Real-time Routing & Isoline Service
Performance tuning and RPA test automation for HERE's routing APIs.
High
availability SLOs met
RPA
test suites automated
The problem
Routing and isoline calculations are latency-critical and CPU-heavy. Test coverage for geographic edge cases (tunnels, toll roads, restricted zones) was manual and flaky.
Approach
- Profiled hot paths in the routing service; pushed expensive geometry ops into Rust modules.
- Automated regression suites via RPA — replaying canonical trips across regions.
- Tuned Kubernetes HPA + node pools to keep SLOs under burst traffic.
Key decisions
Rust for hot paths, not rewrites
Full rewrites stall. Replacing only the CPU-dominant functions gave 80% of the wins at 20% of the risk.
Trade-offs
- Polyglot stack adds operational surface — invested in consistent observability to compensate.
Impact
- Meaningful latency improvement on hot routing paths.
- Test flakiness dropped; release confidence up.
Let's build
Have a system that needs to scale — or stop breaking?
I work with a small number of teams each month on architecture reviews, scaling, and hands-on backend engineering. If that sounds like you, let's talk.