docs/my-website/src/pages/index.md

import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

# LiteLLM - Getting Started

https://github.com/BerriAI/litellm


## **Call 100+ LLMs using the same Input/Output Format**

## Basic usage 
<a target="_blank" href="https://colab.research.google.com/github/BerriAI/litellm/blob/main/cookbook/liteLLM_Getting_Started.ipynb">
  <img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab"/>
</a>

```shell
pip install litellm
```
<Tabs>
<TabItem value="openai" label="OpenAI">

```python
from litellm import completion
import os

## set ENV variables
os.environ["OPENAI_API_KEY"] = "your-api-key"

response = completion(
  model="gpt-3.5-turbo", 
  messages=[{ "content": "Hello, how are you?","role": "user"}]
)
```

</TabItem>
<TabItem value="anthropic" label="Anthropic">

```python
from litellm import completion
import os

## set ENV variables
os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

response = completion(
  model="claude-2", 
  messages=[{ "content": "Hello, how are you?","role": "user"}]
)
```

</TabItem>

<TabItem value="vertex" label="VertexAI">

```python
from litellm import completion
import os

# auth: run 'gcloud auth application-default'
os.environ["VERTEX_PROJECT"] = "hardy-device-386718"
os.environ["VERTEX_LOCATION"] = "us-central1"

response = completion(
  model="chat-bison", 
  messages=[{ "content": "Hello, how are you?","role": "user"}]
)
```

</TabItem>

<TabItem value="hugging" label="HuggingFace">

```python
from litellm import completion 
import os

os.environ["HUGGINGFACE_API_KEY"] = "huggingface_api_key" 

# e.g. Call 'WizardLM/WizardCoder-Python-34B-V1.0' hosted on HF Inference endpoints
response = completion(
  model="huggingface/WizardLM/WizardCoder-Python-34B-V1.0",
  messages=[{ "content": "Hello, how are you?","role": "user"}], 
  api_base="https://my-endpoint.huggingface.cloud"
)

print(response)
```

</TabItem>

<TabItem value="azure" label="Azure OpenAI">

```python
from litellm import completion
import os

## set ENV variables
os.environ["AZURE_API_KEY"] = ""
os.environ["AZURE_API_BASE"] = ""
os.environ["AZURE_API_VERSION"] = ""

# azure call
response = completion(
  "azure/<your_deployment_name>", 
  messages = [{ "content": "Hello, how are you?","role": "user"}]
)
```

</TabItem>


<TabItem value="ollama" label="Ollama">

```python
from litellm import completion

response = completion(
            model="ollama/llama2", 
            messages = [{ "content": "Hello, how are you?","role": "user"}], 
            api_base="http://localhost:11434"
)
```
</TabItem>
<TabItem value="or" label="Openrouter">

```python
from litellm import completion
import os

## set ENV variables
os.environ["OPENROUTER_API_KEY"] = "openrouter_api_key" 

response = completion(
  model="openrouter/google/palm-2-chat-bison", 
  messages = [{ "content": "Hello, how are you?","role": "user"}],
)
```
</TabItem>

</Tabs>

## Streaming
Set `stream=True` in the `completion` args. 
<Tabs>
<TabItem value="openai" label="OpenAI">

```python
from litellm import completion
import os

## set ENV variables
os.environ["OPENAI_API_KEY"] = "your-api-key"

response = completion(
  model="gpt-3.5-turbo", 
  messages=[{ "content": "Hello, how are you?","role": "user"}],
  stream=True,
)
```

</TabItem>
<TabItem value="anthropic" label="Anthropic">

```python
from litellm import completion
import os

## set ENV variables
os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

response = completion(
  model="claude-2", 
  messages=[{ "content": "Hello, how are you?","role": "user"}],
  stream=True,
)
```

</TabItem>

<TabItem value="vertex" label="VertexAI">

```python
from litellm import completion
import os

# auth: run 'gcloud auth application-default'
os.environ["VERTEX_PROJECT"] = "hardy-device-386718"
os.environ["VERTEX_LOCATION"] = "us-central1"

response = completion(
  model="chat-bison", 
  messages=[{ "content": "Hello, how are you?","role": "user"}],
  stream=True,
)
```

</TabItem>

<TabItem value="hugging" label="HuggingFace">

```python
from litellm import completion 
import os

os.environ["HUGGINGFACE_API_KEY"] = "huggingface_api_key" 

# e.g. Call 'WizardLM/WizardCoder-Python-34B-V1.0' hosted on HF Inference endpoints
response = completion(
  model="huggingface/WizardLM/WizardCoder-Python-34B-V1.0",
  messages=[{ "content": "Hello, how are you?","role": "user"}], 
  api_base="https://my-endpoint.huggingface.cloud",
  stream=True,
)

print(response)
```

</TabItem>

<TabItem value="azure" label="Azure OpenAI">

```python
from litellm import completion
import os

## set ENV variables
os.environ["AZURE_API_KEY"] = ""
os.environ["AZURE_API_BASE"] = ""
os.environ["AZURE_API_VERSION"] = ""

# azure call
response = completion(
  "azure/<your_deployment_name>", 
  messages = [{ "content": "Hello, how are you?","role": "user"}],
  stream=True,
)
```

</TabItem>


<TabItem value="ollama" label="Ollama">

```python
from litellm import completion

response = completion(
            model="ollama/llama2", 
            messages = [{ "content": "Hello, how are you?","role": "user"}], 
            api_base="http://localhost:11434",
            stream=True,
)
```
</TabItem>
<TabItem value="or" label="Openrouter">

```python
from litellm import completion
import os

## set ENV variables
os.environ["OPENROUTER_API_KEY"] = "openrouter_api_key" 

response = completion(
  model="openrouter/google/palm-2-chat-bison", 
  messages = [{ "content": "Hello, how are you?","role": "user"}],
  stream=True,
)
```
</TabItem>

</Tabs>

## Exception handling 

LiteLLM maps exceptions across all supported providers to the OpenAI exceptions. All our exceptions inherit from OpenAI's exception types, so any error-handling you have for that, should work out of the box with LiteLLM. 

```python 
from openai.error import OpenAIError
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "bad-key"
try: 
    # some code 
    completion(model="claude-instant-1", messages=[{"role": "user", "content": "Hey, how's it going?"}])
except OpenAIError as e:
    print(e)
```

## Logging Observability - Log LLM Input/Output ([Docs](https://docs.litellm.ai/docs/observability/callbacks))
LiteLLM exposes pre defined callbacks to send data to Langfuse, LLMonitor, Helicone, Promptlayer, Traceloop, Slack
```python
from litellm import completion

## set env variables for logging tools
os.environ["LANGFUSE_PUBLIC_KEY"] = ""
os.environ["LANGFUSE_SECRET_KEY"] = ""
os.environ["LLMONITOR_APP_ID"] = "your-llmonitor-app-id"

os.environ["OPENAI_API_KEY"]

# set callbacks
litellm.success_callback = ["langfuse", "llmonitor"] # log input/output to langfuse, llmonitor, supabase

#openai call
response = completion(model="gpt-3.5-turbo", messages=[{"role": "user", "content": "Hi 👋 - i'm openai"}])
```

## Calculate Costs, Usage, Latency

Pass the completion response to `litellm.completion_cost(completion_response=response)` and get the cost

```python
from litellm import completion, completion_cost
import os
os.environ["OPENAI_API_KEY"] = "your-api-key"

response = completion(
  model="gpt-3.5-turbo", 
  messages=[{ "content": "Hello, how are you?","role": "user"}]
)

cost = completion_cost(completion_response=response)
print("Cost for completion call with gpt-3.5-turbo: ", f"${float(cost):.10f}")
```

**Output**
```shell
Cost for completion call with gpt-3.5-turbo:  $0.0000775000
```

### Track Costs, Usage, Latency for streaming
Use a callback function for this - more info on custom callbacks: https://docs.litellm.ai/docs/observability/custom_callback

```python
import litellm

# track_cost_callback 
def track_cost_callback(
    kwargs,                 # kwargs to completion
    completion_response,    # response from completion
    start_time, end_time    # start/end time
):
    try:
        # check if it has collected an entire stream response
        if "complete_streaming_response" in kwargs:
            # for tracking streaming cost we pass the "messages" and the output_text to litellm.completion_cost 
            completion_response=kwargs["complete_streaming_response"]
            input_text = kwargs["messages"]
            output_text = completion_response["choices"][0]["message"]["content"]
            response_cost = litellm.completion_cost(
                model = kwargs["model"],
                messages = input_text,
                completion=output_text
            )
            print("streaming response_cost", response_cost)
    except:
        pass
# set callback 
litellm.success_callback = [track_cost_callback] # set custom callback function

# litellm.completion() call
response = completion(
    model="gpt-3.5-turbo",
    messages=[
        {
            "role": "user",
            "content": "Hi 👋 - i'm openai"
        }
    ],
    stream=True
)
```


Need a dedicated key? Email us @ [email protected]


## More details
* [exception mapping](./exception_mapping.md)
* [retries + model fallbacks for completion()](./completion/reliable_completions.md)
* [tutorial for model fallbacks with completion()](./tutorials/fallbacks.md)