The Messenger of Allah ﷺ said the takbir seven times in the first rakah and five times in the second during the two Eid prayers.
حدثنا أبو مسعود محمد بن عبد الله بن عبيد بن عقيل حدثنا محمد بن خالد بن عثمة
أن رسول الله ﷺ كبر في العيدين سبعا في الأولى وخمسا في الآخرة
Sourced from Tirmidhi, Jumuah, chapter on what has been narrated concerning the takbir in the two Eid prayers, no. 536, from the hadith of Kathir, in this wording, and he said it is hasan. See no. 165 for its defect. The hadith has hasan supporting narrations, see the following and preceding hadith.