Chat with Claude Haiku 5.5 for free
Claude Haiku 5.5 is Anthropic's fastest and cheapest Claude, with adjustable effort, a 1M-token context and solid coding for high-volume work. Start typing, no sign-up needed.
See how Claude Haiku 5.5 thinks
Pick a task and watch a sample answer stream in. Open the same prompt in Chatday when you’re ready.
The bug is in the arrow body: u.id = id assigns instead of compares, so the callback returns the assigned value and .find never matches the way you expect.
Fix it with a strict comparison:
Use === to compare. A single = is assignment, which is why you saw undefined.
What makes Claude Haiku 5.5 stand out
Claude Haiku 5.5 specifications
| Provider | Anthropic |
| Model family | Claude 5 series |
| Context window | 1,000,000 tokens |
| Max output | 128,000 tokens |
| Modality | Text · Vision · Code |
| Input price | $0.1 / 1M tokens |
| Output price | $0.5 / 1M tokens |
| Tool / function calling | Yes |
| Vision | Yes |
| Streaming | Yes |
| Available in Chatday | Free & Pro |
Pricing shown for reference; usage is included in your Chatday plan.
Claude Haiku 5.5 vs other top models
| Model | Context | Best at | Input price | In Chatday |
|---|---|---|---|---|
| Claude Haiku 5.5 | 1M | Fast & affordable | $0.1/M | Free |
| GPT-6.1 | 1.1M | Agentic coding | $2/M | Free |
| Grok 4.6 | 500K | Agentic reasoning | $2/M | Free |
| Gemini 3.1 Pro | 1M | Multimodal | $2/M | Free |
Claude Haiku 5.5 questions
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Claude Opus 5
Claude Opus 5 is Anthropic's strongest Opus model: hybrid reasoning for long-running agents, serious coding and computer use.
Chat with Claude Haiku 5.5 and switch models any time.
One subscription, every leading model. Start free in the Chatday web app.