Scaling Real-Time Web Updates with Server-Sent Events

Real-time updates are a core expectation of modern web applications, and in modern web development there are countless ways to achieve it. Each option has unique implications on cost, scalability, performance, and long-term flexibility. In one of our recent projects, we chose Ably as a means to deliver realtime data to all active users of a site every ten seconds. While Ably provided a reliable managed service, we noticed that our monthly bill was growing steadily as the number of active users and the amount of data we delivered increased over time.

To manage costs without compromising on functionality, we transitioned our real-time layer to a custom server hosted on DigitalOcean, implementing Server-Sent Events (SSE) as the delivery mechanism. SSE offered exactly what we needed: a simple way to stream data over persistent HTTP connections with minimal overhead. By owning the infrastructure and implementation, we eliminated third-party limits and tailored the system to our specific data model and usage patterns.

The result was a more transparent, scalable, and cost-efficient real-time architecture. Most importantly, we did not have to compromise on how much data we sent or how often we sent it. This shift highlights our dedication to delivering the right tools for every client. Managed services can be powerful accelerators in the early stages of a web-app, but a well-designed custom solution can unlock performance and flexibility that directly benefits users while cutting out recurring monthly costs.