Eager to get started? This page gives a good introduction to Flask-WTF. It assumes you already have Flask-WTF installed. If you do not, head over to the Installation section.

Creating Forms

Flask-WTF provides your Flask application integration with WTForms. For example:

from flask_wtf import FlaskForm
from wtforms import StringField
from wtforms.validators import DataRequired

class MyForm(FlaskForm):
    name = StringField('name', validators=[DataRequired()])


From version 0.9.0, Flask-WTF will not import anything from wtforms, you need to import fields from wtforms.

In addition, a CSRF token hidden field is created automatically. You can render this in your template:

<form method="POST" action="/">
    {{ form.csrf_token }}
    {{ form.name.label }} {{ form.name(size=20) }}
    <input type="submit" value="Go">

If your form has multiple hidden fields, you can render them in one block using hidden_tag().

<form method="POST" action="/">
    {{ form.hidden_tag() }}
    {{ form.name.label }} {{ form.name(size=20) }}
    <input type="submit" value="Go">

Validating Forms

Validating the request in your view handlers:

@app.route('/submit', methods=['GET', 'POST'])
def submit():
    form = MyForm()
    if form.validate_on_submit():
        return redirect('/success')
    return render_template('submit.html', form=form)

Note that you don’t have to pass request.form to Flask-WTF; it will load automatically. And the convenient validate_on_submit will check if it is a POST request and if it is valid.

If your forms include validation, you’ll need to add to your template to display any error messages. Using the form.name field from the example above, that would look like this:

{% if form.name.errors %}
    <ul class="errors">
    {% for error in form.name.errors %}
        <li>{{ error }}</li>
    {% endfor %}
{% endif %}

Heading over to Creating Forms to learn more skills.