The دعاء at iftar is: 'Dhahaba az-zama'u wabtallatil-'uruqu wa thabatal-ajru insha'Allah' — The thirst has gone, the veins have been moistened, and the reward is confirmed, if Allah wills. This is the authentic سنة دعاء for breaking the fast.
ذَهَبَ الظَّمَأُ وَابْتَلَّتِ الْعُرُوقُ وَثَبَتَ الْأَجْرُ إِنْ شَاءَ اللَّهُ
Dhahaba az-zama'u wabtallatil-'uruqu wa thabatal-ajru insha'Allah.
Meaning: The thirst has gone, the veins have been moistened, and the reward is confirmed, if Allah wills.
Source: Sunan Abu Dawud #2357النبي (صلى الله عليه وسلم) said: 'There are three whose دعاء is not rejected: the fasting person until he breaks his fast, the just ruler, and the الدعاء of the oppressed' (سنن الترمذي 3598). The moment of iftar is thus one of the most powerful times for دعاء, and the fasting person should prepare their most important الأدعية for this moment.
ذَهَبَ الظَّمَأُ وَابْتَلَّتِ الْعُرُوقُ وَثَبَتَ الْأَجْرُ إِنْ شَاءَ اللَّهُ
When the Prophet (peace be upon him) broke his fast, he would say: 'Dhahaba az-zama'u wabtallatil-'uruqu wa thabatal-ajru insha'Allah.'