# CORS Setup - Crow
Crow Allows a developer to set CORS policies by using the CORSHandler middleware.

# CORS Setup

Crow Allows a developer to set CORS policies by using the `CORSHandler` middleware.

This middleware can be added to the app simply by defining a `crow::App<crow::CORSHandler>`. This will use the default CORS rules globally

The CORS rules can be modified by first getting the middleware via `auto& cors = app.get_middleware<crow::CORSHandler>();`. The rules can be set per URL prefix using `prefix()`, per blueprint using `blueprint()`, or globally via `global()`. These will return a `CORSRules` object which contains the actual rules for the prefix, blueprint, or application. For more details go here.

`CORSRules` can be modified using the methods `origin()`, `methods()`, `headers()`, `max_age()`, `allow_credentials()`, or `ignore()`. For more details on these methods and what default values they take go here.