Grok Chat Completions (All Models, Full Parameters)

curl --request POST \
  --url https://direct.evolink.ai/v1/chat/completions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "grok-4.5",
  "messages": [
    {
      "role": "system",
      "content": "You are a concise assistant."
    },
    {
      "role": "user",
      "content": "Explain prompt caching in one sentence."
    }
  ],
  "stream": false,
  "max_tokens": 1024,
  "temperature": 0.7,
  "top_p": 0.95,
  "tools": [
    {
      "type": "function",
      "function": {}
    }
  ]
}
'

import requests

url = "https://direct.evolink.ai/v1/chat/completions"

payload = {
    "model": "grok-4.5",
    "messages": [
        {
            "role": "system",
            "content": "You are a concise assistant."
        },
        {
            "role": "user",
            "content": "Explain prompt caching in one sentence."
        }
    ],
    "stream": False,
    "max_tokens": 1024,
    "temperature": 0.7,
    "top_p": 0.95,
    "tools": [
        {
            "type": "function",
            "function": {}
        }
    ]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'grok-4.5',
    messages: [
      {role: 'system', content: 'You are a concise assistant.'},
      {role: 'user', content: 'Explain prompt caching in one sentence.'}
    ],
    stream: false,
    max_tokens: 1024,
    temperature: 0.7,
    top_p: 0.95,
    tools: [{type: 'function', function: {}}]
  })
};

fetch('https://direct.evolink.ai/v1/chat/completions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://direct.evolink.ai/v1/chat/completions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'grok-4.5',
    'messages' => [
        [
                'role' => 'system',
                'content' => 'You are a concise assistant.'
        ],
        [
                'role' => 'user',
                'content' => 'Explain prompt caching in one sentence.'
        ]
    ],
    'stream' => false,
    'max_tokens' => 1024,
    'temperature' => 0.7,
    'top_p' => 0.95,
    'tools' => [
        [
                'type' => 'function',
                'function' => [
                                
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://direct.evolink.ai/v1/chat/completions"

	payload := strings.NewReader("{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://direct.evolink.ai/v1/chat/completions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://direct.evolink.ai/v1/chat/completions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "chatcmpl-20260812164515123456789AbCdEfGh",
  "model": "grok-4.5",
  "object": "chat.completion",
  "created": 1786538000,
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Prompt caching reuses previously processed prompt prefixes so repeated context is billed at a lower rate.",
        "tool_calls": [
          {}
        ]
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 504,
    "completion_tokens": 2,
    "total_tokens": 526,
    "prompt_tokens_details": {
      "cached_tokens": 0
    }
  }
}

{
  "error": {
    "code": 400,
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": 401,
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": 402,
    "message": "Insufficient quota",
    "type": "insufficient_quota_error",
    "fallback_suggestion": "https://evolink.ai/dashboard/billing"
  }
}

{
  "error": {
    "code": 429,
    "message": "Rate limit exceeded",
    "type": "rate_limit_error",
    "fallback_suggestion": "retry after 60 seconds"
  }
}

{
  "error": {
    "code": 500,
    "message": "Internal server error",
    "type": "internal_server_error",
    "fallback_suggestion": "try again later"
  }
}

{
  "error": {
    "code": 503,
    "message": "Service temporarily unavailable",
    "type": "service_unavailable_error",
    "fallback_suggestion": "retry after 30 seconds"
  }
}

Chat Completions API

Grok All-Model API - Chat Completions Reference

OpenAI-compatible Chat Completions endpoint for xAI Grok text models; pick the model via the model parameter (see the table on the model parameter for all values)
grok-4.5: 500K-token context window; prompts of 200K tokens or more are billed at 2x for all token types
Prompt caching is automatic: cached prompt tokens are billed at the lower cached-input rate
Synchronous and streaming (SSE) modes
Regular function tool calling is supported; xAI server-side tools are available on the Responses API only

POST

chat

completions

Grok Chat Completions (All Models, Full Parameters)

curl --request POST \
  --url https://direct.evolink.ai/v1/chat/completions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "grok-4.5",
  "messages": [
    {
      "role": "system",
      "content": "You are a concise assistant."
    },
    {
      "role": "user",
      "content": "Explain prompt caching in one sentence."
    }
  ],
  "stream": false,
  "max_tokens": 1024,
  "temperature": 0.7,
  "top_p": 0.95,
  "tools": [
    {
      "type": "function",
      "function": {}
    }
  ]
}
'

import requests

url = "https://direct.evolink.ai/v1/chat/completions"

payload = {
    "model": "grok-4.5",
    "messages": [
        {
            "role": "system",
            "content": "You are a concise assistant."
        },
        {
            "role": "user",
            "content": "Explain prompt caching in one sentence."
        }
    ],
    "stream": False,
    "max_tokens": 1024,
    "temperature": 0.7,
    "top_p": 0.95,
    "tools": [
        {
            "type": "function",
            "function": {}
        }
    ]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'grok-4.5',
    messages: [
      {role: 'system', content: 'You are a concise assistant.'},
      {role: 'user', content: 'Explain prompt caching in one sentence.'}
    ],
    stream: false,
    max_tokens: 1024,
    temperature: 0.7,
    top_p: 0.95,
    tools: [{type: 'function', function: {}}]
  })
};

fetch('https://direct.evolink.ai/v1/chat/completions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://direct.evolink.ai/v1/chat/completions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'grok-4.5',
    'messages' => [
        [
                'role' => 'system',
                'content' => 'You are a concise assistant.'
        ],
        [
                'role' => 'user',
                'content' => 'Explain prompt caching in one sentence.'
        ]
    ],
    'stream' => false,
    'max_tokens' => 1024,
    'temperature' => 0.7,
    'top_p' => 0.95,
    'tools' => [
        [
                'type' => 'function',
                'function' => [
                                
                ]
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://direct.evolink.ai/v1/chat/completions"

	payload := strings.NewReader("{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://direct.evolink.ai/v1/chat/completions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://direct.evolink.ai/v1/chat/completions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"grok-4.5\",\n  \"messages\": [\n    {\n      \"role\": \"system\",\n      \"content\": \"You are a concise assistant.\"\n    },\n    {\n      \"role\": \"user\",\n      \"content\": \"Explain prompt caching in one sentence.\"\n    }\n  ],\n  \"stream\": false,\n  \"max_tokens\": 1024,\n  \"temperature\": 0.7,\n  \"top_p\": 0.95,\n  \"tools\": [\n    {\n      \"type\": \"function\",\n      \"function\": {}\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "chatcmpl-20260812164515123456789AbCdEfGh",
  "model": "grok-4.5",
  "object": "chat.completion",
  "created": 1786538000,
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Prompt caching reuses previously processed prompt prefixes so repeated context is billed at a lower rate.",
        "tool_calls": [
          {}
        ]
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 504,
    "completion_tokens": 2,
    "total_tokens": 526,
    "prompt_tokens_details": {
      "cached_tokens": 0
    }
  }
}

{
  "error": {
    "code": 400,
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": 401,
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": 402,
    "message": "Insufficient quota",
    "type": "insufficient_quota_error",
    "fallback_suggestion": "https://evolink.ai/dashboard/billing"
  }
}

{
  "error": {
    "code": 429,
    "message": "Rate limit exceeded",
    "type": "rate_limit_error",
    "fallback_suggestion": "retry after 60 seconds"
  }
}

{
  "error": {
    "code": 500,
    "message": "Internal server error",
    "type": "internal_server_error",
    "fallback_suggestion": "try again later"
  }
}

{
  "error": {
    "code": 503,
    "message": "Service temporarily unavailable",
    "type": "service_unavailable_error",
    "fallback_suggestion": "retry after 30 seconds"
  }
}

BaseURL: The default BaseURL is https://direct.evolink.ai, which has better support for text models and long-lived connections. https://api.evolink.ai is the primary endpoint for multimodal services and serves as a fallback address for text models.

Server-side tools (web search, X search, code execution, attachment search, collections search) are only available on the Responses API. The Chat Completions endpoint supports regular function tool calling only.

Authorizations

Authorization

string

header

required

##All APIs require Bearer Token authentication##

Get API Key:

Visit API Key Management Page to get your API Key

Add to request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

required

Model to call:

Model ID	Positioning
`grok-4.5`	xAI reasoning + tool-use model, 500K context window

Available options:

grok-4.5

Example:

"grok-4.5"

messages

object[]

required

List of chat messages. Supports system, user, and assistant roles.

Minimum array length: 1

Show child attributes

Example:

[
  {
    "role": "system",
    "content": "You are a concise assistant."
  },
  {
    "role": "user",
    "content": "Explain prompt caching in one sentence."
  }
]

stream

boolean

default:false

Whether to return a streaming response (SSE, chat.completion.chunk events). Default false.

Example:

false

max_tokens

integer

Maximum number of tokens to generate. Passed through to the model as-is.

Example:

1024

temperature

number

Sampling temperature (0-2). Higher values produce more random output.

Example:

0.7

top_p

number

Nucleus sampling parameter (0-1).

Example:

0.95

tools

object[]

Regular OpenAI function tool definitions (client-side function calling, no extra per-call fee). xAI server-side tools are only available on the Responses API.

Show child attributes

tool_choice

Controls function selection: "auto" / "none" / "required", or an object pinning a specific function.

Available options:

auto,

none,

required

Response

Chat completion generated successfully (JSON object, or an SSE stream of chat.completion.chunk events when stream=true)

string

Unique identifier for the chat completion

Example:

"chatcmpl-20260812164515123456789AbCdEfGh"

model

string

Model name actually used

Example:

"grok-4.5"

object

enum<string>

Response type

Available options:

chat.completion

Example:

"chat.completion"

created

integer

Creation timestamp

Example:

1786538000

choices

object[]

List of chat completion choices

Show child attributes

usage

object

Token usage statistics. Prompts of 200K tokens or more are billed at 2x for all token types (input, cached input, output).

Show child attributes

Image Series

Video Series

Audio Series

Text Series

Account Management

Task Management

File Management

Grok All-Model API - Chat Completions Reference

Authorizations

Body

Response