Overview
Grok 4.3 is a model from xAI that the vendor describes as fast and reliable, with strong tool calling and instruction following. It supports reasoning that can be adjusted or switched off, structured output and image input, and it handles very long prompts thanks to a 1M-token context window.
It has a 1M-token context window. It accepts text and image input and returns text. It was released on April 30, 2026.
Capabilities
Tool calling and instruction following are the headline strengths: Grok 4.3 can pick the right function for a request, fill in its arguments, and keep to the formatting and constraints written in a prompt. Structured output makes the results easy to parse.
Reasoning is configurable, so you can let the model think before answering or turn thinking off for simple requests. Images can be sent with text, and replies are text.
Pricing
Grok 4.3 is priced from $1.25 per 1M input tokens and $2.50 per 1M output tokens. Cached input reads cost $0.20 per 1M tokens. The prices shown are for the starting tier; requests with very long prompts are billed at higher rates.
Grok 4.3 is available through RealRelay's OpenAI-compatible API.
Use cases
Use Grok 4.3 for tool-driven assistants and automations that must follow detailed instructions exactly, such as support agents that look up records, call internal APIs and answer in a set format.
Its 1M-token context window also suits reading long contracts, logs or transcripts in one request, with screenshots attached when the question needs them.
What is Grok 4.3?
Grok 4.3 is a model from xAI that the vendor describes as fast and reliable, with strong tool calling and instruction following. It supports reasoning that can be adjusted or switched off, structured output and image input, and it handles very long prompts thanks to a 1M-token context window.
How much does Grok 4.3 cost?
Grok 4.3 is priced from $1.25 per 1M input tokens and $2.50 per 1M output tokens. Cached input reads cost $0.20 per 1M tokens. The prices shown are for the starting tier; requests with very long prompts are billed at higher rates.
What is the context window of Grok 4.3?
Grok 4.3 has a 1M-token context window.
What inputs and outputs does Grok 4.3 support?
Grok 4.3 accepts text and image input and returns text.
Does Grok 4.3 support tool calling and reasoning?
Yes. Grok 4.3 supports tool calling, structured output and reasoning that can be adjusted or switched off, and it accepts image input.
When was Grok 4.3 released?
Grok 4.3 was released on April 30, 2026.
How do I call Grok 4.3 through the API?
Call Grok 4.3 through RealRelay's OpenAI-compatible API by setting the model field to xai/grok-4.3.