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Home/Models/xAI/Grok 4.3
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Grok 4.3

Input:$1/M
Output:$2/M
Excels at agentic reasoning, knowledge work, and tool use.
New
Commercial Use
Playground
Overview
Features
Pricing
API

Technical Specifications of Grok-4.3

ItemGrok-4.3
Model IDgrok-4.3
ProviderxAI
Release dateApril 30, 2026
Model typeReasoning-focused LLM
Input typesText, Image
Output typesText
Context window1,000,000 tokens
Knowledge cutoffDecember 2025
Key capabilitiesReasoning, tool use, function calling, multimodal, structured outputs
API accessYes (console, API, CLI)
ReasoningYes, xAI says “The model thinks before responding.”
Rate limits1,800 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

ModelPositioningContext windowInput / output pricingNotable strengths
Grok 4.3xAI flagship for agentic reasoning and tool use1M$1.25 / $2.50 per 1M tokensFunction calling, structured outputs, three reasoning levels, strong price-performance.
Grok 4.20 reasoningxAI’s larger-context reasoning option2M$1.25 / $2.50 per 1M tokensBigger context than Grok 4.3, still aimed at reasoning-heavy use.
OpenAI GPT-5.5OpenAI flagship for complex reasoning and coding1M$5 / $30 per 1M tokensText and image input, web search, file search, computer use.
Anthropic Claude Sonnet 4.6Anthropic’s speed-intelligence balance model1M on API beta$3 / $15 per 1M tokensExtended 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.

FAQ

Can Grok-4.3 API handle extremely long documents?

Yes, Grok-4.3 supports a 1,000,000 token context window, enabling it to process entire codebases or large document collections in a single request.

How does Grok-4.3 API compare to Grok-4.20?

Grok-4.3 offers stronger reasoning, instruction-following, and tool use, while Grok-4.20 provides a larger 2M token context window for ultra-long inputs.

Is Grok-4.3 a multimodal model?

Yes, Grok-4.3 accepts both text and image inputs and generates text outputs for analysis and reasoning tasks.

What makes Grok-4.3 suitable for agent-based workflows?

It includes built-in reasoning, function calling, and tool-use capabilities, allowing it to execute multi-step tasks and structured workflows reliably.

How does Grok-4.3 perform on benchmarks?

Grok-4.3 scores around 53 on the Artificial Analysis Intelligence Index, placing it well above average and among top-tier models.

What are the main limitations of Grok-4.3 API?

Its main limitations include higher latency, verbose outputs that increase cost, and the need for real-world testing in production environments.

Is Grok-4.3 API good for coding and scientific tasks?

Yes, it is specifically optimized for advanced reasoning, making it highly effective for coding, mathematics, and scientific analysis.

What is the knowledge cutoff for Grok-4.3?

Grok-4.3 has a knowledge cutoff of December 2025.

Features for Grok 4.3

Explore the key features of Grok 4.3, designed to enhance performance and usability. Discover how these capabilities can benefit your projects and improve user experience.

Pricing for Grok 4.3

Explore competitive pricing for Grok 4.3, designed to fit various budgets and usage needs. Our flexible plans ensure you only pay for what you use, making it easy to scale as your requirements grow. Discover how Grok 4.3 can enhance your projects while keeping costs manageable.
Comet Price (USD / M Tokens)Official Price (USD / M Tokens)Discount
Input:$1/M
Output:$2/M
Input:$1.25/M
Output:$2.5/M
-20%

Sample code and API for Grok 4.3

Access comprehensive sample code and API resources for Grok 4.3 to streamline your integration process. Our detailed documentation provides step-by-step guidance, helping you leverage the full potential of Grok 4.3 in your projects.
POST
/v1/chat/completions
Python
JavaScript
Curl
from openai import OpenAI
import os

# Get your CometAPI key from https://www.cometapi.com/console/token, and paste it here
COMETAPI_KEY = os.environ.get("COMETAPI_KEY") or "<YOUR_COMETAPI_KEY>"
BASE_URL = "https://api.cometapi.com/v1"

client = OpenAI(base_url=BASE_URL, api_key=COMETAPI_KEY)

completion = client.chat.completions.create(
    model="grok-4.3",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Hello!"},
    ],
)

print(completion.choices[0].message.content)

Python Code Example

from openai import OpenAI
import os

# Get your CometAPI key from https://www.cometapi.com/console/token, and paste it here
COMETAPI_KEY = os.environ.get("COMETAPI_KEY") or "<YOUR_COMETAPI_KEY>"
BASE_URL = "https://api.cometapi.com/v1"

client = OpenAI(base_url=BASE_URL, api_key=COMETAPI_KEY)

completion = client.chat.completions.create(
    model="grok-4.3",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Hello!"},
    ],
)

print(completion.choices[0].message.content)

JavaScript Code Example

import OpenAI from "openai";

// Get your CometAPI key from https://www.cometapi.com/console/token, and paste it here
const COMETAPI_KEY = process.env.COMETAPI_KEY || "<YOUR_COMETAPI_KEY>";
const BASE_URL = "https://api.cometapi.com/v1";

const client = new OpenAI({
  apiKey: COMETAPI_KEY,
  baseURL: BASE_URL,
});

async function main() {
  const completion = await client.chat.completions.create({
    model: "grok-4.3",
    messages: [
      { role: "system", content: "You are a helpful assistant." },
      { role: "user", content: "Hello!" },
    ],
  });

  console.log(completion.choices[0].message.content);
}

main();

Curl Code Example

#!/bin/bash
# Get your CometAPI key from https://www.cometapi.com/console/token, and paste it here

curl "https://api.cometapi.com/v1/chat/completions" \
  -H "Authorization: Bearer $COMETAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4.3",
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "Hello!"}
    ]
  }'

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