Build or buy: how AI changed whether your in-house realtime system is still worth it

What this post added

This post details how AI conversations have shifted the requirements for realtime infrastructure from a signaling model to a delivery model. It highlights the need for resumable streams, guaranteed ordering, and cross-device delivery, which are critical for AI agent responses. The post uses Fin's migration from their in-house Nexus system to Ably AI Transport as a case study, demonstrating the benefits of a managed solution for these new demands, including improved reliability, scale, and reduced operational costs. It also discusses the opportunity cost of maintaining in-house realtime systems and the challenges of migrating from existing infrastructure.