Technical Specifications of Grok-4.3
| Item | Grok-4.3 |
|---|---|
| Model ID | grok-4.3 |
| Provider | xAI |
| Release date | April 30, 2026 |
| Model type | Reasoning-focused LLM |
| Input types | Text, Image |
| Output types | Text |
| Context window | 1,000,000 tokens |
| Knowledge cutoff | December 2025 |
| Key capabilities | Reasoning, tool use, function calling, multimodal, structured outputs |
| API access | Yes (console, API, CLI) |
| Reasoning | Yes, xAI says “The model thinks before responding.” |
| Rate limits | 1,800 requests/minute; 10,000,000 tokens/minute |
What Grok 4.3 is
Grok 4.3 is xAI’s reasoning-focused Grok model for production API work where long context, external tools, and structured answers matter. Explicitly recommends it as the replacement for several older Grok 4 and Grok 3-era reasoning models, and says it delivers improved agentic coding and web development capability.
Main features
1) Agentic tool use
Grok 4.3 supports function calling, which lets it connect to external tools, APIs, and systems. This matters for workflows like database lookups, internal search, calculations, ticket routing, and multi-step automation. xAI’s function-calling docs also show that the model can return multiple tool calls in a single response when parallel calling is enabled.
2) Structured outputs
xAI lists structured outputs as a native capability, which makes the model easier to integrate into software pipelines where a predictable JSON schema or a fixed response format is important.
3) Long-context reasoning
With a 1M-token context window, Grok 4.3 is designed for large documents, long conversations, codebases, and multi-file analysis. xAI also notes special pricing for requests that exceed the 200K context threshold, which signals that the model is expected to handle very large prompts in production settings.
- Artificial Analysis Intelligence Index: Score ~53, well above average (~35)
- Global ranking: Top-tier (#10–#11 among evaluated models)
- Speed: ~100 tokens/sec (above median)
👉 Interpretation: Grok-4.3 is a frontier-level reasoning model, competitive with top-tier models in logic, coding, and structured reasoning tasks.
Grok 4.3 vs GPT 5.5 vs Claude 4.6
| Model | Positioning | Context window | Input / output pricing | Notable strengths |
|---|---|---|---|---|
| Grok 4.3 | xAI flagship for agentic reasoning and tool use | 1M | $1.25 / $2.50 per 1M tokens | Function calling, structured outputs, three reasoning levels, strong price-performance. |
| Grok 4.20 reasoning | xAI’s larger-context reasoning option | 2M | $1.25 / $2.50 per 1M tokens | Bigger context than Grok 4.3, still aimed at reasoning-heavy use. |
| OpenAI GPT-5.5 | OpenAI flagship for complex reasoning and coding | 1M | $5 / $30 per 1M tokens | Text and image input, web search, file search, computer use. |
| Anthropic Claude Sonnet 4.6 | Anthropic’s speed-intelligence balance model | 1M on API beta | $3 / $15 per 1M tokens | Extended thinking, adaptive thinking, broad platform availability. |
Grok-4.3 is best when reasoning quality + large context + tool use matter more than ultra-low latency.
Best-fit use cases for Grok 4.3(Alternative of Grok code fast )
- Long-form assistant workflows that need memory across many turns.
- Internal copilots that must call tools, return JSON, and keep a strict schema.
- Coding assistants for refactors, debugging, and web-dev tasks.
- Research assistants that combine model reasoning with live search tools.
- Workflow automation agents that need consistent instruction following.
How to access and use Grok 4.3 API
Step 1: Sign Up for API Key
Log in to cometapi.com. If you are not our user yet, please register first. Sign into your CometAPI console. Get the access credential API key of the interface. Click “Add Token” at the API token in the personal center, get the token key: sk-xxxxx and submit.
Step 2: Send Requests to Grok 4.3 API
Select the “grok-4.3” endpoint to send the API request and set the request body. The request method and request body are obtained from our website API doc. Our website also provides Apifox test for your convenience. Replace <YOUR_API_KEY> with your actual CometAPI key from your account. Where to call it: Chat format.
Insert your question or request into the content field—this is what the model will respond to . Process the API response to get the generated answer.
Step 3: Retrieve and Verify Results
Process the API response to get the generated answer. After processing, the API responds with the task status and output data.