Banksalad appears in Apple Stores

The Banksalad iOS team received a request to develop a demo app for visitors to Apple Retail Store, and completed development within a short period of about 2 weeks, resulting in the app being displayed at Apple stores nationwide.

Demo App Development Constraints and Solution Strategy

Apple presented conditions such as removing login and sign-up procedures, offline operation, and no asset synchronization for the demo app. Accordingly, the team built personas based on actual user groups (students, parents, investors, etc.) and adopted an approach using JSON data stored within the client, without server communication.

Leveraging Weak Dependencies Based on Protocol

Banksalad's existing iOS architecture separated Service, View Model, and Repository each into Protocols and implementations. In the demo app, instead of the existing Repository implementation, a new implementation that decodes data within the client was applied, configuring the demo environment with minimal code changes. This was similar to the Mock-Implement approach used when writing test code, which increased development speed.

Resolving the Time Synchronization Issue of Static Data

When using static JSON data, an issue arose where transaction history dates were fixed, causing the current month's household ledger tab to appear empty. To resolve this, the team modified the Date Parser logic to add 'the difference between the current date and the final transaction submission date (2018-12-24)' to the displayed transaction dates. Thanks to this logic, even if the app is run years later, the transaction history appears up to date.

Results and Implications

This demo app, developed quickly including 3 days of the Chuseok holiday, was displayed at all Apple retail stores in Korea around November. The keys to success were the Protocol-based weak dependency structure, code changes that minimized disruption to user experience, and the team members' collaboration and persistence. Based on this technical achievement, Banksalad is currently hiring new talent, including Junior iOS Engineers.