Simon Willison’s Weblog

Could Rails have been built without Ruby? Fascinating essay about how Ruby, like Lisp, lets you build new languages.

Posted 15th April 2005 at 5:42 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

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe