Hey everyone,
I noticed a lot of players are still looking for a working BigDebuffs addon for 3.3.5a, but most versions out there are marked as outdated. So I decided to share a fully working version that I've tested myself.

However, this version needs the ClassicAPI addon to function properly — it won’t work on its own.

Step 1: Download ClassicAPI
Grab it from here:
ClassicAPI
Once downloaded:
- Extract the ZIP file
- Open the extracted folder
- Inside, you’ll find a folder named !!!ClassicAPI .
Copy that folder to:
your WoW folder => Interface => AddOns
Step 2: Download BigDebuffs 3.3.5a:
Download BigDebuffs 3.3.5a
- Extract it
- Open the extracted folder
- Copy the BigDebuffs folder into your Interface => AddOns directory
That’s it! Launch the game and it should work perfectly.
Credit : Tsoukie
Source & full guide: BigDebuffs-3.3.5 By Tsoukie