Interactive learning01 / 03
SortPedia
Explore 30+ sorting algorithms through step-by-step visualisation, side-by-side races, and browser-based benchmarks.
David Young / Software engineer & builder
I build systems you can reason about.
Full stack engineer working across product, data, and infrastructure. This is a place to explore the decisions behind dependable software—and try a few of them yourself.
Systems, in motion
Requestuser intent
Applicationvalidate + persist
durable boundary
Job ledgerretry safely
Databasesource of truth
01source of truth
∞safe retries
0silent losses
A principle, not a production diagram.
01 / Engineering playground
Learn by changing the system.
Six connected experiments from safe retries to full-system design practice.
Follow the learning path ↗Failure simulator01
Retry & Idempotency Lab
Crash a worker after a provider call. Replay delivery and see how durable claims and idempotency keys change the outcome.
Systems sandbox02
Cache Correctness Lab
Route requests between instances, then run continuous traffic to see hits, misses, hot keys, and stale decisions.
Decision playground03
Data Store Decision Lab
Compare six storage models against one workload. Mutate sample data, run an access path, and inspect load-sensitive tradeoffs.
Linked calculator04
Capacity Planner Lab
Turn users into peak traffic, app instances, database work, connection demand, cache memory, and storage.
Architecture walkthrough05
System Evolution Lab
Grow an architecture through seven stages. Inject traffic and failures to see what each step fixes and what it adds.
Practice generator06
Design Practice Lab
Generate a product, scale, and hard constraint. Sketch a design, reveal hints when needed, and test your own explanation.
02 / Selected work
Built to leave the prototype stage.
A few public projects that span interactive learning, engineering tools, and useful everyday software.
All projects ↗Mobile product02 / 03
RainVu
A local-first rainfall journal with offline storage, history, and clear analytics for growers and weather watchers.
Engineering research03 / 03
FERS
Modernising a signal-level radar simulator with a C++23 core and a desktop interface for building scenarios.
03 / How I think
Good systems make their rules visible.
Patterns drawn from building and improving real services. Each one is a question worth asking before adding more machinery.
Where does the answer live?
Keep authoritative state in a durable store. Let caches make reads faster without deciding what is true.
What happens on the second try?
Persist intent, bound work, and design every side effect for retries before the first outage asks the question.
What would prove this works?
Compare independent results, inspect real query plans, and test capacity against the actual bottleneck.
04 / Experience
Product work, end to end.
Yoco
Building Dyner at Yoco: an AI-native operating system for restaurants and independent businesses.
astraen
Building independent software projects and technical foundations for product ideas.
The DataFlow
Co-founded and led engineering for a mobile app that helped users monitor and control mobile data usage.
05 / Writing
Notes from the build process.
Have a good problem?
Let’s make something useful.
Open to conversations about product engineering, systems, and ambitious ideas worth building carefully.