Can Browsers Detect Multiple Controllers at Once? (What I’ve Seen in Real Testing)

Testing two or more controllers online can quickly become frustrating when only one responds. Can browsers detect multiple controllers at once, or is something broken on your end? Many users struggle with inconsistent detection, mismatched inputs, or browsers recognizing only a single gamepad during testing.

“I Plugged in Two Controllers — Why Do I Only See One?”

This question comes up all the time, especially from people testing controllers for:

• Local multiplayer
• Emulators
• Couch co-op setups
• PC party games

From my own testing across browsers, operating systems, and controller types, the short answer is:

Yes, browsers can detect multiple controllers — but the behavior is not as simple or consistent as people expect.

My First Real Tests With Multiple Controllers

The first time I seriously tested multiple controllers in a browser, I expected:

• Plug in two controllers
• Both appear instantly
• Inputs tracked cleanly

What actually happened:

• Sometimes both appeared
• Sometimes only one showed up
• Sometimes the second appeared only after interaction
• Sometimes controller order changed after reload

At first, it felt buggy.

After enough testing, patterns emerged — and they’re important to understand.

How Browsers Actually Handle Multiple Controllers

Browsers don’t “manage” controllers — they expose what the operating system gives them.

Here’s the real flow:

Controllers → OS → Browser → Gamepad API → Tester

If the OS:

• Sees both controllers correctly
• Assigns them unique indexes

Then the browser can expose both.

If the OS:

• Merges them
• Prioritizes one
• Delays activation

Then the browser simply reflects that.

The Role of Controller Indexes (Why Order Changes)

Every detected controller is assigned an index number:

• Controller 0
• Controller 1
• Controller 2
• etc.

From experience:

• Indexes are assigned in order of activation, not connection
• Pressing a button on one controller first often makes it “Controller 0”
• Reloading the page can reshuffle indexes

This is why:

• Player 1 sometimes swaps controllers
• The “first” controller isn’t always the same one

This behavior is normal — and it surprises many users.

Why You Sometimes Only See One Controller

In real-world testing, the most common reasons are:

1. Second Controller Was Never Activated

Remember: each controller needs its own button press.

I’ve seen countless cases where:

• Controller A is pressed → appears
• Controller B is never touched → invisible

Until you press a button on each controller, the browser may not expose them.

2. Bluetooth Limitations

Bluetooth is convenient — but messy.

From experience:

• Some Bluetooth stacks prioritize one controller
• Some delay secondary device activation
• Some drivers combine inputs incorrectly

USB connections are far more reliable for multi-controller testing.

3. OS-Level Driver Conflicts

I’ve tested situations where:

• Two identical controllers worked
• Two different brands conflicted
• One controller silently failed to initialize

When this happens, the browser isn’t at fault — it never received both devices cleanly.

Differences I’ve Seen Between Browsers

From repeated testing:

• Chrome / Edge
  • Best multi-controller handling
  • Controllers usually appear after individual button presses
  • Index order can still change
• Firefox
  • Can detect multiple controllers
  • Occasionally drops one after reload
  • More sensitive to Bluetooth quirks
• Safari
  • Highly inconsistent
  • Sometimes detects only one controller
  • Sometimes fails with multiple devices

This matches what most advanced testers experience.

A Real Testing Scenario (What Actually Works)

When I want reliable multi-controller results, I do this:

1. Connect all controllers via USB
2. Open the tester page
3. Press a button on Controller 1
4. Press a button on Controller 2
5. Wait a second
6. Verify both appear

If I skip step 3 or 4, detection is unreliable.

Why Some Testers “Lose” a Controller After Reload

This confuses users a lot.

What’s happening:

• The page reload resets the Gamepad API state
• Controllers must re-register
• Button presses must happen again

From experience, this is expected behavior — not a bug. Browsers intentionally reset hardware access on reload.

Can Online Testers Handle More Than Two Controllers?

Yes — technically.

I’ve personally tested:

• 3 controllers
• 4 controllers

Results:

• Chrome and Edge handled them
• Index order was unpredictable
• All inputs worked once activated

However, usability drops as controller count increases — this is a UI challenge more than a technical one.

Common Mistakes Users Make (From What I See)

The biggest ones:

• Assuming connection = detection
• Not pressing buttons on each controller
• Mixing Bluetooth and USB randomly
• Expecting consistent controller order
• Reloading the page repeatedly

Once users avoid these, success rates jump dramatically.

Best Practices for Testing Multiple Controllers

Based on experience, here’s what actually works:

• Use USB if possible
• Press a button on every controller
• Don’t assume index order is permanent
• Avoid background apps that capture input
• Test in Chrome or Edge

This setup produces the fewest surprises.

Why Gampadtester.com Supports Multi-Controller Testing Properly

Gampadtester.com follows the Gamepad API exactly:

• No forced ordering
• No fake labeling
• No hidden assumptions

What you see is what the browser sees — which is exactly what you want when diagnosing real input behavior.

Test Multiple Controllers With Confidence

If you’re testing for multiplayer or hardware checks: Open Gampadtester.com
Connect each controller, press a button on each one, and verify inputs individually. That’s the correct and reliable way to do it.