Claude Sonnet: the workhorse model developers love

2025

While Opus grabbed headlines with benchmark scores, it was Sonnet that won developers' hearts. Fast, affordable, and surprisingly capable, it became the default model for production applications.

The reasoning was simple economics. Opus was brilliant but expensive and slower. Haiku was cheap but limited. Sonnet sat in the middle: smart enough for 90% of tasks, fast enough for real-time applications, and priced for scale.

Startups built entire products on Sonnet. Customer support bots, code review tools, content moderation systems, data analysis pipelines: all running on a model that cost a fraction of what Opus would.

Developers appreciated that Sonnet didn't just trade quality for speed. It maintained Claude's signature characteristics: honesty, careful reasoning, and a lack of sycophancy. It would still push back when asked to do something questionable, still say "I'm not sure" when uncertain.

The lesson for the industry was clear: the best model isn't always the biggest one. It's the one that fits your use case, your budget, and your latency requirements. And for most of the world, that's Sonnet.