Building with Claude Sonnet 5.5

When to choose Sonnet over Opus, what it costs, and how to tune it. Claude Sonnet 5.5 is our second model in the Claude 5.5 family after Opus 5.5. It's a clear upgrade over Sonnet 5 and is smarter, more efficient and 30% faster. The per-token price is unchanged and because Sonnet 5.5 typically needs far fewer tokens to do the same work, it costs up to 30% less for most work. Credit to @jkeatn for ideas related to code-to-painting and @IceSolst for the reference image. This guide is about building with the model.

Published by Claude Blog. This page is a short excerpt; the full text is theirs.