I killed the ender dragon and then when i went back to the end to look for the portal it couldn't find it anywhere
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So is there a way to get the end gateway to appear or is it not possible?

Just as a reminder, Snapshots are pre-releases of the game that can contain bugs that potentially hinder progress in a regular playthrough of the game - hence it is not recommended to use them for one.
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We're tracking this issue in MC-184482, so this ticket is being resolved and linked as a duplicate.
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