Backend Engineer Senior Saily

At Saily, we're removing the hassle of staying connected while traveling no roaming fees, no plastic SIM cards, just lightning-fast, secure mobile data in 200+ destinations. Millions of paying customers trust us, and hundreds of thousands of travelers browse Saily at any given moment. We're not looking for someone to close tickets. We're looking for a builder someone who has shipped products real people use, felt the pain of a 2 AM incident on something _they_ care about, and gets a kick out of seeing a metric move because of something they built.

Our Culture: AI-native Product Engineering

The Engineer is the builder responsible for solving customer problems end-to-end, from idea to production

AI Agents are the enablers they write most of the code and handle repeatable tasks, so you maximize your impact

Everyone makes Saily more effective you suggest what to delegate to agents, then implement the changes

Curiosity, learning, and sharing are everyone's job

The customer a traveler on a comfortable, connected, hassle-free journey never leaves our focus

We value growth over comfort, contribution over hierarchy, and impact over process. We give sharp people context, autonomy, and AI as their multiplier and expect their best work in return.

Main Responsibilities

• Own product features end-to-end: from shaping the idea with Product and Design to shipping, measuring, and iterating
• Build features supporting multi-dimensional personalization, A/B experimentation, and analytics
• Make technical decisions with a product lens you'll know the "why" behind every "what"
• Develop and maintain a high-quality, high-performance codebase in Go
• Mentor colleagues and raise the bar on engineering best practices
• Influence your team's vision and long-range goals your opinion on _what_ we build matters as much as _how_
• Run R&D spikes when the path forward isn't obvious
• Collaborate across engineering, product, and design in a cross-functional team

• 5+ years of backend development experience, with strong skills in Python, PHP, Ruby, or similar and readiness to work in Go daily
• Product company experience, ideally startup or scale-up you've worked where speed, ambiguity, and ownership are the norm, not the exception
• B2C experience strongly preferred you understand what it means to build for millions of users you'll never meet, where small UX details and performance directly hit revenue and retention
• Solid system design skills: you know which patterns to use, when, and why
• Experience with SQL (MySQL, PostgreSQL) and NoSQL (Redis, Cassandra) solutions
• Experience with Kafka or similar event-driven systems
• Passion for building APIs that are easy to use and simple to understand
• A collaborative mindset you love discussing, rethinking, and redesigning ideas toward shared success

Nice to have

• You've built your own product a side project, a startup (successful or not), an indie app, anything you took from zero to real users. We find that people who've carried a product themselves think differently: they obsess over the user, they ship, they own outcomes. If that's you, tell us about it it matters more to us than logos on your CV
• Experience with K8s and microservice architecture
• A track record of experiments shipped, hypotheses tested, and impact measured (not just features delivered)
• Comfort working AI-native: Claude Code, Codex, Cursor you see AI as a multiplier, not a threat

• Growth is built into how we work. Extensive online and in-person training programs, access to platforms like Coursera and Skillshare, a mentorship program, and internal career moves when youre ready for something new your development has no ceiling here.
• Rest isnt a reward its part of the deal. Enjoy extra vacation days that grow with your time here, plus additional days off for sick leave, special occasions, and parenting.
• We provide premium private health insurance so you have peace of mind and fast access to care whenever you need it. Available in Lithuania and Poland.
• We provide free subscriptions to top-rated Calm and Headspace apps, offer resilience and mindfulness trainings, and run dedicated mental health events.
• We offer in-house gyms, Multisport and Urban Sport cards, and online workouts. Need something tailored? Our Physical Well-Being experts are here with group mobility sessions, fitness guidance, and one-on-one consultations.
• The entire company flies out abroad. The days are packed with workshops, activities, concerts, and real time together.
• When you need a reset, switch location and work from wherever keeps you sharp, creative, and in the zone.
• The moments that make life special shouldnt pass quietly. Birthdays, work anniversaries, weddings, new family members each is marked with a special gift.
• We organize summer camps for the little ones and offer flexibility that lets you show up both for your family and your team.
• Get ready for team buildings that bring people closer, year-round company events that are equal parts educational and energizing, and the highlights everyone waits for our iconic summer and winter celebrations.
• Whether Vilnius-based or visiting from remote, our Vilnius HQ is fully yours to enjoy. Need focus? Silent room. Need energy? Open gyms. Need a break? Game room, music room, coffee bar. Its a modern workspace built with your comfort in mind.