> ## Documentation Index
> Fetch the complete documentation index at: https://docs.extensy.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Load in Browser

> Load your downloaded extension into Chrome using Developer Mode and start testing it locally.

Before publishing your extension, load it directly into Chrome to test it. This takes under a minute using Chrome's built-in Developer Mode.

## Load the extension

**1. Download and unzip**

Click **Download ZIP** from the Extensy dashboard and save the file to your computer. Extract it into a regular folder — Chrome needs the unzipped folder, not the ZIP file itself.

**2. Open chrome://extensions**

Type `chrome://extensions` into the Chrome address bar and press Enter. You can also get here by clicking the puzzle icon in the toolbar and selecting **Manage extensions**.

**3. Enable Developer mode**

Find the **Developer mode** toggle in the top-right corner of the page and turn it on. A row of new buttons will appear at the top-left.

**4. Click Load unpacked**

Click the **Load unpacked** button that appeared after enabling Developer mode.

**5. Select your extension folder**

A file browser opens. Navigate to the unzipped folder containing your extension files (the folder that holds `manifest.json`) and select it.

**6. Verify it loaded**

Your extension should now appear as a card on the `chrome://extensions` page. If there are any errors, an **Errors** button will appear on the card — click it to see details.

## Pin the extension to your toolbar

If your extension has a popup, pin it so it's easy to access:

1. Click the **puzzle icon** in the Chrome toolbar.
2. Find your extension in the dropdown list.
3. Click the **pin icon** next to it.

Your extension's icon will now appear directly in the toolbar.

## Test your extension

Once loaded, verify it works as expected:

* **Popup-based extensions** — Click the toolbar icon to open the popup and interact with it.
* **Content script extensions** — Open a tab that matches your extension's target site (e.g., `wikipedia.org`) and look for the injected UI or behavior.
* **Background event extensions** — Trigger the event your extension listens for (e.g., opening a new tab, installing the extension) and check the result.

> [!TIP]
>
> If you don't see anything on the page, try refreshing the tab. Content scripts don't inject into tabs that were already open when the extension was loaded.

## Reload after editing

When you make changes to the extension's files, you don't need to remove and re-add it. Instead:

1. Save your file changes in your code editor.
2. Go to `chrome://extensions`.
3. Click the **reload icon (↺)** on your extension's card.
4. Refresh the tab you're testing on.

> [!NOTE]
>
> Chrome does not hot-reload extensions. You must click the reload button on the extensions page manually after each change — the browser won't pick up file edits automatically.

## Troubleshoot load errors

If the extension fails to load or behaves unexpectedly:

* Click the **Errors** button on the extension card in `chrome://extensions` for a detailed breakdown of which file and line caused the issue.
* Open Chrome DevTools (`F12` or right-click → Inspect) on the page you're testing. Check the **Console** tab for JavaScript errors from content scripts.
* For popup errors, right-click the extension icon in the toolbar and select **Inspect popup** to open DevTools scoped to the popup.

## Other Chromium browsers

These same steps work in any Chromium-based browser. Look for the equivalent extensions management page in:

* **Brave** — `brave://extensions`
* **Microsoft Edge** — `edge://extensions`
* **Opera** — `opera://extensions`
* **Vivaldi** — `vivaldi://extensions`

Enable Developer mode and use **Load unpacked** the same way.

> **[Edit & iterate](https://docs.extensy.dev/using-extensy/editing-and-iterating.md)**
>
> How to modify files and reload after making changes.

> **[Download](https://docs.extensy.dev/using-extensy/downloading-your-extension.md)**
>
> What's inside your extension ZIP and what each file does.


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