Dua for Opening Fast - Iftar

اللَّهُمَّ اِنِّى لَكَ صُمْتُ وَبِكَ امنْتُ وَعَليْكَ تَوَكّلتُ وَ عَلى رِزْقِكَ اَفْطَرْتُ

Allahumma inni laka sumtu wa bika aamantu wa alayka tawakkaltu wa ala rizq-ika-aftartu

Pronunciation: O Allah! I fasted for You and I believe in You and I put my trust in You and I break my fast with Your sustenance

Reference: Abu Dawud: 2358