[mvolfik]

How are these set in werkzeug? Sound like you would be using the werkzeug dev server then...

But this works for me:

    @app.errorhandler(ApplicationError)
    def handle(e):
        resp = e.args[0]
        resp.headers["Access-Control-Allow-Origin"] = "..."
        resp.status_code = 500
        return resp

    @app.route("/err")
    def err():
        raise ApplicationError(jsonify({"reason": "test"}))

[rastapasta42]

I'm aware about the ability to overwrite error handler with a custom code, but Werkzeug's handler already supports pretty stack traces and much more, and I would rather not re-invent the wheel from scratch.

I was talking about using werkzeug's builtin exception handler but with custom headers - which doesn't appear to be supported.

[mvolfik]

that is not supported. But why would you want to serve that with CORS headers? It's only meant to be displayed in the browser and in dev environment, not production