The talk at FOSDEM conference in 2023 was about the process of building a library using Kotlin Multiplatform, focusing on the experience of a team that developed the Vonage Climb SDKs. The talk highlighted the challenges faced in previous attempts to achieve code sharing and the decision to use C++ as an intermediate layer. However, this approach proved to be inefficient and difficult to maintain. The team then explored other options and decided to give Kotlin Multiplatform another try. They built a prototype and, despite facing some setbacks, eventually released the SDK with two separate modules: voice and chat. The team learned the importance of keeping up with Kotlin updates and found that Kotlin Multiplatform eliminated the previous pain points and improved the development process. The talk also mentioned the use of a Mono repo, the increased ownership of features by the team, and the implementation of tests. The speaker encouraged participants to check out the Vonage Climb SDK and provided a QR code and coupon code for accessing tutorials and getting started with the SDK.