CometAPI

LiteLLM supports all AI models from CometAPI. CometAPI provides access to 500+ AI models through a unified API interface, including cutting-edge models like GPT-5, Claude Opus 4.1, and various other state-of-the-art language models.

Authentication

To use CometAPI models, you need to obtain an API key from CometAPI Token Console. CometAPI offers free tokens for new users - you can get your free API key instantly by registering.

Usage

Set your CometAPI key as an environment variable and use the completion function:

import os
from litellm import completion

# Set API key
os.environ["COMETAPI_KEY"] = "your_comet_api_key_here"

# Define messages
messages = [{"content": "Hello, how are you?", "role": "user"}]

# Method 1: Using environment variable (recommended)
response = completion(
    model="cometapi/gpt-5", 
    messages=messages
)

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

Alternative Usage - Explicit API Key

You can also pass the API key explicitly:

import os
from litellm import completion

# Define messages
messages = [{"content": "Hello, how are you?", "role": "user"}]

# Method 2: Explicitly passing API key
response = completion(
    model="cometapi/gpt-4o", 
    messages=messages, 
    api_key="your_comet_api_key_here"
)

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

Usage - Streaming

Just set stream=True when calling completion:

import os
from litellm import completion

os.environ["COMETAPI_KEY"] = "your_comet_api_key_here"

messages = [{"content": "Hello, how are you?", "role": "user"}]

response = completion(
    model="cometapi/gpt-5",
    messages=messages,
    stream=True
)

for chunk in response:
    print(chunk.choices[0].delta.content or "", end="")

Usage - Async Streaming

For async streaming, use acompletion:

from litellm import acompletion
import asyncio, os, traceback

async def completion_call():
    try:
        os.environ["COMETAPI_KEY"] = "your_comet_api_key_here"
        
        print("test acompletion + streaming")
        response = await acompletion(
            model="cometapi/chatgpt-4o-latest", 
            messages=[{"content": "Hello, how are you?", "role": "user"}], 
            stream=True
        )
        print(f"response: {response}")
        async for chunk in response:
            print(chunk)
    except:
        print(f"error occurred: {traceback.format_exc()}")
        pass

# Run the async function
await completion_call()

CometAPI Models

CometAPI offers access to 500+ AI models through a unified API. Some popular models include:

Model Name	Function Call
cometapi/gpt-5	completion('cometapi/gpt-5', messages)
cometapi/gpt-5-mini	completion('cometapi/gpt-5-mini', messages)
cometapi/gpt-5-nano	completion('cometapi/gpt-5-nano', messages)
cometapi/gpt-oss-20b	completion('cometapi/gpt-oss-20b', messages)
cometapi/gpt-oss-120b	completion('cometapi/gpt-oss-120b', messages)
cometapi/chatgpt-4o-latest	completion('cometapi/chatgpt-4o-latest', messages)

For a complete list of available models, visit the CometAPI Models page.

Environment Variables

Variable	Description	Required
COMETAPI_KEY	Your CometAPI API key	Yes

Error Handling

import os
from litellm import completion

try:
    os.environ["COMETAPI_KEY"] = "your_comet_api_key_here"
    
    messages = [{"content": "Hello, how are you?", "role": "user"}]
    
    response = completion(
        model="cometapi/gpt-5",
        messages=messages
    )
    
    print(response.choices[0].message.content)
    
except Exception as e:
    print(f"Error: {e}")