Simon Willison’s Weblog

Hex Fiend. Hex editor for OS X. I could have done with this a few weeks ago.

Posted 28th March 2006 at 10:11 pm

Recent articles

GPT-5: Key characteristics, pricing and model card - 7th August 2025
OpenAI's new open weight (Apache 2) models are really good - 5th August 2025
ChatGPT agent's user-agent - 4th August 2025

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