Systems Architecture & Engineering

Bridging high-level design with low-level, battle-tested implementations.

For over 18 years, software I designed has powered billions of sessions for millions of developers; running alongside systems where I never see the underlying source code. No specs, no hand-holding: just fast, reproducible engineering.

See the benchmarkshi@kohl.gg
Lazy propagationtry it
SIGNALDERIVEDEFFECTprice40qty3sum120tax10ui$130ship—watchoffno observerdirty bitrecomputed

ran 0 · skipped 0

idlenothing is dirty · write a signal to start

Built in the Open.

The engines, platforms, and primitives behind those billions of sessions: source you can read, numbers you can rerun.

library

Flux

A lazy reactivity engine and UI framework. Computations run only when observed, so a write costs the flag, not the recompute. No dirty-checking, no topological sorts, and no virtual DOM. Strictly typed to catch misuse before the code executes.

  • Luau
  • Reactivity
  • Typed API
  • CI + Coverage
platform

Kohl's Admin

Live-ops infrastructure for Roblox experiences: role-based access, live moderation, anti-abuse, and monetization behind a version-stable API.

  • Luau
  • RBAC
  • Live Ops
  • API Stability
method

Luau reactivity benchmark

A port of js-reactivity-benchmark. Upstream abandoned their GC suite, so I wrote one that measures teardown cost and retention across 60k-node graphs.

  • Luau
  • Python
  • Measurement
  • Reproducible CI
algorithm

HyperLogLog

HyperLogLog++: counts millions of distinct values in a few kilobytes of fixed memory, and its sketches merge across servers without double-counting.

  • Luau
  • Cardinality
  • Probabilistic
  • Distributed

O(1) inserts
tunable precision

Source
wire format

Z

Schema-driven binary serialization: varints, bit-packed booleans, and lossy fixed-point types; every value pays for only the bits it needs.

  • Luau
  • buffers
  • protocol design
  • schema migration

varint + bit-packed
migratable schemas

Source

Identical workloads. Measured.

Flux is mine. The other bars are the ecosystem's three most popular fine-grained reactivity libraries, plus Roblox's official one. The workloads aren't mine: the harness is a straight port of js-reactivity-benchmark.

Luau reactivity benchmarkheadless luau -O2· per-bench process isolation · normalised per row to the fastest (shorter = faster)1×2×4×6×8×10×relative time, lower is faster →OVERALL · GEOMETRIC MEANover 22 of 22 rows · DNF charged its per-bench time capkohltastrophe/flux0.1.01.08×centau/vide0.4.01.32×roblox/signals0.9.01.66×littensy/charm0.11.01.73×elttob/fusion0.3.014.84×Port of milomg/js-reactivity-benchmark · normalised per row to the fastest framework (1.0×, shorter = faster) · process-isolated, fastest-of-N per run.Faded bars exceed 10× (true multiple labelled) · a DNF is charged its benchmark's time budget (per-bench cap, else the 60s process cap) in the geomean (an unexpected error is excluded instead).

Geometric mean across the kairo, cellx, dynamic, sbench, and GC suites, each library configured as shipped. Method, adapters, and raw numbers: luau-reactivity-benchmark.

How I work. With receipts.

Three principles, each ending in the code that holds me to it.

01

Write the missing spec

Ambiguity is expensive, so hard definitions come first: what to measure, what must be fast, and what counts as done.

receipt

Upstream started a GC suite and never finished it, so I wrote the spec myself.

the measurement
02

Build for the dark

Production, for me, is other people's servers: no console, no logs, no second chances. Anything that can fail is handled before it ships.

receipt

One release lands on millions of live servers at once. Strict versioning is the only rollback I get.

the solution
03

Ship the proof

Recent client work is under NDA, so the open repositories stand in for it. Nothing on this page asks to be taken on trust.

receipt

Five repositories, MIT licensed, benchmarks included. Audit the commit history, not the résumé.

the work

Let's connect.

I'm always open to discussing new collaborations, complex technical challenges, or interdisciplinary projects.

hi@kohl.ggGitHub
At a glancelimited slots open
Experience
18 Years · Product · Systems
Focus
Live Ops · Protocols · Reactivity
Languages
Luau · C/C++ · Java · JS · Python · SQL
Also
Blender · After FX · Illustrator · Photoshop