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POSTing JSON data

Learn how to send an HTTP POST request with a JSON data payload using LoadForge.

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Using LoadForge, sending HTTP POST requests with JSON data is straightforward. Before making the request, you need to prepare and parse your JSON data. This documentation will guide you on how to send a POST request with JSON data using LoadForge.

Preparing JSON Data for POST Request

To send JSON data via an HTTP POST request, the data needs to be serialized before transmission. In Python, you can utilize the json.dumps() method to serialize your data.

In addition to preparing your data, you should also set the content type of your request to application/json in the headers to inform the receiving server that you're sending JSON data.

Example: Posting JSON Data to an Endpoint

In the provided example, a payload consisting of two key-value pairs will be posted to the /post/endpoint. Follow the steps and the code sample below:

  1. Setup and Imports
    Start by importing necessary modules like time, json, and relevant locust classes.

  2. Define User Behavior
    Create a class (QuickstartUser) that extends the HttpUser class from Locust. This will define the behavior of a simulated user.

  3. Set Waiting Time
    Use wait_time to simulate the wait period between tasks. This example uses a randomized wait time of 3 to 5 seconds.

  4. Define the Task
    Within the user class, define a task named api_page. This task sends a POST request with the payload.

import time, json
from locust import HttpUser, task, between

class QuickstartUser(HttpUser):
    wait_time = between(3, 5)

    def api_page(self):
        payload = {
            'key': 'value',
            'question': 'answer123'

        headers = {'content-type': 'application/json'}

        response = self.client.post(

Note: There was a missing comma in the payload dictionary which has been corrected in the example above.

Power of Locust in LoadForge

LoadForge is built on top of locust.io, allowing you to leverage the full capabilities of the open-source Locust framework. If you're already using Locust, consider importing your scripts to LoadForge to enhance and simplify your load testing process.

By following the above instructions, you can effectively send POST requests with JSON data using LoadForge. Remember always to prepare your data and set the appropriate headers to ensure successful data transmission.

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