Anthropic · Fast / lightweight
Claude Sonnet 4.5 deprecation Deprecated
Retirement on the Claude API 2026-11-30; replacement claude-sonnet-5-5
- Provider
- Anthropic
- Family
- Claude
- Model type
- Fast / lightweight
- Official release date
- Sep 30, 2026
- Release type
- Deprecation
- Status
- Deprecated
- Previous version
- —
- Input
- text
- Output
- text
- Context window
- Not documented
- Max output
- Not documented
- API model id
claude-sonnet-4-5-20250929- API price (input)
- Not verified
- API price (output)
- Not verified
- Price notes
- —
- Consumer apps
- —
- Developer API
- —
- Free access
- None documented
- Paid access
- —
- Availability
- —
- Licence
- proprietary
Main improvements
- Retirement on the Claude API 2026-11-30; replacement claude-sonnet-5-5
- Also retired in 2026: Opus 4 and Sonnet 4 (2026-06-15), Opus 4.1 (2026-08-05), Haiku 3 (2026-04-20)
Benchmarks
No benchmark results recorded. We only list scores with a source, benchmark version and date.
More from Anthropic
- Claude Haiku 5.5 Generally available · Oct 7, 2026
- Claude Sonnet 5.5 Generally available · Sep 28, 2026
- Claude Opus 5.5 Generally available · Sep 22, 2026
- Claude Fable 5.1 Generally available · Sep 1, 2026
- Claude Mythos 5.1 Generally available · Sep 1, 2026