Claude Opus 4.8 (Fast)
Fast-mode variant of [Opus 4.8](/anthropic/claude-opus-4.8) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 4.8. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode
Context window
This model accepts 1M tokens in one request (~750K words of text).
What fits in one request
- FitsShort documentAbout 1,500 words of text
- FitsLong documentAbout 37K words of text
- FitsSmall codebaseAbout 150K words of text
- FitsFull novelAbout 375K words of text
Specifications
Context size, pricing, and release info in one place.
- Context window
- 1,000,000 tokens (1M)
- Max output tokens
- 128,000 tokens (128K)
- Speed tier
- deep
- Provider
- Anthropic
- Model family
- Claude Opus
- Release date
- May 2026
Capabilities
See which features this model supports, such as vision, tools, and streaming.
- Vision
- Accepts image inputs alongside text
- Supported
- Tool use
- Can call external tools and APIs
- Supported
- Function calling
- Structured function call interface
- Supported
- Extended thinking
- Shows its chain-of-thought reasoning
- Supported
- Streaming
- Returns tokens as they are generated
- Supported
- Batch API
- Process many requests asynchronously
- Supported
- Prompt caching
- Reuse repeated prompt prefixes cheaply
- Supported
- Web search
- Can browse the web during a request
- Not supported
Best for
Jump to a guide or ranking that matches each workload.
Compare Claude Opus 4.8 (Fast)
Open a side-by-side comparison with one click.
- Claude Opus 4.8 (Fast) vs Jp Anthropic Claude Sonnet 4 6
Same context window size
- Claude Opus 4.8 (Fast) vs Claude Sonnet 4 6
Same context window size
- Claude Opus 4.8 (Fast) vs Amazon Titan Text Express
Claude Opus 4.8 (Fast) has 2280% larger context window
- Claude Opus 4.8 (Fast) vs Amazon Titan Text Premier
Claude Opus 4.8 (Fast) has 2280% larger context window
- Claude Opus 4.8 (Fast) vs Amazon Titan Text Lite
Claude Opus 4.8 (Fast) has 2280% larger context window
- Claude Opus 4.8 (Fast) vs Apac Amazon Nova 2 Lite
Same context window size
Frequently asked questions
Short answers about context size and how this model behaves.
More from Anthropic
Other models by Anthropic in our catalog.
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