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

Don’t quite match every requirement?
Our technical bar is high, but we’d rather help you reach it than lose a great person over it. If your mindset and technical potential make an impression, but your Go skills aren’t quite there yet, we may invite you to the GO Masterclass: fully funded access to the Three Dots Labs’ Golang training platform. Level up, come back, and interview again — we’d love to see you grow into this role!

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