Spinach — Food safety facts
Safe to share · Cats · full breakdown on the linked food page
Small amounts are fine; large amounts of oxalates can be hard on the kidneys over time.
Short answer
Yes, a small amount of plain cooked spinach shared occasionally is safe for cats. Spinach contains oxalates, which in very large, regular quantities could contribute to kidney stress over the long term, but an occasional bite as a treat is not a concern. Ensure it's plain, with no added salt, butter, garlic, or onions. If your cat enjoys it and has no digestive upset afterward, it can be a fine occasional addition.