Simon Willison’s Weblog

viewport-preview (via) I built a tiny tool which lets you preview a URL in a bunch of different common browser viewport widths, using iframes.

Posted 26th July 2022 at 12 am

Recent articles

Reverse engineering some updates to Claude - 31st July 2025
Trying out Qwen3 Coder Flash using LM Studio and Open WebUI and LLM - 31st July 2025
My 2.5 year old laptop can write Space Invaders in JavaScript now, using GLM-4.5 Air and MLX - 29th July 2025

css 229 iframes 21 mobile 40 projects 494 testing 62

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