Senior Software Engineer – System Modernization

Overview

One Identity's OneLogin team is seeking Senior Software Engineers who operate with high ownership, strong technical judgment, and a bias for action. These roles are designed for engineers who identify and solve problems proactively — not just execute assigned work. 

Senior Engineers at OneLogin are expected to operate as T-shaped engineers: deep in a primary domain while remaining capable across the stack (backend, APIs, cloud, and operations). You will play a key role in maintaining product velocity, improving system reliability, and reducing operational burden. 

 

This is a hands-on role that includes on-call responsibilities and requires a strong commitment to modern engineering practices, including AI-augmented development. We are looking for engineers who take full ownership — design, build, test, deploy, and operate — rather than handing work off between silos. 

 

In this role, you will execute and evolve an incremental modernization strategy (e.g., strangler fig), safely transitioning legacy systems into scalable services while maintaining reliability and system continuity. 

Responsibilities

Execute and evolve an incremental modernization strategy, safely transitioning legacy systems into well-bounded services while maintaining reliability and continuity 

 

• Decompose monolithic systems incrementally using patterns such as strangler fig • Manage coexistence between legacy and modern systems during transition • Design clear service boundaries, contracts, and data ownership models • Ensure backward compatibility and safe evolution of APIs and data during migration • Improve performance, scalability, and maintainability as part of modernization efforts • Identify and prioritize high-impact areas for migration based on risk and value 

 

Ideal Experience: 

• Hands-on experience incrementally modernizing monolithic systems in production environments • Experience with migration patterns such as strangler fig, parallel run, or phased rollouts • Strong understanding of system decomposition, including service boundaries and data ownership • Experience maintaining backward compatibility and managing API/data contracts during system evolution • Experience working with legacy systems and evolving them under real-world constraints • Experience debugging and validating behavior across both legacy and newly extracted services • Ability to balance migration velocity with system stability and risk • Familiarity with observability practices to validate system behavior during migrations • Experience using AI tools to analyze legacy systems, understand behavior, or accelerate refactoring and migration efforts 

Qualifications

Software Development

• 4+ years of professional software engineering experience with ownership of production systems and operational improvements
• Strong backend development experience (Ruby, Node.js, or similar)
• Solid understanding of REST APIs, service contracts, distributed systems, and common software design patterns
• Experience working across backend systems, APIs, and production environments

Quality & Testing

• Hands-on experience with automated testing across unit, integration, and API layers
• Strong ownership of code quality, including testing, debugging, and validation

AWS & Cloud-Native Experience

• Experience building and operating cloud-native services in AWS
• Familiarity with CI/CD practices and modern deployment workflows

Observability & Production Operations

• Experience using observability tools (e.g. Datadog or equivalent) to monitor, troubleshoot, and resolve production issues
• Familiarity with incident response and continuous reliability improvements

On-Call & Incident Response

• Willingness to participate in a 24/7 on-call rotation and support production issue resolution

AI-Augmented Engineering

• Experience with or strong interest in AI-assisted development tools (e.g. GitHub Copilot, ChatGPT, Cursor) and the ability to effectively evaluate AI-generated solutions

Company Description  

One Identity enables organizations of all sizes to better secure, manage, monitor, protect, and analyze information and infrastructure to help fuel innovation and drive their businesses forward. With team members around the globe, we intend to continue to grow revenues and add value to customers.  

  

When you join our team, you will have the opportunity to build and develop products at a scale few others can provide. Our product portfolio serves a large base of customers and we are addressing the strategic imperatives for enterprise businesses. Working with some of t