Requestly Tutorial: The Traffic Controller for Developers

What is Requestly?

It sounds like you've found one of the most practical tools in the GitHub Student Developer Pack. At its core, Requestly is like a "traffic controller" for your internet browser.

When developers build websites, they need to test how the site handles different situations. Requestly lets them take control of the hidden messages sent between the browser and the server.

Key Concepts

1. Intercepting Requests

When you use a website, your browser sends "requests" to a server (like asking for a photo or a list of users). Usually, this happens instantly behind the scenes.

Simple Definition: Catching a message before it reaches its destination.

The Example: Imagine you are sending a letter. Requestly acts like a friendly postal worker who catches your letter before it’s delivered so you can take a look at it or change what's inside.

2. Modifying Requests & Responses

Once Requestly "catches" that message, it allows you to change the data inside it.

Simple Definition: Editing the information being sent or received to see how a website reacts.

The Example: You are testing a website that displays a "Low Balance" warning if a user has less than $10. Instead of actually spending your money to trigger the warning, you use Requestly to modify the "Response" from the bank’s server, changing your balance from $1,000 to $5. You can then see if your website’s warning message looks correct.

3. Mocking APIs

Sometimes, the "server" or the "API" you need to talk to isn't finished yet, or it costs money every time you use it.

Simple Definition: Creating a "fake" version of a service that acts like the real thing.

The Example: You are building a weather app, but the weather service limits you to 10 checks per day. You can use Requestly to mock the weather API. Every time your app asks for the temperature, Requestly sends back a fake "72°F" instantly. This lets you keep building your app without hitting limits or waiting for a real server.

4. Open-Source

The text mentions Requestly is "open-source."

Simple Definition: The "blueprints" (code) of the tool are public. Anyone can see how it's built, suggest improvements, or check that it’s safe to use.

GitHub Student Offer

The Professional Plan usually costs $270 per year, but as a student, you get it for free. This version typically allows you to:

Share your "rules" with teammates.
Store more "mock" data in the cloud.
Access advanced features for testing mobile apps.

Tutorial: How to Create Your First Redirect Rule

Ready to try it out? A "Redirect Rule" is the simplest way to start. It tells your browser: "When you try to go to URL A, go to URL B instead."

Scenario: Let's say you want to test if your code works with a newer version of a library, or maybe you just want to redirect a search engine for fun. In this example, we will redirect bing.com to google.com.

Install Requestly
First, make sure you have the Requestly browser extension installed from the Chrome Web Store or Firefox Add-ons.
Open the Dashboard
Click on the Requestly icon in your browser toolbar and select "Open App" or go directly to app.requestly.io.
Create a New Rule
On the dashboard, look for the "New Rule" button (usually top right) and click it.
Select "Redirect Request"
You will see a list of rule types. Select "Redirect Request". This is the most common rule type for beginners.
Configure the Rule
You need to tell Requestly what to look for and where to send it.

Request URL (Contains/Equals): Enter bing.com

Destination: Enter https://www.google.com
Save and Test
Click the "Save Rule" button. Now, open a new tab and type bing.com. Watch as it magically loads Google instead!

Congratulations! You've just successfully intercepted and modified a network request.

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Mastering Requestly