Claude Sonnet 5.5
by Anthropic
Claude Sonnet 5.5 is Anthropic's latest Sonnet-series language model, released September 28, 2026. It is positioned as a faster and lower-cost complement to Claude Opus 5.5, optimized for everyday professional tasks, bug fixing, and document creation. Pricing is $2 per million input tokens and $10 per million output tokens.
Large Language Models
Proprietary
Primary Use Cases
- Professional writing and document creation
- Software bug fixing and code review
- Everyday business tasks requiring fast turnaround
- Cost-sensitive production deployments
✅ Strengths
- Lower cost than Opus 5.5 at $2/$10 per million tokens
- Faster inference than Opus-class models
- Backed by Anthropic safety evaluations (system card published)
⚠️ Limitations
- Less capable than Claude Opus 5.5 on complex long-horizon agentic tasks
- 1M-token context window not confirmed for Sonnet 5.5 (confirmed for Opus 5.5)
Technical Specifications
Developer
Anthropic
Category
Large Language Models
Type
🧠 Foundation Model
License
UNKNOWN
Version
Sonnet 5.5
Trust & Privacy
Health Status
🟢 Active
Trains on User Data
🔄 Opt-out available
Certifications
None listed
Ecosystem & Integrations
API Access
✅ Available
Chrome Extension
❌ No
Mobile App
❌ No
Pricing Model
💰 Pay Per Use
Pricing Breakdown
API
Pay-per-use API access
Input$2/M tokens
Output$10/M tokens