Welcome to Flask-Inertia’s documentation

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Inertiajs Adapter for Flask.


$ pip install flask-inertia


The module needs to be initialized the usual Flask way and can be configured using app.config keys:

from flask import Flask
from flask_inertia import Inertia

SECRET_KEY = "secret!"
# mandatory key
INERTIA_TEMPLATE = "base.html"

app = Flask(__name__)

inertia = Inertia()
# or inertia = Inertia(app)

The config key INERTIA_TEMPLATE must be used to set globally the template used by flask_inertia to render the server responses. This template must exists in the Flask app templates folder.


For more information about InertiaJS, please read the docs provided by Inertia.

Whereas the Rails and Laravel adapters use a middleware to manage Inertia’s requests, this module doesn’t. Once it has been initiliazed it will create before_request and after_request hooks for your app to handle InertiaJS frontend requests.

Your templates

You will need to setup the root template that will be loaded on the first page visit. It will be used to load your site assets (CSS and JavaScript), and will also contain a root <div> to boot your JavaScript application in.

<!DOCTYPE html>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
    <title>My app</title>
    <link href="{{ url_for('static', filename='/css/app.css') }}" rel="stylesheet" />
    <script lang="javascript">
      {{ inertia.include_router() }}
    <div id="app" data-page='{{ page | tojson }}'></div>
    <script src="{{ url_for('static', filename='/js/app.js') }}" defer></script>


Be aware of the single quotes used for the data-page argument. Jinja2 will not escape the double quotes of your JSON object https://github.com/pallets/flask/issues/1002

Your root div must set a HTML data-page attribute. It will be used by Flask, using a Page JSON object to communicate with Inertia.

To facilitate the route path resolving, the module provide a template context method called inertia.include_router. It will expose the Flask views resolution (like the url_for method) to your frontend Components.

This method has been extracted to django-js-routes package and works the same way via a window.reverseUrl JavaScript method ( https://github.com/ellmetha/django-js-routes#usage).

Create responses

This module provides a method render_inertia to render your frontend component through Flask responses. It will wrap your Responses and act accordingly to Inertia requests context responding a full html or a JSON reponse. It will be used instead of Flask render_template method:

from flask_inertia import render_inertia

def test_inertia():
    """An endpoint to test inertia integration."""
    data = {
        "username": "foo",
        "login": "bar",
    return render_inertia(

This method take 2 arguments:

  • component_name: Your frontend component name (eg “Index” for an Index.vue Component for example)

  • props: [OPTIONAL] Data used by your component

Share data between requests

Sometimes you need to access certain data on numerous pages within your application. For example, a common use-case for this is showing the current user in the site header. Passing this data manually in each response isn’t practical. In these situations shared data can be useful.

This module provides a share method into the Inertia class to preassign shared data for each request. Shared data will be automatically merged with the page props provided in your controller. It takes as argument a key/value pair to serialize it in JSON in the responses.

You can set the shared data statically or programmatically using the method as followed:

inertia = Inertia(app)

# set statically a shared data
inertia.share("foo", "bar")

# or a computed value
def shared_value():
    return "buzz"

inertia.share("fizz", shared_value)

If the value is a callable, the module will resolve it during the response resolution.

To see a complete exemple on how to implement a project with this adapter, please read our Tutorial or check this demo project.