The evening gratitude dua is: 'Allahumma ma amsa bi min ni'matin aw bi ahadin min khalqika fa minka wahdaka la sharika lak, falakal-hamdu wa lakash-shukr.' Whoever says this in the evening has fulfilled the gratitude of that night for all of Allah's blessings.
اللَّهُمَّ مَا أَمْسَى بِي مِنْ نِعْمَةٍ أَوْ بِأَحَدٍ مِنْ خَلْقِكَ فَمِنْكَ وَحْدَكَ لَا شَرِيكَ لَكَ، فَلَكَ الْحَمْدُ وَلَكَ الشُّكْرُ
Allahumma ma amsa bi min ni'matin aw bi ahadin min khalqika fa minka wahdaka la sharika lak, falakal-hamdu wa lakash-shukr.
Meaning: O Allah, whatever blessing I or any of Your creation have come upon this evening is from You alone, without partner. So for You is all praise and to You is all gratitude.
Source: Sunan Abu Dawud #5073This is the evening version of the morning gratitude dua. The Prophet (peace be upon him) taught that whoever says this in the evening has fulfilled the gratitude owed for that entire night. It reminds the believer to reflect on all blessings received throughout the day and attribute them to Allah alone.
اللَّهُمَّ مَا أَمْسَى بِي مِنْ نِعْمَةٍ أَوْ بِأَحَدٍ مِنْ خَلْقِكَ فَمِنْكَ وَحْدَكَ لَا شَرِيكَ لَكَ، فَلَكَ الْحَمْدُ وَلَكَ الشُّكْرُ
The Messenger of Allah (peace be upon him) said: 'Whoever says in the morning: Allahumma ma asbaha bi min ni'matin... he has fulfilled the gratitude of that day. And whoever says it in the evening (replacing asbaha with amsa), he has fulfilled the gratitude of that night.'