The answer is no.
Team Agar.io has created a video with information about the reason this is not allowed:
Things that go against our terms and conditions:
- Extensions are hacks - Not allowed
- Hacking the skin editor is a hack - Not allowed
- Uploading and using Agar.io Copyrighted skins - It is theft - Not allowed
- Uploading and using Others Copyrighted images - It is theft - Not allowed
- Selling accounts - Not allowed
- Stealing accounts - Not allowed
- Bots - Not allowed
We hope this is clear.
Please refrain from indulging in any suspicious behavior. Respect the game and those that play it.
Most importantly, have fun 😊