PostHistory is an iOS app and Safari Web Extension that automatically saves a local history of posts you scroll past on x.com in Safari. Even if the timeline suddenly refreshes before you can hit Like or Bookmark, you can instantly search and find any post you viewed later — by keyword, author, images, videos, or calendar date. 100% On-Device Privacy: All history is stored locally in SQLite on your iPhone. Zero external servers, no API keys, and no login required.