httpx/docs/environment_variables.md

Environment Variables

The HTTPX library can be configured via environment variables. Environment variables are used by default. To ignore environment variables, trust_env has to be set False. There are two ways to set trust_env to disable environment variables:

• On the client via httpx.Client(trust_env=False).
• Using the top-level API, such as httpx.get("<url>", trust_env=False).

Here is a list of environment variables that HTTPX recognizes and what function they serve:

Proxies

The environment variables documented below are used as a convention by various HTTP tooling, including:

• cURL
• requests

For more information on using proxies in HTTPX, see HTTP Proxying.

HTTP_PROXY, HTTPS_PROXY, ALL_PROXY

Valid values: A URL to a proxy

HTTP_PROXY, HTTPS_PROXY, ALL_PROXY set the proxy to be used for http, https, or all requests respectively.

export HTTP_PROXY=http://my-external-proxy.com:1234

# This request will be sent through the proxy
python -c "import httpx; httpx.get('http://example.com')"

# This request will be sent directly, as we set `trust_env=False`
python -c "import httpx; httpx.get('http://example.com', trust_env=False)"

NO_PROXY

Valid values: a comma-separated list of hostnames/urls

NO_PROXY disables the proxy for specific urls

export HTTP_PROXY=http://my-external-proxy.com:1234
export NO_PROXY=http://127.0.0.1,python-httpx.org

# As in the previous example, this request will be sent through the proxy
python -c "import httpx; httpx.get('http://example.com')"

# These requests will be sent directly, bypassing the proxy
python -c "import httpx; httpx.get('http://127.0.0.1:5000/my-api')"
python -c "import httpx; httpx.get('https://www.python-httpx.org')"