Flask: How to serve static html?

All the answers are good but what worked well for me is just using the simple function send_file from Flask. This works well when you just need to send an html file as response when host:port/ApiName will show the output of the file in browser

@app.route('/ApiName')
def ApiFunc():
    try:
        #return send_file('relAdmin/login.html')
        return send_file('some-other-directory-than-root/your-file.extension')
    except Exception as e:
        logging.info(e.args[0])```

Reducing this to the simplest method that'll work:

1. Put static assets into your static subfolder.
2. Leave Flask set to the default, don't give it a static_url_path either.
3. Access static content over the pre-configured /static/ to verify the file works

If you then still want to reuse a static file, use current_app.send_static_file(), and do not use leading / slashes:

from flask import Flask, current_app
app = Flask(__name__)

@app.route('/')
def hello_world():
    return current_app.send_static_file('editor.html')

This looks for the file editor.html directly inside the static folder.

This presumes that you saved the above file in a folder that has a static subfolder with a file editor.html inside that subfolder.

Some further notes:

• static_url_path changes the URL static files are available at, not the location on the filesystem used to load the data from.
• render_template() assumes your file is a Jinja2 template; if it is really just a static file then that is overkill and can lead to errors if there is actual executable syntax in that file that has errors or is missing context.