[00:02] of senior engineers can't explain in an interview. You and a friend are editing the same document. You both type in the exact same spot at the exact same time. What happens next? Every collaborative application answers this differently.
[00:16] Let me show you three main strategies. The first is a naive last write wins. If two people edit the same thing, whoever saves last overwrites the other. It's really simple, but you lose data. That's why most production systems don't use
[00:31] it. The next is operational transform. This is what Google Docs uses. Instead of overriding, it takes every edit and adjusts it based on what everyone else did. So, if your friend inserts a character before your edit, your edit
[00:45] automatically shifts over to the right place. The last is CRDTs. This is similar to what Figma uses. Instead of a central server transforming every edit like operational transform, each user's device figures it out on its own. Every
[01:00] character gets an ID and a position baked in from the moment it's created. So, no matter what order edits arrive, even if you were offline for an hour, everything merges to the same result automatically. If you want to go deep on
[01:14] OT and CRDTs, check out our full video for more.