Question 1

High load

Accepted Answer

As the application's primary mission is to provide users with the ability to send customized greeting cards and gift certificates, peak usability occurs during the most popular celebration days, such as Christmas and Mother’s Day. The heightened demand during these high-traffic periods led to an increase in load that caused performance bottlenecks. As an outcome, this provoked significant slowdowns in the system’s functionality Implemented solution To resolve the issue, we took the following actions: * Firstly, the database management was performed by optimizing the complex queries. * Indexing and horizontal scaling of the database were implemented to handle large number of queries. Our developers integrated the database-level caching and utilized Redis to lower the load. * Subsequently, Sidekiq and Redis were applied to perform long and resource-intensive operations in the background (Background Jobs), which provided a quick response for users. * The third step was read/write database partitioning through Ruby on Rails. The separation of the databases for the presented functions aimed at balancing the load. * We performed load testing and, by simulating the high pressure, identified and overcame weaknesses in the system. This set of actions enabled us to maintain the correct functionality of all three of Givingli’s platforms during the peak dates.

Question 2

Multi-platform support

Accepted Answer

The Givingli ecosystem consists of three platforms: web software, an iOS app, and an Android application, which elucidated the challenges of multi-platform software maintenance, as it required a sync in feature delivery and seamless interoperability between the platforms. Implemented solution Our developers implemented the API versioning approach, enabling the creation of a consistent experience for users of all platforms. It also enabled the independent implementation of the updates by the platforms without any threat to system integrity as a whole. * API versioning was crucial to maintain backward compatibility, as customers could still use older versions while new features were added. * The presented solution was pivotal as it enabled the implementation of the new digital elements by preserving integrity without breaking the existing logic of the platform. * Up-to-date automatic documentation optimized developers' interaction with the API. * Our final solution was checking and testing that various environments worked properly. This was important as the versatility of the platform required proper coordination. This was the reason why we applied integration testing and QA manual testing.

Question 3

App responsiveness & high level of user experience

Accepted Answer

The client wanted to focus the content of their greeting card app development on being more diversified and delivered through unique and aesthetic design elements. From a technical perspective, this brought the challenge of managing the rendering of dynamic content while supporting high-level application performance, user experience, and app responsiveness. Implemented solution We used WebSockets to promote and maintain the real-time functionality of the live chat and notification systems so that the clients could enjoy interactivity across three platforms. Standard libraries for animations and design did not consistently provide the required optimization level to support high-quality of user experience and app responsiveness. Thus, in order to achieve the best user experience, Agilie crafted a set of custom solutions to focus on enhancing the application response time and streamlining operations to grant seamless performance. The following is a couple of illustrative examples. Custom card builder We crafted a custom card builder, a tool utilized for creating and designing personalized gift cards with text, video, and audio components to make individualized greetings. Initially, the Konva.js library was applied to cover the aforementioned functionalities. However, its lack of optimization for multi-platform support made it challenging to maintain the functionality of those design patterns, as by that time, Givingli had an iOS app and Web platform. The challenge above made us transition to the HTML Editable Component as it provided the opportunity to embed the HTML tags directly to the input field. This solution streamlined the flexibility in customizing non-trivial, individualized designs, videos, and audio materials, by optimizing user experience and application responsiveness. Content rendering While elaborating on Givingli’s custom calendar, Agilie faced the dilemma of content saturation. The calendar displayed events in a one-month range but included two additional rows above and below the visible month. The upper row kept data for the preceding months, while the lower reflected content elements for the upcoming months. We encountered a substantial rise in the rendered content elements when scrolling through multiple months, mainly for a six-month range. This led to performance bottlenecks, represented by the performance lag and delayed responsiveness in the calendar’s functionality. As it handled the large dataset that was rendered inside the scrollable container, our team worked on the virtual scroll approach. Virtual scroll rendered only the visible elements in the viewport. This optimization effectively reduced the number of DOM elements with optimized memory allocation. The virtual scroll removed out-of-view DOM elements and added the new ones that emerged in the viewport. This content-loading approach eliminated lagging and improved software responsiveness and performance, which boosted user experience.

Question 4

Security challenges

Accepted Answer

The Givingli attracts multiple clients through its versatile subscription models, offering personalized gifting certificates and making the system a target for fraud requests and DDoS attacks. Implemented solution Agilie implemented the maximum number of security measures, including: * Rate limitingwas applied to restrict the number of requests a single user could make within a specific time, as this was considered a vector of potential cyberattack. * Firewall to block unauthorized access to open ports, which secured the system from intrusion. * Authentication and authorizationwere intensified to restrict access. Key encryption was used to protect sensitive data. * The implementation of New Relic was pivotal in monitoring the high request volumes and receiving alerts on suspicious user activities, including multiple attempts to log in within a short timeframe. * New Relic analyzed the system under load by enabling the detection of manipulative behavior and taking counter-measures.

Givingli

Development challenges to overcome

High load

Multi-platform support

App responsiveness & high level of user experience

Security challenges