Chat with Grok 4 for free
Grok 4 pairs realtime knowledge with a direct, witty tone and live web search, strong on current events and fresh information. Start typing, no sign-up needed.
See how Grok 4 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 Grok 4 stand out
Grok 4 specifications
| Provider | xAI |
| Model family | Grok 4 series |
| Context window | 1,000,000 tokens |
| Max output | 1,000,000 tokens |
| Modality | Text · Vision · Code |
| Input price | $0.2 / 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.
Grok 4 vs other top models
| Model | Context | Best at | Input price | In Chatday |
|---|---|---|---|---|
| Grok 4 | 1M | Realtime | $0.2/M | Free |
| Claude Opus 4.8 | 1M | Frontier coding | $5/M | Free |
| GPT-5.5 | 1M | Flagship reasoning | $5/M | Free |
| Gemini 3.1 Pro | 1M | Multimodal | $2/M | Free |
Grok 4 questions
Other models
Claude Opus 4.8
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GPT-5.5
GPT-5.5 is OpenAI's flagship model for hard, multi-step reasoning, coding and tool use, the default when problems get genuinely difficult.
Gemini 3.1 Pro
Gemini 3.1 Pro is natively multimodal across text, image, audio and video, with the largest context window available and fast, fresh answers.
Chat with Grok 4 and switch models any time.
One subscription, every leading model. Start free in the Chatday web app.