Grok API Endpoints: Comprehensive Access to Language, Vision, and Tooling


Grok API Endpoints

Overview

The Grok API by xAI offers a powerful suite of RESTful endpoints for building advanced AI applications. Designed for compatibility with OpenAI and Anthropic formats, the Grok API supports chat, completion, function calling, embeddings, vision processing, and image generation—all with a massive token context window and real-time reasoning capabilities.

Whether you're creating chatbots, coding assistants, or multimodal search tools, understanding the Grok API endpoints is crucial for effective implementation.

Core REST API Endpoints

These endpoints form the foundation of Grok 4’s integration capabilities:

Endpoint Method Description
/v1/chat/completions POST Generates structured, chat-style responses with support for text, reasoning, and function calling
/v1/completions POST Generates standard text completions (non-chat)
/v1/models GET Lists all available Grok models
/v1/models/{model_id} GET Fetches detailed information about a specific model
/v1/embeddings POST Generates text embeddings for search, similarity, and retrieval tasks
/v1/images/generate POST Generates images from natural language prompts
/v1/vision/analyze POST Analyzes image content using vision models
/v1/tokenize POST Tokenizes input text for usage estimation
/v1/health GET Checks the health/status of the API service

Base URL: https://api.x.ai/v1/

Third-Party & Proxy Endpoints

For flexibility and ecosystem integration, Grok 4 is also accessible through popular API proxy platforms:

OpenRouter

  • Endpoint: https://openrouter.ai/api/v1/chat/completions

  • Model ID: "x-ai/grok-4"

CometAPI

  • Endpoint: https://api.cometapi.com/v1/chat/completions

  • Model ID: "grok-4"

Cloudflare AI Gateway

  • Endpoint: https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/grok

  • Enables enterprise-grade deployments through Cloudflare edge infrastructure.



Key Features Supported by Endpoints

Capability Description
Chat Completions Interactive AI conversations, memory, coding, and advanced logic
Function Calling Call external APIs, perform real-time tool use, automate workflows
Vision & Image Image understanding and generation (in rollout stages)
Structured Outputs Return results in machine-readable formats like JSON or tables
Embeddings Create vector representations for semantic search or recommendation engines
Tokenization Analyze token count to optimize cost and prevent request failures
Model Discovery Fetch supported models and their capabilities dynamically

Example: Chat Completion Request

Here’s how to use the most common endpoint:

json
POST https://api.x.ai/v1/chat/completions Headers: Authorization: Bearer YOUR_API_KEY Content-Type: application/json Body: { "model": "grok-4", "messages": [ {"role": "user", "content": "Summarize the key features of Grok 4."} ], "max_tokens": 200 }

Replace:

  • YOUR_API_KEY with your valid API key

  • model with your selected Grok model

Notes and Best Practices

  • Authentication: All endpoints require a Bearer token in the Authorization header.

  • Compatibility: Grok API is structured similarly to OpenAI and Anthropic APIs, making migration easy.

  • Rollout: Some capabilities (e.g., vision, image generation) may be in limited release or preview.

  • Rate Limits: Vary based on subscription tier—check your xAI dashboard or provider.



Summary Table

Category Key Endpoint(s)
Chat & Completion /v1/chat/completions, /v1/completions
Model Management /v1/models, /v1/models/{model_id}
Embeddings /v1/embeddings
Vision/Image /v1/images/generate, /v1/vision/analyze
Token Management /v1/tokenize
Third-Party Proxies OpenRouter, CometAPI, Cloudflare Gateway

FAQ's

1. What are the main Grok API endpoints for text and image processing tasks?

The Grok API provides a set of specialized endpoints for handling both text and image data:

Text Processing Endpoints:

  • /v1/chat/completions: Primary endpoint for chat-based reasoning, dialogue, and agent tasks.

  • /v1/completions: Used for traditional (non-chat) language generation.

  • /v1/embeddings: Converts text into vector embeddings for search and semantic analysis.

  • /v1/tokenize: Analyzes token usage for input optimization.

Image Processing Endpoints:

  • /v1/images/generate: Creates images based on text prompts (image generation).

  • /v1/vision/analyze: Interprets and analyzes uploaded images (vision model).

These endpoints enable both multimodal AI tasks and standard NLP workflows, making Grok 4 a versatile tool for developers.

2. How can I use Grok's API to perform reasoning and structured outputs?

Grok 4 supports advanced reasoning and structured output formatting through the /v1/chat/completions endpoint.

  • To enable reasoning: Provide multi-turn messages with complex prompts. Grok can remember context and solve problems step-by-step.

  • To request structured outputs: Format your prompt to specify the desired structure (e.g., “Return this in JSON format”). Grok will respond in a predictable machine-readable format.

Example Prompt:

json
"Please analyze the following product reviews and return a JSON with sentiment scores, keywords, and summary."

This capability is ideal for:

3. What steps are involved in making chat or image requests with the Grok API?

To make a chat or image request using the Grok API:

Step 1: Authentication

Include your API key in the Authorization header:

http
Authorization: Bearer YOUR_API_KEY

Step 2: Select Endpoint

  • For chat: https://api.x.ai/v1/chat/completions

  • For image generation: https://api.x.ai/v1/images/generate

Step 3: Create Payload

Example chat payload:

json
{ "model": "grok-4", "messages": [ { "role": "user", "content": "Explain quantum computing in simple terms." } ], "max_tokens": 200 }

Example image payload:

json
{ "prompt": "A futuristic city skyline at sunset", "model": "grok-image" }

Step 4: Send Request

Use tools like curl, Python requests, or JavaScript fetch to send the POST request with headers and body.

4. How does Grok's tool calling feature integrate third-party functions via API endpoints?

Grok 4's function calling feature lets you define external tools (e.g., APIs, code functions) and invoke them directly within the chat completion flow.

How It Works:

  • You include a list of callable functions (with parameters and schema) in the request.

  • Grok decides when to call them based on user input.

  • Once the function is invoked, your backend handles the request and returns a response to continue the chat.

Example use cases:

  • Real-time data fetching (weather, stock prices)

  • Database querying

  • Code execution or translation

  • Task automation (e.g., email, calendar, webhooks)

This feature makes Grok 4 agent-ready, bridging natural language and executable APIs.

5. What are the key differences between Grok 4 and earlier versions in terms of available endpoints?

Here’s how Grok 4 improves over Grok 3 and 3-mini in terms of endpoints:

Feature Grok 3 / 3-mini Grok 4
Chat Completions ✅ ✅ (Improved reasoning)
Image Generation ❌ ✅ (Rolling out)
Vision Analysis ❌ ✅ (Rolling out)
Function Calling ❌ (Limited or none) ✅ Native tool use
Structured Output ✅ (basic) ✅ (JSON, tables, schema aware)
3rd-Party Integration Basic OpenRouter Full support (Cloudflare, CometAPI, etc.)
Context Window 131,072 tokens 256,000 tokens

Grok 4 dramatically expands the breadth and depth of available endpoints, especially for multimodal tasks and agentic automation.

Conclusion

The Grok API endpoints provide a robust, flexible, and scalable interface for developers building cutting-edge AI applications. From natural language reasoning to image analysis and multimodal AI, Grok 4 supports a wide range of use cases with familiar API patterns and high context capacity.