Get the data received in a Flask request


I want to be able to get the data sent to my Flask app. I’ve tried accessing but it is an empty string. How do you access request data?

from flask import request

@app.route('/', methods=['GET', 'POST'])
def parse_request():
    data =  # data is empty
    # need posted data here

The answer to this question led me to ask Get raw POST body in Python Flask regardless of Content-Type header next, which is about getting the raw data rather than the parsed data.

Asked By: ddinchev



To get the raw data, use This only works if it couldn’t be parsed as form data, otherwise it will be empty and request.form will have the parsed data.

from flask import request
Answered By: clyfish

The docs describe the attributes available on the request object (from flask import request) during a request. In most common cases will be empty because it’s used as a fallback: Contains the incoming request data as string in case it came with a mimetype Flask does not handle.

  • request.args: the key/value pairs in the URL query string
  • request.form: the key/value pairs in the body, from a HTML post form, or JavaScript request that isn’t JSON encoded
  • request.files: the files in the body, which Flask keeps separate from form. HTML forms must use enctype=multipart/form-data or files will not be uploaded.
  • request.values: combined args and form, preferring args if keys overlap
  • request.json: parsed JSON data. The request must have the application/json content type, or use request.get_json(force=True) to ignore the content type.

All of these are MultiDict instances (except for json). You can access values using:

  • request.form['name']: use indexing if you know the key exists
  • request.form.get('name'): use get if the key might not exist
  • request.form.getlist('name'): use getlist if the key is sent multiple times and you want a list of values. get only returns the first value.
Answered By: Robert

For URL query parameters, use request.args.

search = request.args.get("search")
page = request.args.get("page")

For posted form input, use request.form.

email = request.form.get('email')
password = request.form.get('password')

For JSON posted with content type application/json, use request.get_json().

data = request.get_json()
Answered By: Fizer Khan

If you post JSON with content type application/json, use request.get_json() to get it in Flask. If the content type is not correct, None is returned. If the data is not JSON, an error is raised.

@app.route("/something", methods=["POST"])
def do_something():
    data = request.get_json()
Answered By: Amitkumar Karnik

To get the raw post body regardless of the content type, use request.get_data(). If you use, it calls request.get_data(parse_form_data=True), which will populate the request.form MultiDict and leave data empty.

Answered By: Xiao

The raw data is passed in to the Flask application from the WSGI server as The length of the stream is in the Content-Length header.

length = request.headers["Content-Length"]
data =

It is usually safer to use request.get_data() instead.

Answered By: Daniel

Here’s an example of parsing posted JSON data and echoing it back.

from flask import Flask, request, jsonify

app = Flask(__name__)

@app.route('/foo', methods=['POST']) 
def foo():
    data = request.json
    return jsonify(data)

To post JSON with curl:

curl -i -H "Content-Type: application/json" -X POST -d '{"userId":"1", "username": "fizz bizz"}' http://localhost:5000/foo

Or to use Postman:

using postman to post JSON

Answered By: Little Roys

To parse JSON, use request.get_json().

@app.route("/something", methods=["POST"])
def do_something():
    result = handle(request.get_json())
    return jsonify(data=result)
Answered By: zhangqy

To get JSON posted without the application/json content type, use request.get_json(force=True).

@app.route('/process_data', methods=['POST'])
def process_data():
    req_data = request.get_json(force=True)
    language = req_data['language']
    return 'The language value is: {}'.format(language)
Answered By: Tarik Fojnica

To post JSON with jQuery in JavaScript, use JSON.stringify to dump the data, and set the content type to application/json.

var value_data = [1, 2, 3, 4];

    type: 'POST',
    url: '/process',
    data: JSON.stringify(value_data),
    contentType: 'application/json',
    success: function (response_data) {

Parse it in Flask with request.get_json().

data = request.get_json()
Answered By: vaishali chaudhari

To get request.form as a normal dictionary , use request.form.to_dict(flat=False).

To return JSON data for an API, pass it to jsonify.

This example returns form data as JSON data.

@app.route('/form_to_json', methods=['POST'])
def form_to_json():
    data = request.form.to_dict(flat=False)
    return jsonify(data)

Here’s an example of POST form data with curl, returning as JSON:

$ curl -d "name=ivanleoncz&role=Software Developer"
  "name": "ivanleoncz", 
  "role": "Software Developer"
Answered By: ivanleoncz

When posting form data with an HTML form, be sure the input tags have name attributes, otherwise they won’t be present in request.form.

@app.route('/', methods=['GET', 'POST'])
def index():
    return """
<form method="post">
    <input type="text">
    <input type="text" id="txt2">
    <input type="text" name="txt3" id="txt3">  
    <input type="submit">
ImmutableMultiDict([('txt3', 'text 3')])

Only the txt3 input had a name, so it’s the only key present in request.form.

Answered By: freezed

If the content type is recognized as form data, will parse that into request.form and return an empty string.

To get the raw data regardless of content type, call request.get_data(). calls get_data(parse_form_data=True), while the default is False if you call it directly.

Answered By: Zavec

If the body is recognized as form data, it will be in request.form. If it’s JSON, it will be in request.get_json(). Otherwise the raw data will be in If you’re not sure how data will be submitted, you can use an or chain to get the first one with data.

def get_request_data():
    return (
        or request.form
        or request.get_json(force=True, silent=True)

request.args contains args parsed from the query string, regardless of what was in the body, so you would remove that from get_request_data() if both it and a body should data at the same time.

Answered By: Paul Gowder

Use request.get_json() to get posted JSON data.

data = request.get_json()
name = data.get('name', '')

Use request.form to get data when submitting a form with the POST method.

name = request.form.get('name', '')

Use request.args to get data passed in the query string of the URL, like when submitting a form with the GET method.

request.args.get("name", "")

request.form etc. are dict-like, use the get method to get a value with a default if it wasn’t passed.

Answered By: Ravin Gupta

Here’s an example of posting form data to add a user to a database. Check request.method == "POST" to check if the form was submitted. Use keys from request.form to get the form data. Render an HTML template with a <form> otherwise. The fields in the form should have name attributes that match the keys in request.form.

from flask import Flask, request, render_template

app = Flask(__name__)

@app.route("/user/add", methods=["GET", "POST"])
def add_user():
    if request.method == "POST":
        user = User(
        return redirect(url_for("index"))

    return render_template("add_user.html")
<form method="post">
    <label for="username">Username</label>
    <input type="text" name="username" id="username">
    <label for="email">Email</label>
    <input type="email" name="email" id="email">
    <input type="submit">
Answered By: Dulangi_Kanchana
@app.route('/addData', methods=['POST'])
def add_data():
     data_in = mongo.db.Data
     id = request.values.get("id")
     name = request.values.get("name")
     newuser = {'id' : id, 'name' : name}
     if voter.find({'id' : id, 'name' : name}).count() > 0:
            return "Data Exists"
            return "Data Added"
Answered By: Divyani Singh

When writing a Slack bot, which is supposed to send JSON data, I got a payload where the Content-Type was application/x-www-form-urlencoded.

I tried request.get_json() and it didn’t work.

@app.route('/process_data', methods=['POST'])
def process_data():
   req_data = request.get_json(force=True)

Instead I used request.form to get the form data field that contained JSON, then loaded that.

from flask import json

@ app.route('/slack/request_handler', methods=['POST'])
def request_handler():
   req_data = json.loads(request.form["payload"])
Answered By: Phoebe

This is great to use but remember that it comes in as a string and will need iterated through.

Answered By: James

Import request:

from flask import request

URL query parameters:

name = request.args.get("name")
age = request.args.get("age")

Form Input:

name = request.form.get('name')
age = request.form.get('age')

OR (use indexing if you know the key exists, specify the name of input fields)

name = request.form['name']
age = request.form['age']

JSON Data (for content type application/json)

data = request.get_json()
Answered By: Murad

Try – >

from flask import request

@app.route('/', methods=['GET', 'POST'])
def parse_request():
    if request.method == 'POST':
       data = request.form.get('data')
Answered By: Nimit Gupta

You can get request data from

  1. request.form for form data, this includes form and file data,
  2. request.json and request.get_json for JSON data
  3. request.headers for headers
  4. request.args to get query params

They’re all like a dictionary, use request.form['name'] if you know the key exists, or request.form.get('name') if it is optional.

Answered By: bkoiki950

I just faced the same need. I have to save information in case of any unexpected situation. So, I use the following formula:

Info = "%s/%s/%s" % (request.remote_addr, repr(request), repr(session))

repr(request) will give a string representation of the basic information. You could add user-agent data with:

I also save the session continent as it could contain valuable information

Answered By: Rapace-bleu

With all these good answers, is still couldn’t find why it didn’t work for me.
The solution was in debugging.
Though this is not "THE" answer, this is a link to the video that helped me debug my work on vscode, and therefore find the right way to get the data passed from ajax

Answered By: Shefy Gur-ary
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