Grok 4.3

• 🏢 xAI's flagship Grok reasoning model, released April 2026.
• 📏 1M-token context window for long documents and codebases.
• 👁️ Accepts text and image input, produces text output.
• 🔧 Function calling, structured outputs, and prompt caching supported.
• 🌐 Built-in web search for current-events grounding.
• 🧠 Configurable reasoning effort from none to high.
• 🎯 Positioned for agentic tool use and instruction following.
• 🆕 Successor to Grok 4.20 in xAI's lineup.

xAI

xAI is an American artificial intelligence company and wholly owned subsidiary of SpaceX. The company develops AI systems under the Grok brand, spanning language models, image generation, and video synthesis. xAI has quickly established itself as a multimodal…

Grok 4.3 is xAI's current Grok flagship for text and image-input workflows, a reasoning model with function calling, structured outputs, prompt caching, and built-in web search. It targets agentic workflows, instruction following, and accuracy-critical tasks such as advanced logic, math, and multi-step investigations. The xAI API exposes the model through a latest alias and offers configurable reasoning effort spanning none, low, medium, and high.

Within xAI's lineup, Grok 4.3 succeeds its same-family predecessor Grok 4.20. Like prior Grok 4-series releases, it pairs a large context window with built-in retrieval for grounding on recent information.

The 1M-token window supports long documents, extended chat histories, and multi-file codebases in a single pass. Parallel function calling lets the model request multiple tool calls in one response, which suits orchestration and automation use cases.

Beyond this text model, xAI's broader Grok family includes related siblings such as the agentic Grok 4.20 Multi-Agent and the coding-focused Grok Build 0.1, alongside the Grok Imagine image and video generators. Grok 4.3 is the text-and-vision reasoning entry point in that ecosystem, accessed through xAI's API with OpenAI-SDK-compatible interfaces.