Backend Engineer — Mid-Senior — Transition to Go — Saily

Details

Saily is building a connectivity product that provides secure mobile data in more than 200 destinations. The company has millions of paying customers and hundreds of thousands of travelers browsing through Saily at any given moment.

Saily fosters an AI-native Product Engineering culture in which engineers solve customer problems end-to-end, from idea to production, while AI agents help automate repeatable tasks and maximize engineering impact. The culture emphasizes curiosity, continuous learning, knowledge sharing, autonomy, and customer-focused product development.

Responsibilities

• Enhance the Saily product by developing and maintaining new features.
• Create features supporting multidimensional personalization, A/B experimentation, and analytics.
• Develop and maintain a high-quality codebase.
• Continuously improve code quality and performance.
• Mentor colleagues on development best practices and provide technical guidance.
• Influence the overall vision and long-range goals of the team.
• Perform research and development operations when required.
• Work as part of a cross-functional team and help ensure smooth communication among team members.
• Collaborate with engineering, product, and design professionals from other teams.
• Attend the office three times per week.

Requirements

• More than 4 years of backend development experience.
• Experience with at least one of Python, PHP, or Ruby.
• Experience with system design and knowledge of appropriate design patterns.
• Experience with SQL databases such as MySQL or PostgreSQL.
• Experience with NoSQL solutions such as Cassandra or Redis.
• Previous experience with Kafka.
• Experience with Kubernetes and microservice architecture is a plus.
• Passion for building APIs that are easy to use and understand.
• A collaborative mindset and willingness to discuss, rethink, and redesign ideas to create shared success.

Technologies and Tools

• Backend: Go, MySQL, Kafka, Docker, Kubernetes, AWS, Redis
• Frontend: Next.js, React.js, TypeScript, GraphQL, Tailwind CSS, Cloudflare Workers
• iOS: SwiftUI, Xcode, Combine, Swift Package Manager, MVVM architecture
• Android: Kotlin, Android Studio, Hilt, Coroutines, Jetpack Compose, MVVM architecture
• AI tools: Claude Code, OpenAI Codex, OpenCode, Cursor with Composer

Benefits

• Online and in-person training programs, access to Coursera and Skillshare, mentorship, and internal career opportunities.
• Additional vacation days based on tenure, plus days off for sick leave, special occasions, and parenting.
• Premium private health insurance in Lithuania and Poland.
• Subscriptions to Calm, Headspace, and Mindletic, along with resilience and mindfulness training and mental health events.
• In-house gyms, Multisport and Urban Sport cards, online workouts, group mobility sessions, fitness guidance, and individual consultations.
• Company workations abroad.
• The option to work from different locations.
• Gifts for birthdays, work anniversaries, weddings, and new family members.
• Summer camps for children and flexible working arrangements for parents.
• Team-building activities, company events, and summer and winter celebrations.
• Access to the Vilnius Cyber City headquarters, including silent rooms, gyms, a game room, music room, and coffee bar.