Staff Software Engineer — AI-Driven Modernization & Scale

One Identity, LLC; United Kingdom; Remote; GBP 90,000 - 130,000; Full time

Job summary

One Identity's OneLogin team seeks a Senior Software Engineer to own modernizing legacy systems into scalable services while ensuring reliability. You will work across backend, APIs, cloud, and operations, contributing to production systems and on-call readiness.

This hands-on role emphasizes AI-assisted development, proactive problem solving, and responsible ownership—from design to operation—across the stack.

Qualifications

• Hands-on experience modernizing monolithic systems in production
• Experience with migration patterns (strangler fig, parallel run, phased rollouts)
• Understanding of service boundaries and data ownership during evolution
• Experience maintaining backward compatibility and API/data contracts
• Experience with legacy systems and refactoring under real-world constraints
• Ability to balance migration velocity with system stability and risk
• Familiarity with observability tools to validate migrations
• Interest in AI-assisted development tools and evaluating AI-generated solutions

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

Skills

Backend development

REST APIs

Distributed systems

Production environments

On-call readiness

AI-Augmented engineering interest

Tools

AWS

Datadog

CI/CD

Job description

One Identity's OneLogin team seeks a Senior Software Engineer to own modernizing legacy systems into scalable services while ensuring reliability. You will work across backend, APIs, cloud, and operations, contributing to production systems and on-call readiness.

This hands-on role emphasizes AI-assisted development, proactive problem solving, and responsible ownership—from design to operation—across the stack.