Praise be to Allah.
We have not come across any of these apps.
However, in general, what we may be certain of is that no one knows the unseen except Allah, so no one can know that so and so will keep your secrets, or be sincere to you, or bring you happiness, unless he has stayed close to him and watched how he is for a while, or that is done by telling you some stories about him which indicate that. But even then, it remains a matter of speculation.
If you say, for example: I feel happy when I see this friend, and I feel sad when he is not here,
this means that he brings you happiness!
If you say: So and so feels sad when I feel sad, and stands with me at times of hardship, and helps me in times of difficulty, and does not fall short in advising me and guiding me,
then it may be said to you that he is sincere towards you, based on outward appearances, and Allah knows best what is in people’s hearts.
But as you see, this is a kind of foolishness and stating the obvious, or speculation and sorcery.
Based on that, one of the two following scenarios must apply to these apps:
The first scenario: these apps tell you about the character of your friend based on the data that you tell it. Anyone can do that, but the fact remains that this verdict is given on the basis of outward appearances, and that made not be how things really are. How many deceivers have appeared outwardly to be sincere and trustworthy friends, and vice versa.
How many people have treated their friends kindly for a lifetime then his friend blames him for a single sin or mistake that hurt him, and he no longer remembers anything else about him; he blames him for that and forgets his previous kind treatment.
The second scenario: these apps do not rely on the data you tell them; rather it is sufficient to mention the name of the friend, or his date of birth, or show his picture, or his profile picture, then the app tells you about his characteristics. All of this comes under the heading of fortune telling and claiming to have knowledge of the unseen, and it is not permissible to use these apps or to believe them, because of the hadith of Safiyyah bint Abi ‘Ubayd, from one of the wives of the Prophet (blessings and peace of Allah be upon him), that the Prophet (blessings and peace of Allah be upon him) said: “Whoever goes to a fortune teller and asks him about anything, no prayer will be accepted from him for forty days.” Narrated by Muslim (2230).
It was narrated from Abu Hurayrah that the Prophet (blessings and peace of Allah be upon him) said: “Whoever goes to a fortune teller or soothsayer, and believes what he says, has disbelieved in what was revealed to Muhammad.” Narrated by at-Tirmidhi (135), Abu Dawood (3904) and Ibn Maajah (693); classed as saheeh by al-Albaani in Saheeh at-Tirmidhi.
In the answer to question no. 121011, we have previously explained the difference between personality tests based on scientific principles and those which are a type of fortune telling; please refer to this question.
And Allah knows best.