fraud Alert: Please be aware that scammers frequently post fake job listings. To ensure your application is valid, only apply for roles directly through the Sensor Tower official website or through reputable job platforms like LinkedIn, Indeed, BuiltIn, or Hackajob. Sensor Tower will never request payment or financial information during the application process. Communication from Sensor Tower will only come from email addresses ending in sensortower.com. All interviews will be conducted via phone or Zoom, and we will not shift communication to any external email or text message. If you encounter any issues, please let us know. Remember to attach your resume when applying.To Recruitment Agencies: Sensor Tower does not accept unsolicited resumes. Please refrain from sending resumes to our job alias, employees, or other locations. Sensor Tower is not liable for any fees related to unsolicited applications, and we will not pay any third-party agencies without a signed agreement.About the Role: We are seeking skilled engineers who can effectively scale our database operations, handling vast amounts of data (in the range of tens of terabytes) while providing meaningful insights. As a Back End Engineer at Sensor Tower, you will contribute to building exceptional products and features for our users. In our dynamic and flat organizational structure, you will have a significant influence on product development.A Day in the Life:Interviewee: Engineering Team Lead - Sasha YelkovenkaWhat does your day-to-day look like as a Software Engineer?I handle a considerable volume of data that is constantly growing. My primary responsibility is to ensure our customers can access this data swiftly and utilize convenient tools for consumption. I appreciate the culture of ownership and accountability in my work.How do you collaborate as a remote employee?Sensor Tower fosters an excellent remote working atmosphere. We frequently collaborate via Zoom to leverage our collective expertise for superior results.

Join our dynamic team at Tanium as a Senior Helpdesk Engineer and play a pivotal role in enhancing our customer support experience. You will be responsible for providing top-tier technical assistance and ensuring that our clients receive the highest quality of service. This is an exciting opportunity for you to leverage your expertise in IT support and help shape our service offerings.

NFQ serves as a pivotal technology partner for HomeToGo, where a passionate team of software engineers and data science experts spearheads the innovation that fuels a marketplace showcasing the world’s largest selection of vacation rentals. As we expand HomeToGo’s tech team in Lithuania, we are on the lookout for top-tier talent to join our dynamic organization.HomeToGo, the premier marketplace for vacation rentals, boasts millions of listings from trusted partners like Booking.com, Vrbo, and TripAdvisor. Whether you’re searching for vacation homes, cabins, beach houses, apartments, condos, houseboats, castles, or farm stays, HomeToGo seamlessly integrates pricing, destination, dates, and amenities to help travelers find their ideal accommodation for any journey around the globe.Established in 2014, HomeToGo operates localized applications and websites in 25 countries across Europe, North America, South America, Australia, and Asia-Pacific. The company's portfolio also includes recognizable brands such as Agriturismo.it, AMIVAC, Casamundo, CaseVacanza.it, e-domizil, EscapadaRural, Tripping.com, and Wimdu.We are seeking a Senior Software Engineer (PHP) to join our Distribution Team, responsible for developing systems that connect HomeToGo with a multitude of partners—from individual agents to major industry players like Google, TUI, and Amadeus. In this role, you'll design and maintain diverse channels that fuel our growth, integrating our B2B tools and public channels into a cohesive, high-performance ecosystem that distributes millions of vacation rentals worldwide. You will collaborate with a team of PHP and React (TypeScript) Software Engineers focused on delivering self-service software projects with a strong emphasis on data quality. Our engineers engage throughout the entire software lifecycle and work with a wide array of technologies. Moreover, you will be part of a supportive team of intelligent, dedicated, and driven individuals who make the workplace enjoyable.

Join ARQ as a Senior Platform EngineerARQ stands at the forefront of the fintech revolution, transforming how individuals manage their finances on a global scale. We are dedicated to creating seamless and innovative solutions that empower users to interact with money without borders. As one of the fastest-growing companies in our sector, we offer a thrilling opportunity for talented individuals to significantly impact our culture, product, and expansion.If you are passionate about tackling substantial challenges and aspire to be part of a world-class team, ARQ is the ideal place for you!Your RoleWe seek an exceptional, hands-on Senior Platform Engineer who approaches infrastructure development with a software engineering mindset. Our engineering ethos emphasizes fully type-safe, declarative, and testable infrastructure as code. We invite engineers who share our values to apply.The perfect candidate will exhibit a fervent passion for programming, possess extensive knowledge, and demonstrate the ability to delve into any technical area necessary to empower our product engineering team to deliver unparalleled financial management solutions.You will design and implement high-quality automated systems to manage a multitude of backend services and databases across various Kubernetes clusters, processing thousands of data jobs and CI/CD builds weekly. If this excites you, we want to hear from you!Key ResponsibilitiesDesign and implement a secure, highly available infrastructure that supports a modern, rapidly growing financial services firm.Facilitate the rapid deployment of new infrastructure for our product engineering team through the thoughtful creation of shared Infrastructure as Code libraries, CLI tools, and coding patterns.Identify and resolve infrastructure issues and opportunities in collaboration with the broader engineering team.Strategize and execute infrastructure change rollout techniques, continuously integrating best practices and security enhancements.Oversee multi-region infrastructure and deployments to ensure compliance with security and availability standards.Develop, maintain, and optimize high-volume CI infrastructure and reusable pipeline templates for a microservices architecture.Implement GitOps workflows for declarative application deployments.

nfq is hiring a Senior PHP Software Engineer in Krakow. This position centers on building, maintaining, and improving software solutions using PHP. The work involves hands-on development with a focus on quality and reliability. Role overview This role calls for experience with PHP to support the full software lifecycle. The Senior PHP Software Engineer will contribute to both new development and ongoing enhancements of existing systems. Collaboration Work closely with colleagues from different teams to ensure products align with client needs. Communication and teamwork are important aspects of this position. What you will do Develop and maintain PHP-based software Enhance existing solutions for better performance and stability Collaborate with cross-functional teams on project delivery

Join ActiveCampaign as a Senior Data Software Engineer, where your expertise in high-quality software engineering will shape our data management landscape. In this pivotal role, you will architect advanced data systems and uphold stringent best practices to ensure our platforms are both resilient and scalable. Your responsibilities will encompass designing and developing the software necessary for seamless data movement and management across our organization.

Tripadvisor helps travelers find experiences, advice, and options for any journey. Through brands like Tripadvisor, Viator, and TheFork, the company supports millions in discovering places to stay, activities to try, and restaurants to visit. Its platforms connect a global audience with travel content, recommendations, and marketplaces for experiences, lodging, and dining. Role overview The Senior Engineering Manager will join the Tripadvisor Experiences team, known as Viator. Viator provides access to over 400,000 experiences worldwide, from guided city tours to outdoor excursions. The team focuses on making it easy and reliable for travelers to plan and book memorable activities. Location and contract This is a hybrid role based in Krakow. The position is offered as a permanent employment contract. B2B contracts are not available for this role.

Are you passionate about creating powerful systems that enhance financial independence? Join DolarApp, a visionary startup dedicated to transforming access to dollar-based financial services throughout Latin America. As a Senior Python Engineer, you will architect, develop, and sustain scalable, secure, and high-performing backend systems that fuel our groundbreaking products. Collaborate with a skilled team to devise solutions that promote financial inclusion and revolutionize how individuals manage their finances. If you're eager to tackle intricate challenges and contribute significantly to a rapidly expanding company, we want to hear from you!What You'll Be DoingYou will be instrumental in developing the foundational infrastructure that supports our operations, including customer support bots and fincrime AI agents that will transform fintech operations.You will adopt a pragmatic approach to crafting our business logic, prioritizing clean code and maintainability, with a focus on rapid development through Test-Driven Development (TDD), Domain-Driven Design (DDD), and continuous integration and delivery.