How to ensure the security of user data?

Question

Java

Hello dear habrchane.
Recently completed my first application for Android.
The application is designed to monitor free-lance.ru, i.e. you log in to your freelance account through the application, and the application informs you about incoming projects and messages on the service using the specified filter.
Apart from the service free-lance.ru and Google Analytics, the application no longer communicates with any servers.
After I posted the application, I wrote about it on a freelance blog, and immediately received information in a personal message that people were afraid to enter their data into the application, and asked to post the source code. It's clear that I can't post the source codes, because hundreds of clones will come out tomorrow.
When creating the application, I expected a similar reaction, but I developed the application initially for myself.
The application completely copies the functionality of the FreeTray desktop application developed by free-lance.ru
In principle, as a guarantee of security, I relied on the rating of my freelance account, which cannot be restored if the account is blocked, since user reviews were canceled on the service. And if it turns out that my application is stealing data, then my account will be blocked, and I will lose a piece of bread.
Good people, how can you guarantee people's safety without uploading the source code?
Thank you all in advance for your replies!

Answer 1

As far as I know, free-lance.ru doesn't have an official api? If so, then there is no way you can guarantee people's safety. Only words.

Answer 2

Tell the same thing in the description of the program, while giving a link to your account.

Answer 3

An attempt to contact the freelance administration did not lead to anything. I offered them the source code for consideration, so that they would later express their opinion, and received the following answer:
Никита, к сожалению, мы не будем тестировать ваш программный продукт и писать на него отзывы. Каждый кто использует программу - использует ее на свой страх и риск. В свою очередь хотим предупредить, что если программа будет создавать нагрузку на сайт - мы вынуждены будем ее заблокировать.С уважением, Михаил ЦветиковРуководитель административного отдела Free-lance.ru