Every screenshot in my dev.to posts has the same caption: "All tests run on an 8-year-old MacBook Air."
That's not a disclaimer. It's a design constraint.
The machine
2017 MacBook Air. 1.8GHz dual-core Intel Core i5. 8GB RAM. No discrete GPU. No Apple Silicon neural engine. The slowest Mac you could reasonably use in 2026.
This is my primary development and testing machine.
What it breaks immediately
Anything that renders everything at once.
Loading a 200-page PDF and rendering all pages to images: the app freezes. This is how I discovered I needed virtual scrolling. The problem was invisible on modern hardware — which means I would have shipped a broken experience to half my users if I'd developed on a fast machine.
Synchronous operations on the main thread.
On fast hardware, 200ms is invisible. On this machine, it's a visible stutter. Everything that takes more than a few milliseconds lives in a background thread — not as best practice, but because the 2017 Air demanded it.
Memory-heavy caches.
Aggressive page caching on 8GB RAM (with macOS taking 4GB) causes memory compression, which causes stutters worse than the cache was helping. The constraint forced a smarter eviction policy.
What the constraint produced
Ghost Engine.
The resident daemon architecture came directly from 50ms process-spawn overhead being noticeable on this machine. On modern hardware you might not feel 50ms. On a 2017 i5 you feel every millisecond.
Turbo View Engine.
Virtual scrolling, Ghost Batch, Intelligent Prefetch — all emerged from "this must not freeze on a 7-year-old dual-core."
Lean dependencies.
Every crate gets benchmarked on this machine. If it slows cold start by more than 100ms, I look for an alternative. The dependency list stays short.
The actual benefit
Apps that run well on a 2017 MacBook Air run well on everything.
The users who most need a good PDF tool are disproportionately likely to be on older hardware. Building for the constraint means building for them.
The recommendation
Find the oldest hardware your target users might reasonably have. Make it your test machine.
Not as a checkbox. As a design input.
The constraints it surfaces are the constraints that actually matter.
Hiyoko PDF Vault → https://hiyokoko.gumroad.com/l/HiyokoPDFVault
X → @hiyoyok