The Fly JS runtime has been deprecated

This product has been replaced by the Fly container runtime.

Edge Applications

Fly Edge Applications are JavaScript applications that run at "the edge", which is just a spiffy, investory compliant way to say "on servers close to your users".

These are full applications, deployed globally. You can build proxy based middleware to augment your existing apps, or integrate with your customers' applications. Or, build full featured apps entirely from scratch.

Open Source

Edge Applications are open source. We do our development in public on superfly/fly. This is our Apache Licensed core software, and exactly what you get when you npm install @fly/fly. It can be used for local testing, or even production deployments (with a little extra elbow grease).

Our commercial service is a global hosting, distributed caching services, and associated infrastructure. If you like what we do and want to fund useful OSS development, deploying on our platform is a nice way to do that!

The JavaScript Environment

The Fly JavaScript runtime is built on top of v8, and designed to service requests with very little additional latency. There are no long boot times or warmup times, we receive an HTTP request and hand it off to your JavaScript in < 1 ms. The base API is a subset of what's available in modern browsers, with some Fly specific APIs for in memory caching and other proxy specific functionality.

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Datacenter Locations

We have 16 datacenters across the world, with more coming in 2019.


Application pricing is metered. We track compute time, cache storage, bandwidth use and paid additions, then bill you for the total at the beginning of each month.

Each new account comes with a feature-complete free trial.

Pricing details →
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