Ever wondered what data a website is actually sending and receiving behind the scenes? Every time a page loads, your browser fires off dozens of network requests — for images, scripts, and API calls carrying real data. Chrome DevTools lets you watch all of it live. Here's how, in plain steps.
What you'll learn
- How to open the Network tab
- How to read a single request (headers, response, timing)
- How to filter to just the requests you care about (like API calls)
- A few pro tricks that save hours of debugging
Step 1: Open the Network tab
There are three easy ways to open Chrome DevTools:
- Press F12
- Press Ctrl + Shift + I (Windows) or Cmd + Option + I (Mac)
- Right-click anywhere on the page → Inspect
Once DevTools opens, click the Network tab at the top.
Tip: If you see nothing, reload the page (Ctrl + R) while the Network tab is open. DevTools only records requests while it's open.
Step 2: Watch the requests roll in
As the page loads, you'll see a long list fill up. Each row is one request. The key columns:
| Column | What it tells you |
|---|---|
| Name | The file or endpoint requested |
| Status | The result code (200 = OK, 404 = not found, 500 = server error) |
| Type | What kind of resource (document, script, fetch/xhr, img) |
| Size | How much data came back |
| Time | How long it took |
Step 3: Filter to just what matters
The full list is noisy. Use the filter bar at the top of the Network tab:
- Click Fetch/XHR to see only API calls — this is where the real data lives.
- Type a keyword in the filter box (e.g.
loginoruser) to narrow it down. - Click Img, JS, or CSS to isolate those resource types.
For most debugging, Fetch/XHR is the one you want — it hides images and styling and shows only the data your app is fetching.
Step 4: Read a single request
Click any request in the list. A panel opens with tabs:
- Headers — the URL, the request method (GET/POST), status code, and all request/response headers.
- Payload — the data your browser sent (great for checking what a form submitted).
- Response — the raw data the server sent back (often JSON).
- Preview — a nicely formatted version of the response — easiest way to read JSON.
- Timing — a breakdown of exactly where the time went.
To read an API response, click the request → Preview tab. You'll see the JSON laid out in an expandable tree.
Pro tricks
- Preserve log: check the Preserve log box to keep requests across page reloads and redirects — essential for debugging logins.
- Copy as cURL: right-click a request → Copy → Copy as cURL to replay it in your terminal or share it.
- Disable cache: check Disable cache (with DevTools open) to always fetch fresh files.
- Slow network test: use the throttling dropdown (No throttling → Slow 3G) to see how your site behaves on a slow connection.
Wrapping up
The Network tab is one of the most powerful tools in a developer's kit — for debugging APIs, checking why a page is slow, or just understanding how a site works under the hood. Open it up on any website and start exploring.
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