It depends on the type of preparation. u003cemu003eMarinated tomatoesu003c/emu003e are made with less vinegar and will last in the fridge for a week, tightly covered. u003cemu003ePickled tomatoesu003c/emu003e are made with brine (like these u003ca href=u0022https://www.rachelcooks.com/web-stories/pickled-red-onions/u0022u003equick pickled red onionsu003c/au003e) and will keep up to two months because the ratio of vinegar is higher. Try these u003ca href=u0022https://www.thekitchn.com/how-to-pickle-cherry-tomatoes-234385u0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003epickled cherry tomatoesu003c/au003e by Kitchn.