Environment Variables

The pythonanywhere-core library uses several environment variables for configuration.

Required Variables

API_TOKEN

Required: Yes

Description: Your PythonAnywhere API token used for authentication with the PythonAnywhere API.

How to obtain:

  1. Log into your PythonAnywhere account

  2. Go to the “Account” page

  3. Navigate to the “API Token” tab

  4. Click “Create a new API token”

Usage:

export API_TOKEN="your_token_here"
Exceptions:

  • If not set, raises NoTokenError

  • If invalid, API calls will raise AuthenticationError

Optional Variables

PYTHONANYWHERE_CLIENT

Required: No

Default: Not set (library identifies itself without client information)

Description: Identifies the client application using pythonanywhere-core in API requests. This information is included in the User-Agent header and helps PythonAnywhere understand API usage patterns and improve service analytics.

Format: client-name/version (e.g., pa/1.0.0, mcp-server/0.5.0)

When to use:

  • Building a CLI tool that uses this library

  • Creating an MCP server

  • Developing automation scripts or custom applications

  • Any downstream tool that wraps pythonanywhere-core

User-Agent format:

  • Without PYTHONANYWHERE_CLIENT: pythonanywhere-core/0.2.8 (Python/3.13.7)

  • With PYTHONANYWHERE_CLIENT: pythonanywhere-core/0.2.8 (pa/1.0.0; Python/3.13.7)

Usage:

import os
from importlib.metadata import version

# Set at application startup
CLI_VERSION = version("my-cli-package")
os.environ["PYTHONANYWHERE_CLIENT"] = f"my-cli/{CLI_VERSION}"

PYTHONANYWHERE_DOMAIN

Required: No

Default: pythonanywhere.com

Description: Override the domain used for constructing the API hostname. Used in combination with the site hostname. Only used when PYTHONANYWHERE_SITE is not set.

Note

When running on PythonAnywhere, this variable is automatically set in the environment to match your domain (e.g., pythonanywhere.com).

Usage:

export PYTHONANYWHERE_DOMAIN="example.com"

PYTHONANYWHERE_SITE

Required: No

Default: www.pythonanywhere.com (or www. + PYTHONANYWHERE_DOMAIN if that is set)

Description: Override the hostname used for API requests. Useful for testing against different PythonAnywhere environments or when using EU servers.

Note

When running on PythonAnywhere, this variable is automatically set in the environment to match your system location (e.g., www.pythonanywhere.com or eu.pythonanywhere.com).

Usage:

export PYTHONANYWHERE_SITE="eu.pythonanywhere.com"

PYTHONANYWHERE_USERNAME

Required: No

Default: The current system username (via getpass.getuser())

Description: Override the PythonAnywhere username used for constructing API endpoints. When running outside of PythonAnywhere (e.g., from a local machine), the system username often won’t match your PythonAnywhere username, so this variable lets you specify the correct one.

Usage:

export PYTHONANYWHERE_USERNAME="your_pa_username"

See Also

  • Exceptions - Exception types raised when environment variables are missing or invalid

  • Base - The call_api function that uses these variables