Senior Software Engineer (Platform)

Nexl is looking for a Senior Software Engineer to join Keystone, our internal platform team. Keystone builds the common capabilities that make every other engineering team at Nexl faster.

Near-term, that means consolidating several authentication mechanisms into one, building a design system with tokens and a shared component library, and replacing a feature flagging setup that no longer scales. This is foundational work that every other team will build on, so we need one of our strongest engineers in this seat. This isn’t a growth hire. We’re looking for someone who raises the bar from day one.

AI tools such as Claude Code and Cursor are core to how we build, and you’re expected to use them to ship faster and at higher quality. Deep fundamentals still matter just as much, including architecture, distributed reliability, security and system thinking. They’re what let you direct AI effectively and catch where it gets things wrong.

This is a high-ownership role for someone who designs before they build, can bring multiple teams along with a change, and wants to shape how a fast-growing LegalTech company builds.

Must haves:

• You’ve led a consolidation across multiple teams, such as an auth or identity migration, a shared platform rollout, or a common service other teams adopted. You can explain how you got teams to move.
• You have concrete depth in distributed reliability (idempotency, duplicate delivery, retries and failure recovery), with examples from systems you’ve run.
• You design before you build, and can show evidence of writing architecture decisions and getting alignment upfront.
• You’re agentic-first in practice. You use Claude Code, Cursor or equivalent tools as your primary workflow, and you’ve improved the shared harness rather than only using it.

Nice to haves:

• Ruby on Rails experience. Our core platform is a Rails monolith, so strong Rails depth is a real advantage, but platform leadership matters more.
• Golang experience.
• React experience.
• Experience building or rolling out a design system or shared component library.
• Experience with feature flagging platforms at scale.
• Experience in multi-tenant, data-heavy SaaS applications.
• Knowledge of DevOps practices, Infrastructure as Code, or cloud infrastructure (AWS or Azure).
• Experience designing or orchestrating multi-agent systems.

What Success Looks Like:

• Teams across engineering are on a single, consolidated authentication approach, and the migration happened with buy-in rather than force.
• Product teams build on the shared design system and component library by default.
• Feature flagging scales with the business and stops being a source of friction.
• Your architecture decisions are documented, aligned before build, and hold up over time.
• The shared services Keystone owns are reliable, and other teams trust them.
• Improvements you make to the shared agentic harness are adopted across engineering and multiply the team’s collective output.