About App2App SDK

Last updated: August 1, 2026  |  Guide version: 1.0.8

About

Allows making payments with amount and registration information sent to the SoftPOS application without adding any payment library to your application, via App2App integration.

Data exchange between applications is provided by creating a channel with a Messenger Service.

Importing the SDK

  1. Put the App2AppSDK library (.aar) file into the folder where app dependencies are added (generally the 'libs' folder)
  2. Add the library to gradle dependencies as 'implementation'
  3. Initialize the App2App SDK to start using it

Gradle example

allprojects {
  repositories {
    flatDir {
      dirs 'libs'
    }
  }
}

dependencies {
  implementation(name:'App2App-SDK-v1.0.0-Debug', ext:'aar')
}

Supported operations

Operation SDK method Description
Register getOnlyRegister Registers the terminal without a payment.
Payment getPayment Starts a Sale, Refund, Void or Tokenization transaction.
Last Transaction Query getLastTxn Returns the last transaction from the backend.
Transaction List gotoList Opens the refund, void or history list in the payment app.
Manual Settlement gotoManuelSettlement Starts settlement from the sales app.
Unregister unRegister Deactivates the current terminal.

Payment app response codes

The payment app returns these codes in the a2aCode field of its responses.

Code Name Description
1002 Internal Error Unexpected error in app
1003 Register error Error encountered during registration. Backend message can be added to the continuation. e.g. "Register error : Server Error please contact with your administrator"
1004 unregister ERROR, please try again If registerParameter is sent, softpos app unregisters then registers. Message during unregistration.
1005 Initialize error If an error is received during initialize, this code and message are returned. Backend message can be added to the continuation.
1006 JsonParse error If the message from the merchant application is not suitable for the json structure, this message and code is returned.
1007 Amount cannot be alphanumeric characters, null, 0 Relates to the submitted amount.
1008 transaction size = 0 If there is no transaction and you want to see the last transaction (appLastTxn), this message returns.
1009 Registration Successful —
1010 SoftposApp Stopped —
1011 The application was closed because application was opened standalone In app2app there is a standalone mode feature which allows the application to get payment independent from the merchant app. If this feature is disabled and the payment app is started, this error is returned.
1012 Connection Error Returned when there is a problem with the connection
1013 Manual Settlement Successful Returned when the manual settlement process is completed
1014 Registration Needed Returned if required registration does not exist
1015 No action SoftposApp StandBy in background
1016 No action Transaction Canceled by User
1017 Unregistration Successful Returned when the terminal has been unregistered successfully.

Version history

Current version Status Valid date Prepared by
1.0.8 Valid August 1, 2026 Fatih Aksu
All versions (8)
Version Status Date Prepared by Description
1.0.8 Valid August 1, 2026 Fatih Aksu Unregister Function added
1.0.7 Valid December 9, 2025 Manzura Jorayeva Refusal Code 96 added
1.0.6 Valid July 3, 2025 Zafer Topcu Receipt Options and Receipt Button Displayed added
1.0.5 Valid October 11, 2024 Zafer Topcu Timeout feature and Auto Receipt Sharing feature added
1.0.4 Valid August 27, 2024 Ismail OZKAN App2app workingMode development has been added
1.0.3 Valid June 20, 2024 Samed ARSLAN App2AppService API's parameters are updated
1.0.2 Invalid May 29, 2024 Samed ARSLAN SDK Dependency Import Guide added
1.0.1 Invalid January 10, 2024 Samed ARSLAN Initial Documentation

See also