How to Use Grok 3 & Grok 3 Mini API for Free (2026)

How to Use Grok 3 & Grok 3 Mini API for Free in 2026

xAI's Grok 3 and Grok 3 Mini are among the most capable language models available, excelling at reasoning, coding, math, and general conversation. The best part: xAI offers a generous free API tier that lets developers build and test applications without spending anything.

This guide covers how to get free API access, the rate limits and capabilities of each model, code examples in Python and JavaScript, and how Grok 3 compares to GPT-4o, Claude, and Gemini.

Grok 3 Model Overview

xAI offers several Grok 3 variants through their API:

Model	Context Window	Strengths	Best For
Grok 3	131,072 tokens	Top-tier reasoning, coding, analysis	Complex tasks requiring deep thinking
Grok 3 Mini	131,072 tokens	Fast, efficient, strong reasoning	High-volume tasks, quick responses
Grok 3 Mini (Fast)	131,072 tokens	Lowest latency	Real-time applications

All models support function calling, structured output (JSON mode), system prompts, and streaming.

Step 1: Get Your Free API Key

1. Go to console.x.ai.
2. Sign up with your X (Twitter) account or email.
3. Navigate to API Keys and click Create API Key.
4. Copy your key (starts with xai-).
5. New accounts receive $25 in free API credits per month.

Free Tier Limits

Limit	Grok 3	Grok 3 Mini
Free credits	$25/month	$25/month
Rate limit (RPM)	30 requests/min	60 requests/min
Rate limit (TPM)	100K tokens/min	200K tokens/min
Max output tokens	16,384	16,384
Context window	131,072	131,072

The $25 monthly credit is generous. At Grok 3 Mini's pricing of $0.30/M input tokens and $0.50/M output tokens, that translates to millions of tokens per month for free.

Step 2: Make Your First API Call

Grok 3's API follows the OpenAI-compatible format, making it easy to integrate with existing code.

Python Example

import openai

client = openai.OpenAI(
    api_key="xai-your-api-key-here",
    base_url="https://api.x.ai/v1"
)

# Basic chat completion
response = client.chat.completions.create(
    model="grok-3-mini",
    messages=[
        {
            "role": "system",
            "content": "You are a helpful coding assistant. Be concise and provide working code."
        },
        {
            "role": "user",
            "content": "Write a Python function that implements binary search on a sorted list."
        }
    ],
    temperature=0.7,
    max_tokens=2048
)

print(response.choices[0].message.content)

JavaScript/Node.js Example

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "xai-your-api-key-here",
  baseURL: "https://api.x.ai/v1",
});

const response = await client.chat.completions.create({
  model: "grok-3-mini",
  messages: [
    {
      role: "system",
      content: "You are a helpful coding assistant.",
    },
    {
      role: "user",
      content: "Write a TypeScript function to debounce API calls.",
    },
  ],
  temperature: 0.7,
  max_tokens: 2048,
});

console.log(response.choices[0].message.content);

cURL Example

curl https://api.x.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer xai-your-api-key-here" \
  -d '{
    "model": "grok-3-mini",
    "messages": [
      {"role": "user", "content": "Explain async/await in JavaScript in 3 sentences."}
    ],
    "temperature": 0.7
  }'

Step 3: Use Streaming for Real-Time Responses

For chat applications and interactive tools, streaming provides a better user experience:

import openai

client = openai.OpenAI(
    api_key="xai-your-api-key-here",
    base_url="https://api.x.ai/v1"
)

stream = client.chat.completions.create(
    model="grok-3-mini",
    messages=[
        {"role": "user", "content": "Explain how DNS resolution works step by step."}
    ],
    stream=True
)

for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)

Step 4: Use Function Calling

Grok 3 supports function calling for building AI agents and tool-using applications:

import openai
import json

client = openai.OpenAI(
    api_key="xai-your-api-key-here",
    base_url="https://api.x.ai/v1"
)

tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Get the current weather for a location",
            "parameters": {
                "type": "object",
                "properties": {
                    "location": {
                        "type": "string",
                        "description": "City name, e.g., San Francisco"
                    },
                    "unit": {
                        "type": "string",
                        "enum": ["celsius", "fahrenheit"],
                        "description": "Temperature unit"
                    }
                },
                "required": ["location"]
            }
        }
    }
]

response = client.chat.completions.create(
    model="grok-3",
    messages=[
        {"role": "user", "content": "What's the weather like in Tokyo?"}
    ],
    tools=tools,
    tool_choice="auto"
)

# Handle the tool call
message = response.choices[0].message
if message.tool_calls:
    tool_call = message.tool_calls[0]
    function_args = json.loads(tool_call.function.arguments)
    print(f"Function: {tool_call.function.name}")
    print(f"Arguments: {function_args}")

Step 5: Use JSON Mode for Structured Output

Force Grok 3 to return valid JSON for reliable parsing:

response = client.chat.completions.create(
    model="grok-3-mini",
    messages=[
        {
            "role": "system",
            "content": "You are a data extraction assistant. Always respond with valid JSON."
        },
        {
            "role": "user",
            "content": "Extract the key information from this text: 'Apple Inc. reported Q4 2025 revenue of $95.4 billion, up 8% year-over-year. Net income was $24.1 billion.'"
        }
    ],
    response_format={"type": "json_object"},
    temperature=0
)

import json
data = json.loads(response.choices[0].message.content)
print(json.dumps(data, indent=2))

Grok 3 Pricing Breakdown

When your free credits run out, here is what the paid pricing looks like:

Model	Input (per 1M tokens)	Output (per 1M tokens)
Grok 3	$3.00	$15.00
Grok 3 Mini	$0.30	$0.50
Grok 3 Mini (Fast)	$0.10	$0.25

Grok 3 Mini offers exceptional value -- at $0.30/M input tokens, it is one of the cheapest high-quality models available.

Grok 3 vs. Competitors

Feature	Grok 3	GPT-4o	Claude Sonnet	Gemini 2.5 Pro
Free API credits	$25/mo	$5 initial	$5 initial	$0 (AI Studio free)
Input price (per 1M)	$3.00	$2.50	$3.00	$1.25
Output price (per 1M)	$15.00	$10.00	$15.00	$10.00
Context window	131K	128K	200K	1M
Coding	Excellent	Excellent	Excellent	Excellent
Reasoning	Excellent	Excellent	Excellent	Excellent
Speed	Fast	Fast	Fast	Medium
OpenAI-compatible API	Yes	Yes (native)	No (different format)	No (different format)

When to Choose Grok 3

• Best free tier: $25/month in free credits beats most competitors
• OpenAI compatibility: Drop-in replacement in existing OpenAI SDK code
• Grok 3 Mini value: Among the cheapest high-quality models for production use
• Reasoning tasks: Grok 3 excels at math, logic, and complex analysis

When to Choose Alternatives

• Longest context: Gemini 2.5 Pro offers 1M tokens
• Anthropic ecosystem: Claude integrates with MCP, Claude Code, and Artifacts
• Widest ecosystem: GPT-4o has the most third-party integrations

Tips for Maximizing Free Credits

1. Use Grok 3 Mini for most tasks. It is 10x cheaper than Grok 3 and performs well for the majority of use cases. Reserve Grok 3 for tasks that specifically need deeper reasoning.

2. Set max_tokens appropriately. Do not default to the maximum. If you expect a 200-token response, set max_tokens: 500 to avoid wasted output tokens.

3. Cache repeated prompts. If you send the same system prompt frequently, xAI may offer prompt caching discounts (check the latest docs).

4. Use temperature 0 for deterministic tasks. For code generation and data extraction, lower temperatures reduce unnecessary token usage from verbose responses.

5. Monitor usage in the dashboard. Track your credit consumption at console.x.ai to avoid unexpected charges.

Frequently Asked Questions

Is the Grok 3 API really free? Yes, you get $25 in free credits every month. This resets monthly and covers millions of tokens with Grok 3 Mini.

Do I need a paid X (Twitter) account? No. You can sign up for the xAI API with just an email address.

Can I use Grok 3 with the OpenAI Python library? Yes. Just change the base_url to https://api.x.ai/v1 and use your xAI API key. All other code stays the same.

What happens when free credits run out? API calls will return an error. You can add a payment method for pay-as-you-go usage or wait for the monthly reset.

Does Grok 3 have content restrictions? Grok 3 has fewer content restrictions than some competitors, but it still has safety guidelines. It is generally more permissive for creative and research use cases.

Wrapping Up

Grok 3 and Grok 3 Mini offer one of the best free API tiers in the AI space. The $25 monthly credit, combined with Grok 3 Mini's low pricing, gives developers millions of free tokens to build with. The OpenAI-compatible API format makes it trivial to integrate into existing projects.

If you are building applications that need AI-generated media like images, video, or talking avatars, try Hypereal AI free -- 35 credits, no credit card required. Pair Grok 3 for the intelligence layer with Hypereal for visual content generation.