Backend Engineer | Mid-Senior | Go | 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. Saily has millions of paying customers and hundreds of thousands travelers browsing through Saily at any given moment.

To build the best product for our customers we foster AI-native Product Engineering culture, where:

• The Engineer is the builder, who is responsible for solving customer problems end-to-end (idea to production)
• AI Agents are the enablers who write most of the code and solve repeatable tasks to help the Engineers maximize their impact
• Everyone contributes to making Saily effective by suggesting new areas for improvement to delegate to agents and then implementing the changes
• Curiosity, learning and sharing are everyone's responsibility
• Customer, having a comfortable, connected, hassle-free journey is never lost from the focus
  

We value growth over comfort, contribution over hierarchy, and impact over process. At Saily, we believe in giving sharp people context, autonomy, and AI as their multiplier to allow them to just do their best work.

Main Responsibilities

• Build a completely new sophisticated microservices system for the new eSim Product
• Create features to support layers of multi-dimensional personalization, A/B experimentation, and analytics
• Develop and maintain a high-quality codebase
• Seek to improve code and performance constantly
• Mentor colleagues on development best practices & provide technical guidance
• Exercise influence on the overall vision and long-range goals of your team
• Perform R&D operations whenever required
• Use AI agents for specifications, coding, analysis, testing, and iteration
• Work as part of a cross-functional team and help to ensure smooth communication between all team members
• Collaborate with engineering, product, and design professionals from other teams
  

Core Requirements

• Experience working with Go (4+ years)
• System design is nothing new to you, and you know what patterns to use, when, and why
• Previous experience in working with K8s and microservice architecture is a plus
• Previous experience with SQL (MySQL, PostgreSQL) and NoSQL (Cassandra, Redis) solutions
• Previous experience with Kafka
• Passionate about building APIs that are easy to use and simple to understand
• Strong product mindset: focus on problems, outcomes, and impact—not just tickets or tasks
• You are curious about AI and excited to work with agents
  

Tools You Will Use

• Go
• MySQL
• Kafka
• Kubernetes
• AWS
• Redis
• AI tool like Copilot Cursor
  

Salary Range

• Gross salary: 19,800 — 33,400 PLN/month