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Case study

Hardening a network-security admin platform while it kept shipping

Cato Networks logo

Role: Software Engineer

Context

Cato Networks provides a SASE platform — networking and security delivered as a cloud service. Operations teams around the world administer networks, people, certificates, and security policy through its admin consoles.

The problem

The admin surface mixed new mission-critical screens that had to be built from scratch with legacy infrastructure that had grown fragile. Both mattered: operators depend on these consoles for live security operations, so neither breakage nor a feature freeze was acceptable.

Constraints

  • Mission-critical usage: operators manage live network security through these screens
  • Legacy code with limited documentation, to be understood independently
  • Continuous delivery — modernization had to ride alongside normal releases
  • An external contractor role: high autonomy expected, low tolerance for hand-holding

My role

I built new admin screens end to end and independently deep-dived legacy areas to deliver fixes and harden infrastructure-adjacent components.

Approach

Modernize by strangler pattern, not rewrite

Hardened and replaced fragile pieces incrementally inside the live product, choosing seams where changes could ship safely release by release.

Read the legacy code before judging it

Invested in understanding why the existing infrastructure behaved as it did — most 'legacy problems’ encode real constraints, and breaking them creates incidents.

Propose UX and API improvements from the operator’s seat

Suggested backend interaction and UX changes that made high-frequency operational workflows clearer and faster, based on how the screens were actually used.

Result

  • New mission-critical admin screens shipped and used by global operations teams.
  • Legacy UI infrastructure made measurably more resilient without a delivery freeze.
  • A pattern of independent contract delivery inside a security-sensitive codebase.

Technologies

React · TypeScript · GraphQL · Legacy modernization

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