He who does not recite Fatihat al-Kitab is not credited with having observed the prayer.  

النَّبِيَّ ﷺ لاَ صَلاَةَ لِمَنْ لَمْ يَقْرَأْ بِفَاتِحَةِ الْكِتَابِ  

The Messenger of Allah ﷺ commanded me to announce that prayer is not valid but with the recitation of Fatihat al-kitab and something more.  

أَمَرَنِي رَسُولُ اللَّهِ ﷺ أَنْ أُنَادِيَ أَنَّهُ لاَ صَلاَةَ إِلاَّ بِقِرَاءَةِ فَاتِحَةِ الْكِتَابِ فَمَا زَادَ  

The Prophet ﷺ said: "There is no Salah for one who does not recite Fatihatil-Kitab." (Using translation from Nasāʾī 910)  

النَّبِيَّ ﷺ قَالَ «لَا صَلَاةَ لِمَنْ لَا يَقْرَأُ بِفَاتِحَةِ الْكِتَابِ»  

Go out and announce in medina that prayer is not valid but the recitation of the Qur’an even though it might be fatihat al-kitab and something more. (Using translation from Abū Dāʾūd 819)   

قَالَ رَسُولُ اللَّهِ ﷺ «اخْرُجْ فَنَادِ فِي النَّاسِ أَنْ لَا صَلَاةَ إِلَّا بِقِرَاءَةِ فَاتِحَةِ الْكِتَابِ فَمَا زَادَ»  

The Messenger of Allah ﷺ commanded me to announce that prayer is not valid but with the recitation of Fatihat al-kitab and something more. (Using translation from Abū Dāʾūd 820)   

أَمَرَنِي رَسُولُ اللهِ ﷺ أَنْ أُنَادِيَ لَا صَلَاةَ إِلَّا بِقِرَاءَةِ فَاتِحَةِ الْكِتَابِ فَمَا زَادَ  

"لَا صَلاَةَ إِلَّا بِقِرَاءَةِ فَاتِحَةِ الْكِتَابِ فمَا زاد".  

"The Ṣalāh is not ˹valid˺ for the one who does not recite from the Opening of the Book (Sūrat al-Fātiḥah)."  

«لَا صَلاَةَ لِمَنْ لَمْ يَقْرَأ بِفَاتِحَةِ الْكِتَابِ۔»  

"لَا صَلاَةَ إِلَّا بِفَاتِحَةِ الْكِتَالْ وآيَتَيْنِ مِنَ الْقُرآنِ مَعهَا".  

"لَا صَلاَةَ إِلَّا بِقُرْآنٍ: بِفَاتِحَةِ الْكِتَابِ فَمَا زادَ".