> ## Documentation Index
> Fetch the complete documentation index at: https://docs.samplehc.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment Variables

> Managing environment variables in Sample Workflows

## Overview

Environment variables in Sample Workflows provide a secure way to manage configuration values, API keys, and other sensitive data that your workflow needs to access. These variables are **injected at deploy time** and are only available within your workflow code.

<img src="https://mintcdn.com/sample-d81c0ba9/wakilrt7leTVRJLZ/static/workflows/environment-variables.png?fit=max&auto=format&n=wakilrt7leTVRJLZ&q=85&s=8ee78b7b7e59ca5b2f48eb5b9477b132" alt="title" width="1800" height="1174" data-path="static/workflows/environment-variables.png" />

## How Environment Variables Work

### Deployment-Time Injection

Environment variables are injected into your workflow when it's deployed to the Sample platform. This means:

* They become available to your workflow code after deployment
* Changes to environment variables require a new deployment to take effect

### Accessing Environment Variables

In your workflow code, you can access environment variables using Python's built-in `os.getenv()` function:

```python theme={null}
import os
from workflows_py.workflow import Workflow, Step

def process_with_api_key(ctx):
    # Access environment variables
    api_key = os.getenv("API_KEY")
    database_url = os.getenv("DATABASE_URL")
    debug_mode = os.getenv("DEBUG_MODE", "false")  # with default value

    if not api_key:
        raise ValueError("API_KEY environment variable is required")

    # Use the environment variables in your logic
    response = make_api_call(api_key, database_url)
    return {"result": response}

workflow = Workflow()
workflow.then(
    Step("api-call", process_with_api_key)
)
```

## Best Practices

### Security Considerations

1. **Never hardcode sensitive values** in your workflow code
2. **Use environment variables** for API keys, tokens, and connection strings
3. **Set appropriate access controls** for who can view and modify environment variables

### Naming Conventions

1. **Use UPPERCASE** with underscores for environment variable names
2. **Be descriptive** but concise: `DATABASE_URL`, `STRIPE_API_KEY`
3. **Group related variables** with prefixes: `AWS_ACCESS_KEY`, `AWS_SECRET_KEY`

### Default Values

Always provide sensible defaults when possible:

```python theme={null}
# Good: Provides a default value
debug_mode = os.getenv("DEBUG_MODE", "false")
timeout = int(os.getenv("API_TIMEOUT", "30"))

# Better: Handle missing required variables gracefully
api_key = os.getenv("API_KEY")
if not api_key:
    raise ValueError("API_KEY environment variable is required")
```

## Common Use Cases

### API Integration

```python theme={null}
def call_external_api(ctx):
    api_key = os.getenv("EXTERNAL_API_KEY")
    base_url = os.getenv("EXTERNAL_API_URL", "https://api.example.com")

    headers = {"Authorization": f"Bearer {api_key}"}
    # Make API calls using the configured values
```

### Database Connections

```python theme={null}
def connect_to_database(ctx):
    db_url = os.getenv("DATABASE_URL")
    db_timeout = int(os.getenv("DB_TIMEOUT", "10"))

    # Use connection parameters
    connection = create_connection(db_url, timeout=db_timeout)
```

### Feature Flags

```python theme={null}
def conditional_processing(ctx):
    feature_enabled = os.getenv("FEATURE_X_ENABLED", "false").lower() == "true"

    if feature_enabled:
        # Execute new feature logic
        return process_with_new_feature(ctx)
    else:
        # Execute legacy logic
        return process_with_legacy_feature(ctx)
```

This allows your workflow code to remain the same across environments while adapting to different configurations.

## Important Notes

* Environment variables are **only available in workflow code**, not in screen components
* Changes to environment variables **require redeployment** to take effect
* Environment variables are **scoped to the specific workflow** and environment
* Use the Sample platform's environment variable management interface to set and update values securely