xAIMediumUltra

Grok 4.5

xAI's coding-focused Grok model with a 500K-token context window - same token rates as Grok 4.6 with cheaper cache reads.

3,716/11,148credits

input / output · per 1M tokens

Optimized for coding workloads

500K context window

OpenAI-compatible API (chat completions)

Prompt caching with discounted cache reads

Long-context tier: prompts reaching 200K tokens bill the whole request at 2x rates

Run it right now

Test this model instantly in the Console Playground — no code required

Use with AI Assistant

Copy usage instructions for Claude, ChatGPT, or other AI

llms.txtllms.txt ↗

Model Specifications

Context Window

500K

tokens

Max Output

33K

tokens

Training Cutoff

2025-11

Compatible SDK

OpenAI

Capabilities

Vision

Function Calling

Streaming

JSON Mode

System Prompt

Token Pricing (per 1M tokens)

Token Type	Credits	USD Equivalent
Input Tokens	3,716	$2.48
Output Tokens	11,148	$7.43
Cached Tokens	557.4	$0.37

* 1,500 credits ≈ $1 (actual charges may vary based on usage)

Quick Start

curl -X POST "https://api.core.today/llm/grok/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cdt_your_api_key" \
  -d '{
  "model": "grok-4.5",
  "messages": [
    {
      "role": "user",
      "content": "Summarize the attached report in 5 bullets."
    }
  ],
  "max_tokens": 1024
}'

Parameters

Parameter	Type	Required	Default	Description
`model`	string	Yes	-	Model ID, e.g. "grok-4.5".
`messages`	array	Yes	-	Chat messages in OpenAI format (system/user/assistant roles).
`temperature`	number	No	0.7	Sampling temperature (0-2).
`max_tokens`	integer	No	2048	Maximum completion tokens.
`stream`	boolean	No	false	Stream the response as server-sent events.

Examples

Chat completion

OpenAI-compatible chat completion request

curl -X POST "https://api.core.today/llm/grok/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cdt_your_api_key" \
  -d '{
  "model": "grok-4.5",
  "messages": [
    {
      "role": "user",
      "content": "Summarize the attached report in 5 bullets."
    }
  ],
  "max_tokens": 1024
}'