Anthropic ships Claude Sonnet 5.5: 30% faster, up to 30% cheaper for most workloads
ClaudeDevs · x · 2026-09-29
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family after Opus 5.5, alongside an official developer guide.
- Smarter and more efficient than Sonnet 5, 30% faster, with unchanged per-token pricing; since it typically needs far fewer tokens for the same work, most tasks cost up to 30% less.
- It thinks by default: responses may start with a thinking block, so code reading content[0].text breaks — the guide includes a minimal example with outputconfig={"effort": "medium"}.
- When to choose what: Sonnet 5.5 for well-scoped everyday coding (bug fixes, feature iteration) and polished docs/slides/spreadsheets; Opus 5.5 for tasks needing careful judgment; Haiku 5.5 arrives in the coming weeks for high-volume, low-latency workflows.
- The guide also covers migrating from Sonnet 5, tuning effort, and using the model in Claude Code.
Related event: Anthropic Launches Claude Sonnet 5.5: Over 30% Faster, Up to 30% Cheaper(58 posts)→
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