Overview
Grok 4.20 (0309 Reasoning) is the reasoning variant of xAI's Grok 4.20, a high-performance model built for agentic tool calling and strict prompt adherence. xAI says it aims for precise and truthful responses. It supports reasoning, tool calling and structured output, accepts text and image input, and offers a 1M-token context window.
It has a 1M-token context window. It accepts text and image input and returns text.
Capabilities
This variant thinks before it responds, which helps with multi-step tasks. It pairs reasoning with tool calling and structured output, so an agent can decide which tool to use, call it, and return data in the format a downstream system needs.
Prompts can include images next to text, and a large context window keeps long instructions, documents and tool results in view. Output is text.
Pricing
Grok 4.20 (0309 Reasoning) 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 4.20 (0309 Reasoning) is available through RealRelay's OpenAI-compatible API.
Use cases
Use Grok 4.20 (0309 Reasoning) for agents that must follow a detailed prompt step by step, such as workflows that look up data with tools, reason about the results and return a structured answer.
Because it accepts images and a 1M-token context, it also works for questions over long reports or screenshots where the answer needs to stay faithful to the source.
What is Grok 4.20 (0309 Reasoning)?
Grok 4.20 (0309 Reasoning) is the reasoning variant of xAI's Grok 4.20, a high-performance model built for agentic tool calling and strict prompt adherence. xAI says it aims for precise and truthful responses. It supports reasoning, tool calling and structured output, accepts text and image input, and offers a 1M-token context window.
How much does Grok 4.20 (0309 Reasoning) cost?
Grok 4.20 (0309 Reasoning) 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 4.20 (0309 Reasoning)?
Grok 4.20 (0309 Reasoning) has a 1M-token context window.
What inputs and outputs does Grok 4.20 (0309 Reasoning) support?
Grok 4.20 (0309 Reasoning) accepts text and image input and returns text.
Does Grok 4.20 (0309 Reasoning) support tool calling?
Yes. Grok 4.20 (0309 Reasoning) supports tool calling, structured output and reasoning, and it accepts text and image input.
What is Grok 4.20 (0309 Reasoning) used for?
Use Grok 4.20 (0309 Reasoning) for agents that must follow a detailed prompt step by step, such as workflows that look up data with tools, reason about the results and return a structured answer.
How do I call Grok 4.20 (0309 Reasoning) through the API?
Call Grok 4.20 (0309 Reasoning) through RealRelay's OpenAI-compatible API by setting the model field to xai/grok-4.20-0309-reasoning.