Claude Opus 5.5
The newest Claude flagship, for hard reasoning, long documents and large codebases.
Model IDclaude-opus-5-5
Good for
- Step-by-step analysis, planning and research
- Book-length documents: contracts, reports, transcripts
- Large refactors in Claude Code
Context window1,000,000 tokens
CategoryText
Credit rates
| Type | Credits | About |
|---|---|---|
| Inputper 1M tokens | 252,868 | HK$25.29 |
| Outputper 1M tokens | 1,264,340 | HK$126.43 |
10,000 credits = HK$1. Credits come with your monthly plan and each request is charged by what it uses. Every request is itemised under Usage in the console.
Which plans include it
| Plan | Included | Per month, roughly (messages) |
|---|---|---|
| Taster HK$28 | ✓ | ≈ 141 |
| Everyday HK$128 | ✓ | ≈ 564 |
| Advanced HK$288 | ✓ | ≈ 1,468 |
| Professional HK$588 | ✓ | ≈ 3,162 |
Monthly counts assume the whole month goes to this one use; chat, images and video share one credit pool. Compare plans →
How to use it
Through the API
Create an API key in the console, then call it by its model ID:
curl https://api.essevin.com/v1/messages \
-H "x-api-key: $ESSEVIN_API_KEY" \
-H "anthropic-version: 2023-06-01" \
-H "content-type: application/json" \
-d '{
"model": "claude-opus-5-5",
"max_tokens": 1024,
"messages": [{"role": "user", "content": "Hello"}]
}'More in this family
Claude Sonnet 5.5NewThe newest Sonnet: quality and speed together, the everyday model for writing and code.886 credits / messageClaude Haiku 5.5NewThe newest Haiku: fast and light on credits, for lots of short requests.45 credits / messageClaude Fable 5.1NewThe top Claude tier, for the hardest work that deserves the most care.4,426 credits / messageClaude Sonnet 5The previous Sonnet, priced like Sonnet 5.5 and kept for existing workflows.886 credits / messageClaude Haiku 4.5The previous Haiku: fast and light for high-volume simple tasks.443 credits / messageClaude Fable 5The previous Fable release, kept for existing workflows.4,426 credits / message