ChatStats was developed by Rodrigo Araújo as a freemium app. This app is provided through Apple's App Store at no cost and is intended for use as is.
ChatStats does not collect nor share any data from its users.
ChatStats provides value by processing WhatsApp history files, which could be received through any file sharing service or generated on the user's phone. This way, ChatStats does not need WhatsApp installed on the user's phone to work.
That file is unzipped, and parsed to count the number of messages, characters, photos, videos, voice messages, stickers, emojis and links sent, who sent them and when. Once the processing phase is finished, the app stores these counted values, the times the messages were sent and who sent them in order to generate up to 22 statistics of that group's usage. The original imported history file is thoroughly deleted from the phone. The content of the chat's messages is never stored on ChatStats database to further protect the user privacy.
After it processes the history file, ChatStats is able to generate 22 statistics about the user's group usage. As is the case with the imported data, these statistics are never collected or shared outside ChatStats. The only way they might be shared is if the user conscientiously decides to, using iOS's Share Sheet.
All of ChatStats processing happens locally inside the phone. No data is ever sent to the cloud or to any servers whatsoever. Also, ChatStats does not log usage data and has no partnership with any other service.
ChatStats provides the user with a prominent option to delete the processed data of any given group at any moment. If the user touches this delete button, every record of that group, its users and any other processed values are completely wiped from the database.
ChatStats might ask for the user permission to add photos to his/her Photo Library. As this kind of access is not needed for the app to work, it only happens if the user conscientiously decides to save one of the generated statistics' images to his photo library instead of sharing it directly from the Share Sheet.
No further permissions are ever requested, such as access to Contacts, because no further information is needed. All the information ChatStats needs to work is provided by its user through his WhatsApp chats' history files.