# Performance Tuning > Selected Engineer ApS work demonstrating Performance Tuning — the achievements that prove it. - [Directed full‑stack GIS map development, overseeing PostgreSQL, Mapbox, ReactJS, and NodeJS to deliver an integrated solution.](https://advisory.engineer.company/portfolio/directed-full-stack-gis-map-development-overseeing-postgresql-25/) - [Overhauled internal processes, saving 8,000 hours by improving software architecture, systems, and scheduling efficiency.](https://advisory.engineer.company/portfolio/overhauled-internal-processes-saving-8-000-hours-by-38/) - [Enhanced project efficiency, saving 150 hours per month across 30 projects by optimizing workflows and resource management.](https://advisory.engineer.company/portfolio/enhanced-project-efficiency-saving-150-hours-per-month-46/) - [Built the loyalty and reputation system — 67 functions over a 31‑table ledger, with leagues, badges and a redemption shop — taking a row lock on the balance to close the double‑spend window.](https://advisory.engineer.company/portfolio/built-the-loyalty-and-reputation-system-105/) - [Cut the site's browser‑driven quality gate from 1,636 seconds to 615 by scheduling its checks longest‑first through a worker pool bounded to four lanes, after measuring that alphabetical order cost 320 seconds against 224.](https://advisory.engineer.company/portfolio/cut-the-visual-quality-gate-to-ten-minutes-128/) - [Adopted Swift 6 complete strict concurrency with no actors, bridging a blocking C event loop to the main actor through one producer, one consumer and one ordering — after establishing that a task per event loses the ordering the interface depends on.](https://advisory.engineer.company/portfolio/adopted-swift-6-strict-concurrency-over-a-c-event-loop-156/) - [Took the test suite from six tests over a sixty‑second limit to 135 passing in 8.9 seconds by profiling the main thread and removing the two calls it sat inside for 3,989 samples out of 4,017.](https://advisory.engineer.company/portfolio/took-the-test-suite-under-nine-seconds-158/)