[python] Flask raises TemplateNotFound error even though template file exists

I am trying to render the file home.html. The file exists in my project, but I keep getting jinja2.exceptions.TemplateNotFound: home.html when I try to render it. Why can't Flask find my template?

from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def home():
    return render_template('home.html')

/myproject
    app.py
    home.html

If you run your code from an installed package, make sure template files are present in directory <python root>/lib/site-packages/your-package/templates.

Some details:

In my case I was trying to run examples of project flask_simple_ui and jinja would always say

jinja2.exceptions.TemplateNotFound: form.html

The trick was that sample program would import installed package flask_simple_ui. And ninja being used from inside that package is using as root directory for lookup the package path, in my case ...python/lib/site-packages/flask_simple_ui, instead of os.getcwd() as one would expect.

To my bad luck, setup.py has a bug and doesn't copy any html files, including the missing form.html. Once I fixed setup.py, the problem with TemplateNotFound vanished.

I hope it helps someone.

Check that:

1. the template file has the right name
2. the template file is in a subdirectory called templates
3. the name you pass to render_template is relative to the template directory (index.html would be directly in the templates directory, auth/login.html would be under the auth directory in the templates directory.)
4. you either do not have a subdirectory with the same name as your app, or the templates directory is inside that subdir.

If that doesn't work, turn on debugging (app.debug = True) which might help figure out what's wrong.

(Please note that the above accepted Answer provided for file/project structure is absolutely correct.)

Also..

In addition to properly setting up the project file structure, we have to tell flask to look in the appropriate level of the directory hierarchy.

for example..

    app = Flask(__name__, template_folder='../templates')

    app = Flask(__name__, template_folder='../templates', static_folder='../static')

Starting with ../ moves one directory backwards and starts there.

Starting with ../../ moves two directories backwards and starts there (and so on...).

Hope this helps

When render_template() function is used it tries to search for template in the folder called templates and it throws error jinja2.exceptions.TemplateNotFound when :

1. the html file do not exist or
2. when templates folder do not exist

To solve the problem :

create a folder with name templates in the same directory where the python file is located and place the html file created in the templates folder.

I don't know why, but I had to use the following folder structure instead. I put "templates" one level up.

project/
    app/
        hello.py
        static/
            main.css
    templates/
        home.html
    venv/

This probably indicates a misconfiguration elsewhere, but I couldn't figure out what that was and this worked.

I had the same error turns out the only thing i did wrong was to name my 'templates' folder,'template' without 's'. After changing that it worked fine,dont know why its a thing but it is.

Another explanation I've figured out for myself When you create the Flask application, the folder where templates is looked for is the folder of the application according to name you've provided to Flask constructor:

app = Flask(__name__)

The __name__ here is the name of the module where application is running. So the appropriate folder will become the root one for folders search.

projects/
    yourproject/
        app/
            templates/

So if you provide instead some random name the root folder for the search will be current folder.

Another alternative is to set the root_path which fixes the problem both for templates and static folders.

root_path = Path(sys.executable).parent if getattr(sys, 'frozen', False) else Path(__file__).parent
app = Flask(__name__.split('.')[0], root_path=root_path)

If you render templates directly via Jinja2, then you write:

ENV = jinja2.Environment(loader=jinja2.FileSystemLoader(str(root_path / 'templates')))
template = ENV.get_template(your_template_name)

My problem was that the file I was referencing from inside my home.html was a .j2 instead of a .html, and when I changed it back jinja could read it.

Stupid error but it might help someone.

You need to put all you .html files in the template folder next to your python module. And if there are any images that you are using in your html files then you need put all your files in the folder named static

In the following Structure

project/
    hello.py
    static/
        image.jpg
        style.css
    templates/
        homepage.html
    virtual/
        filename.json

I think Flask uses the directory templates by default. So your code should be like this

suppose this is your hello.py

from flask import Flask,render_template

app=Flask(__name__,template_folder='template')


@app.route("/")
def home():
    return render_template('home.html')

@app.route("/about/")
def about():
    return render_template('about.html')

if __name__=="__main__":
    app.run(debug=True)

And you work space structure like

project/
    hello.py        
    template/
         home.html
         about.html    
    static/
           js/
             main.js
           css/
               main.css

also you have create two html files with name of home.html and about.html and put those files in templates folder.