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Serhii Kuznetsov

Notes

Bugs worth writing down

Write-ups of bugs and decisions from my projects: what broke, how I measured it, and what fixed it. Each one has the numbers, because “it felt faster” is not a result.

  1. 5 min read

    Two windows, one client id

    A shared whiteboard where one window's edits reached nobody. The protocol was right and its tests were green — the browser had copied something I had assumed belonged to a single tab.

    • Realtime
    • Browser storage
    • Debugging

  2. 5 min read

    The refusal that named nothing

    A change the room threw away stayed queued for ever: its author kept seeing an edit no one else had. Fixing it was less about the limits than about what a refusal has to carry.

    • Realtime
    • Protocol design
    • Testing

  3. 4 min read

    The lag my test browser could not see

    Headless Chrome draws at 60 fps whatever the monitor. On a 165 Hz screen that hid a 146 ms frame — and the CSS property behind it was one I had decided was free.

    • Performance
    • CSS
    • Measuring

  4. 3 min read

    AnimatePresence and the pages that went blank

    An exit animation in the App Router left 30 of 40 pages at opacity: 0 — header and footer on screen, content invisible, and nothing a text search could find.

    • Next.js
    • Framer Motion
    • Debugging