Backend Engineer | Senior | Go | Product & Startup Experience | Saily

Backend Engineer | Senior | Go | Product & Startup Experience | 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

Requirements

• 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

• Bonus Points

• 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

• Tools You Will Use

• Backend: Go, MySQL, Kafka, Docker, Kubernetes, AWS, Redis

• Frontend: Next.js, React, TypeScript, GraphQL, Tailwind CSS, Cloudflare Workers

• iOS: SwiftUI, Xcode, Combine, SPM, MVVM

• Android: Kotlin, Hilt, Coroutines, Jetpack Compose, MVVM

• AI tools: Claude Code, OpenAI Codex, OpenCode, Cursor

What We Offer

• Sharpen your edge: training, mentorship, and room to grow — always
• Take the time you need: extra vacation days, sick days, and time off when life calls
• Get premium healthcare: private health insurance in Lithuania and Poland — fully covered
• Protect your peace: enjoy free subscriptions to Calm, Headspace, and Mindletic, and our own resilience and mindfulness trainings
• Own your fitness: in-house gyms, sport cards, online workouts, and personal guidance — on us
• Pack your bags for workation: experience our company-wide trip abroad to the fullest
• Work from anywhere: work from wherever keeps you in the zone
• Celebrate your milestones: birthdays, weddings, and new family members — all deserve a gift
• Parent with ease: children’s summer camps and flexibility around the schedule — because parenting never pauses
• Join the party: team building and company events people talk about for months
• Unlock Cyber City: coffee bar, open gyms, kids’ room, music room, massage chairs — our Vilnius HQ is yours to enjoy