ViewOnPhone blog

Notes on responsive design, mobile testing and viewport sizes.

• How to test responsive design without a stack of phones2026-09-09 — A practical workflow for checking mobile layouts using viewport simulation, real-device spot checks and a short device matrix.
• Mobile viewport sizes that actually matter in 20262026-09-09 — Which widths to design and test for, why 360–430px covers most traffic, and the tablet and foldable edge cases worth a look.
• Viewport width vs device pixel ratio: what your layout responds to2026-09-09 — CSS pixels, hardware pixels and DPR explained — and why a preview tool that matches the viewport is enough for layout QA.