Do you need some help? Here you can see most common user problems and questions.



Who is behind BabelApp?

BabelApp was created by OKsystem a.s., a private and independent software company headquartered in Prague, Czech Republic. OKsystem is constantly refining BabelApp to ensure it remains at the forefront of secure data and communication transmission technology.

How does BabelApp differ from its competitors?

  • BabelApp was primarily developed for businesses and enterprises to secure their business communication using strong cryptography protocols and end to end encryption.
  • BabelApp has a very clear, transparent and understandable license- based business model.
  • BabelApp supports enterprise level features such as LDAP / AD synchronization, API integrations, server on-premise, etc.
  • A BabelApp server can be on-premise or in the cloud to meet the various needs of our clients.
  • BabelApp is developed and produced by OKsystem, a bona-fide IT company that has been on the market for almost 30 years with close to 400 employees and international partners.

What mobile devices are supported?

iPhone with iOS 7.0 and higher, Android 2.2 and higher and BlackBerry 10.0 and higher.

Is BabelApp available on Windows desktop and Mac?

Yes. BabelApp is available on Windows 7 and higher and MacOS 10.11 and higher.

What types of BabelApp are available?

BabelApp is available in 3 versions:

  • BabelApp Pro on-premise - Designed for those needing to have company communication on-site and fully under control. Can be connected to Active Directory, integrated with company applications and managed via web interface to ensure the highest level of secure and encrypted communication and data transfer.
  • BabelApp Pro cloud - Delivers BabelApp as a service. Protects communication against wiretapping and inteception whilst enabling complex and secure management in the cloud via web interface. Preserves the integrity and protection of transfered data as well as facilitating creation and management of client, partner and external collaborator accounts with ease.
  • BabelApp Lite - Non-commercial version of BabelApp. Can be downloaded and used immediately for instant private and secure communication with friends and partners. Available on Apple (iOS, Mac), Android with Windows desktop coming soon.

BabelApp Pro on-premise and cloud are commercial products, where clients pay for licenses and support in a form of a one-time installation charge and monthly (or yearly) license payment. There are no hidden fees, advertising or spam.


How strong is the encryption?

BabelApp uses end to end encryption among all the end-points, always verifying message integrity and correct sequencing. BabelApp server does not possess any of the private keys that could decrypt the messages. No data is stored on the server longer than necessary for the platform to function properly. BabelApp’s security is being continuously tested by independent 3rd party companies to ensure there are no weak spots.

Can a BabelApp server read my messages?

No. Messages are encrypted end to end, meaning that the server does not take part in the encryption process.

Are messages encrypted while stored on my device?

Yes. All messages are kept in an encrypted form in the BabelApp application.

How are my messages protected in case of a device loss or theft?

Messages are kept encrypted in the application and the device’s main encryption key is protected by your password. On the iOS platform, the application uses additional system support of data and database encryption. The mobile device must not be jailbroken or rooted. IT IS NECESSARY to use a strong password and it is RECOMMENDED to activate the remote wipe- out option.

Can anyone track my activity?

BabelApp encrypts and protects the content of your messages. The server is not hiding the fact that communication as such took place.

Is there a backdoor?

No. This is not even possible since all of the communication is end to end encrypted and not even the servers or administrators have access to the private keys used for encryption and decryption. Such keys (private keys) are generated and stored in an encrypted form on your devices only.

How is BabelApp integrated with a company’s directory services?

BabelApp servers can (if configured) import users’ accounts and phone numbers from the company’s LDAP directory (e.g., an Active Directory). This significantly simplifies BabelApp administration. BabelApp can be also configured to synchronize any changes in LDAP (creation, changes, deletion).

Using BabelApp

Why do I need to create a BabelApp Password at the very beginning?

All messages and attachments in the BabelApp application are encrypted using an encryption key, which is protected by your password. Therefore it is important to choose a strong password - as a rule of thumb we recommend using passwords that have at least 12 alphanumeric characters resistant to “dictionary attacks”.

You can enable the use of a numeric PIN or fingerprint access on your mobile devices for easier application access. Since these are weaker mechanisms, the application will ask for a strong password should the PIN or fingerprint be repeatedly unrecognized.

Verification codes do not match – what should I do?

There are 2 possibilities why this has happened.

The first and more probable reason is that you or your recipient has a new Diffie-Hellman key pair, probably due to reinstallation of the application. The new key pair will be automatically synchronized but you can always speed up the synchronization by tapping on the “synchronize” button in the server settings in your application.

A second reason could be, that somebody may be trying to perform a man-in-the-middle attack to hack into your conversation. In that case please contact your BabelApp administrator immediately.

“Next part of message has been added” - what does this mean?

In some cases long text messages (SMS) may be divided into two or more parts. If this happens, just tap the link in each message (SMS) – after you do this for all messages (regardless in which order), the divided message will be decrypted in BabelApp application.

I deleted a message but would like to read it again, is it possible?

Deleted messages are permanently deleted from one device. If you have multiple devices registered under your account, the messages are still there.

What do the Add and Block buttons mean?

Add and Block buttons were implemented to protect BabelApp users from receiving messages from unwanted contacts and appear in conversations with other users who are not currently in your BabelApp contact list.

By tapping “Add” you confirm that you wish to add the contact into your contact list and thus allow the person to send you encrypted messages via BabelApp. By tapping “Block” you place the contact into your blocklist and they will not be able to send you messages until you unblock the contact again.

How to block contacts?

Find the contact which you wish to block in your contact list and display the details. Then you can block the user. It is always possible to unblock contacts later if you go to settings – blocked users.

Why can’t I write into a conversation?

It is not possible to write into a conversation when there is one or more blocked contacts in the conversation thread. It is necessary to either unblock the contact or remove them from recipients.

Why are there exclamation marks next to some of the messages?

Should a message not be delivered to one or more of the recipients, a warning is displayed next to the message. More information can be found in the message details.

I forgot my BabelApp password - can I still see my messages?

Unfortunately no, for security reasons we do not allow password recovery as it often creates a security weak spot. Your BabelApp messages are encrypted on your device and in order to decrypt and display the messages you need to type in your password. In order to start using the application again it is necessary to reinstall the application and start over. This is part of BabelApp’s security approach.

What happens when I delete a server?

The server and all associated contacts will be deleted from your device. Conversations will remain but will be marked to let you know that the associated contact has been DELETED. If you register to the server again, the newly downloaded contacts will not synchronize with the DELETED ones (even thought it might be the same person). This is part of BabelApp’s security approach.

Why are some of my contacts displayed with their BabelApp address only and not a full name?

These contacts are unavailable or have been deleted from the server. If they become restored or available again, associated contact information will be displayed again.

What should I do if the SSL certificate in my administration console appears to be invalid?

Download a root certificate HERE and install it as a trusted certificate.

Certificate SHA-1: 6068AF9D C73F9683 5CF18618 71128521 8CBBD612

What is the meaning of the "Message expiration" term:

The message expiration specifies the amount of time, during which BabelApp server will try to deliver your message to the recipient. The timer starts counting the moment you send the message. If the message is not delivered to the recipient it will be deleted and you will be notified that the message was not delived.

What is the meaning of the "Auto-delete" term:

Function that allows you to set a time period after which the message is deleted from the recipient’s device. The timer begins to count down when the recipient reads the message.


Warning: Contact X has a new key

This is a warning displayed in a conversation when one of the recipients has changed his / her key. In most cases this is because the user has reinstalled or changed his / her device and did not transfer the old key from another device. It is advised to call that person over the phone and verify that this is the case. If not, please contact your administrator.

Warning: User has probably re-installed his / her device

This warning is displayed in conversations when a message with an invalid sequence number was sent by one of the users. This typically happens after the user has started using BabelApp on another (new) device and has transferred their old key to this device or after the user has reinstalled the BabelApp application on their device. It is recommended to call that person and verify that this is the case. If not, please contact your BabelApp server administrator immediately.

Warning: Data transfer has failed

When this error is displayed, please contact your administrator immediately, it could be due to an attack on your BabelApp server.


There are no notifications when the application is stopped.


This problem is present on Android devices from several manufacturers (e.g. Huawei and Xiaomi). It is caused by the manufacturers design to prolong battery life. You need to add BabelApp to the list of protected applications on Android devices from these manufacturers.

  • Huawei

    Settings -> Advanced Settings -> Battery Manager -> Protected Apps. You have to enable BabelApp as a protected application.

  • Xiaomi

    1) Settings -> Manage Apps' Battery Usage -> Choose Apps.
    2) Settings -> App Notifications

A problem with contacts or writing messagess

In the BabelApp application go to Settings -> Servers -> click on the server which is causing the issue and click on "reset data" at the bottom of the screen. The application will restore all contact data from the server.

Forgotten password.

You can't recover your password. You need to delete all application data and register your device again in case you forgot your password.
WARNING: You will delete all your BabelApp data by following actions (conversations, messages, drafts and attachments).


Remove/uninstall BabelApp application from your device and do the clean installation from the store.

Windows desktop

Delete BabelApp folder "BabelBE" stored in %appdata%. %appdata% are usually located in "C:\Users\current_user\AppData\Roaming\".

Mac OS X

Delete database "sms.sqlite" stored in /users/current_user/Library/Containers/cz.oksystem.babel-osx/Data/Documents/. You can type in terminal: rm -f /users/current_user/Library/Containers/cz.oksystem.babel-osx/Data/Documents/sms.sqlite and replace current_user with your account.

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