OpenRouter Quickstart Guide

OpenRouter provides a unified API that gives you access to hundreds of AI models through a single endpoint, while automatically handling fallbacks and selecting the most cost-effective options. Get started with just a few lines of code using your preferred SDK or framework.

Want to chat with our docs? Download an LLM-friendly text file of our full documentation and include it in your system prompt.

In the examples below, the OpenRouter-specific headers are optional. Setting them allows your app to appear on the OpenRouter leaderboards.

Using the OpenAI SDK

1 from openai import OpenAI
2 
3 client = OpenAI(
4   base_url="https://openrouter.ai/api/v1",
5   api_key="<OPENROUTER_API_KEY>",
6 )
7 
8 completion = client.chat.completions.create(
9   extra_headers={
10     "HTTP-Referer": "<YOUR_SITE_URL>", # Optional. Site URL for rankings on openrouter.ai.
11     "X-Title": "<YOUR_SITE_NAME>", # Optional. Site title for rankings on openrouter.ai.
12   },
13   model="openai/gpt-4o",
14   messages=[
15     {
16       "role": "user",
17       "content": "What is the meaning of life?"
18     }
19   ]
20 )
21 
22 print(completion.choices[0].message.content)

Using the OpenRouter API directly

1 import requests
2 import json
3 
4 response = requests.post(
5   url="https://openrouter.ai/api/v1/chat/completions",
6   headers={
7     "Authorization": "Bearer <OPENROUTER_API_KEY>",
8     "HTTP-Referer": "<YOUR_SITE_URL>", # Optional. Site URL for rankings on openrouter.ai.
9     "X-Title": "<YOUR_SITE_NAME>", # Optional. Site title for rankings on openrouter.ai.
10   },
11   data=json.dumps({
12     "model": "openai/gpt-4o", # Optional
13     "messages": [
14       {
15         "role": "user",
16         "content": "What is the meaning of life?"
17       }
18     ]
19   })
20 )

The API also supports streaming.

Using third-party SDKs

For information about using third-party SDKs and frameworks with OpenRouter, please see our frameworks documentation.

1	from openai import OpenAI
2
3	client = OpenAI(
4	base_url="https://openrouter.ai/api/v1",
5	api_key="<OPENROUTER_API_KEY>",
6	)
7
8	completion = client.chat.completions.create(
9	extra_headers={
10	"HTTP-Referer": "<YOUR_SITE_URL>", # Optional. Site URL for rankings on openrouter.ai.
11	"X-Title": "<YOUR_SITE_NAME>", # Optional. Site title for rankings on openrouter.ai.
12	},
13	model="openai/gpt-4o",
14	messages=[
15	{
16	"role": "user",
17	"content": "What is the meaning of life?"
18	}
19	]
20	)
21
22	print(completion.choices[0].message.content)

1	import requests
2	import json
3
4	response = requests.post(
5	url="https://openrouter.ai/api/v1/chat/completions",
6	headers={
7	"Authorization": "Bearer <OPENROUTER_API_KEY>",
8	"HTTP-Referer": "<YOUR_SITE_URL>", # Optional. Site URL for rankings on openrouter.ai.
9	"X-Title": "<YOUR_SITE_NAME>", # Optional. Site title for rankings on openrouter.ai.
10	},
11	data=json.dumps({
12	"model": "openai/gpt-4o", # Optional
13	"messages": [
14	{
15	"role": "user",
16	"content": "What is the meaning of life?"
17	}
18	]
19	})
20	)