Grok 4.3: Complete Specifications, Pricing, API Access & Use Cases (2026)

What Is Grok 4.3?

Grok 4.3 is xAI’s multimodal reasoning model for text and image input with text output, listed in xAI’s developer documentation by May 2026, featuring a 1,000,000-token context window and configurable reasoning, with API pricing from \$1.25 per 1M input tokens and \$2.50 per 1M output tokens as of July 2026.

xAI lists Grok 4.3 as a flagship general-purpose model in the Grok 4 family. Its documented strengths include agentic tool calling, instruction following, structured outputs, and configurable reasoning levels.

Grok 4.3 is especially relevant to developers evaluating long-context AI systems, multimodal assistants, tool-using agents, structured extraction workflows, and production applications where context length, pricing, model ID, and API compatibility must be clear before deployment.

What Are Grok 4.3’s Key Specifications and Pricing?

What Can Grok 4.3 Do That Makes It Useful in Production?

Long-context analysis. Grok 4.3’s documented 1,000,000-token context window makes it relevant for large-document review, multi-file analysis, long conversations, and retrieval-augmented systems that need more context in a single request. Teams should still manage cost and latency carefully because xAI documents different pricing for requests beyond the 200K context window.

Configurable reasoning. Grok 4.3 supports the reasoning_effort parameter, allowing developers to choose how much effort the model spends before responding. xAI documents supported effort levels and notes that some parameters, including presencePenalty, frequencyPenalty, and stop, cannot be used with reasoning models.

Tool-using agent workflows. Function calling allows Grok 4.3 to connect with external tools and systems. This is useful for support automation, workflow orchestration, internal copilots, and agentic applications where the model must call APIs instead of only producing prose.

Structured output workflows. Structured outputs make Grok 4.3 relevant for extraction, classification, routing, form filling, and analytics workflows that need predictable response formats. Production systems should still validate responses, enforce schemas, and implement retries or fallback handling.

Multimodal understanding. Grok 4.3 supports text and image input with text output, which can help with visual question answering, screenshot interpretation, document-image review, UI analysis, and image-grounded support tasks. Native video input and native PDF, PPTX, or XLSX file generation are not confirmed in the reviewed xAI model documentation.

What Are Grok 4.3’s Supported Modalities?

Where Does Grok 4.3 Fall Short?

Several model-specific details remain incomplete in public documentation. The exact public release date, Grok 4.3-specific knowledge cutoff, fine-tuning support, license restrictions, and model-specific batch API behavior were not confirmed from official sources as of July 2026.

Cost planning requires attention. xAI documents baseline token prices and notes higher-context pricing beyond 200K context, while Gate.AI listing details for this model page show separate pricing tiers for requests at or below 200K and above 200K context. Teams should estimate cost using realistic prompt sizes, cached-token usage, output length, and retry behavior rather than relying only on headline input pricing.

This is a general AI limitation and is not model-specific unless stated by xAI: Grok 4.3 may produce incorrect, incomplete, outdated, or unsupported outputs. Human review is required for legal, medical, financial, security, hiring, compliance, and other high-stakes workflows.

The model should not be treated as a replacement for all xAI products. xAI’s documentation separates general Grok models from specialized resources such as voice, image, and video workflows, so developers should choose the endpoint that matches the required modality and output format.

What Is Grok 4.3 Best Used For?

How Does Grok 4.3 Compare to Claude Sonnet 5 and Gemini 3.5 Flash?

Grok 4.3, Claude Sonnet 5, and Gemini 3.5 Flash should be evaluated by workload rather than ranked as a single overall winner. Grok 4.3 is especially relevant when a 1M-token context window, configurable reasoning, function calling, and image input are important. Competitor specifications should be refreshed from their official sources before procurement or production selection.

How Do I Access Grok 4.3 Through Gate.AI?

Gate.AI documents an OpenAI-compatible API format with the base URL https://api.gate.ai/openai/v1. The Gate.AI listing ID for this model page is x-ai/grok-4.3. Gate.AI documentation states that developers can use OpenAI-compatible clients by replacing the base URL and API key, and it identifies /chat/completions as the chat-completions endpoint path.

Python Example

from openai import OpenAI
import os
client = OpenAI(
    api_key=os.environ["GATEAI_API_KEY"],
    base_url="https://api.gate.ai/openai/v1",
)
response = client.chat.completions.create(
    model="x-ai/grok-4.3",
    messages=[
        {
            "role": "user",
            "content": "Summarize three deployment risks for a long-context AI assistant."
        }
    ],
)
print(response.choices[0].message.content)

curl Example

curl https://api.gate.ai/openai/v1/chat/completions \
  -H "Authorization: Bearer $GATEAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "x-ai/grok-4.3",
    "messages": [
      {
        "role": "user",
        "content": "Summarize three deployment risks for a long-context AI assistant."
      }
    ]
  }'

Through Gate.AI, developers can use an OpenAI-compatible integration pattern while selecting the Gate.AI listing ID for Grok 4.3. Before production rollout, teams should verify current model availability, account permissions, billing configuration, and rate behavior inside their Gate.AI workspace.

FAQs

What is Grok 4.3’s context window?
Grok 4.3 has a documented 1,000,000-token context window as of July 2026. This makes it relevant for long-document analysis, extended conversations, and retrieval-augmented workflows.

How much does Grok 4.3 cost?
xAI documents \$1.25 per 1M input tokens, \$0.20 per 1M cached input tokens, and \$2.50 per 1M output tokens. Gate.AI listing details for this page show higher rates above 200K context.

How can developers access Grok 4.3?
Developers can access Grok 4.3 through xAI’s API using grok-4.3. This article also documents Gate.AI access using the listing ID x-ai/grok-4.3 with Gate.AI’s OpenAI-compatible API base URL.

What is Grok 4.3 useful for?
Grok 4.3 may fit long-context analysis, agentic tool workflows, structured extraction, multimodal image understanding, and research assistance. It should not be used for high-stakes decisions without expert review.