The purple portal in Sell Lemons is the Void Evolution portal. It unlocks late-game evolution and takes you to the Void area, where you can evolve for a permanent income boost and reset some progress.

What it does

  • It opens the evolution system in the game.
  • Entering it sends you to the purple Void area and the Void Altar.
  • Using evolution gives a permanent 42x income speed bonus, according to multiple guides.

How it unlocks

  • The portal appears after you reach about 500–501.2 quadrillion Investors.
  • Guides also note that it shows up behind Joe the Alien / the alien area once you hit the requirement.

In simple terms

It is basically the game’s endgame “prestige” portal: you use it to evolve, get a huge speed boost, and keep progressing faster afterward.

PortalPurposeUnlock requirement
Purple Void PortalStarts evolution / Void areaAbout 500–501.2 quadrillion Investors
Void AltarLets you actually evolveFound after entering the portal
**TL;DR:** the purple portal is the evolution portal, and it’s there to let you reset for a strong permanent boost.