If you’ve followed the history of software development, you know what comes next: middleware. And that’s exactly where Fly.io, founded by Kurt Mackey, comes in. Full disclosure: Mackey is’ former technology director. And his Fly.io platform is a “global load balancer” in that it puts gateways for programming interfaces in data centers around the world. Much like how Cloudflare uses the “Anycast” feature of the Border Gateway Protocol to provide a content delivery network, Fly.io uses Anycast to leverage routing of application requests to the nearest gateway. The gateway connects back to the back-end of the application through an encrypted SSH tunnel.
But the middleware running on the gateway can also be used to handle a lot of the work that previously would have required multiple requests from the Web browser or app client. Fly.io provides a number of middleware components that can handle many of the processing tasks currently handled either by the back-end application or script in the browser. Developers can wire together middleware components through a Web-based tool before connecting them to an agent on their application server. Multiple back-end services can be put behind a single DNS address—for example, Fly.io’s own site uses Github Pages as a back-end service to provide its documentation.
Fly.io has something else in common with Cloudflare—getting started with the service is free, as are the first 50,000 application requests each month. Above and beyond that, Fly,io is metered at $0.05 per 1,000 requests. Some of the pre-built middleware components have their own pricing, but any middleware marked “beta” is currently free.