Learn to build on the Fastly platform

Fastly offers two types of edge service: highly performant and configurable services powered by Fastly VCL, and next generation Wasm-powered Compute@Edge services currently in private beta:


Write your code in Fastly's proprietary VCL language and we will compile and run it for you at the edge.


Compile your own Rust code into WebAssembly and Compute@Edge will run your binaries at the edge.

Whichever service type you choose, many concepts are common. And while not all Fastly features are supported by Compute@Edge yet, many more will be added in the coming months as we move towards general availability.

Domains and backends

Domains are hostnames that point to your services on Fastly. Backends are hostnames that point to the origin servers hosting your application. Healthchecks are pre-configured requests that Fastly POPs should make, to your backends, to confirm that they are ready to receive end user traffic.

Illustration of domains and backends

Domains, backends, and healthchecks can be configured in multiple ways:

Using the fastly CLIfastly domain createfastly backend createfastly healthcheck create
Using the APICreate domain endpointCreate backend endpointCreate healthcheck endpoint
Using VCLCannot be managed in VCLbackend { ... } declarationPart of a backend { ... } declaration
Using the web interfaceSee Managing domainsSee Managing originsSee Working with health checks

Routing and caching

Fastly respects the instructions you provide via HTTP headers such as Cache-Control. But you can also exert much finer-grained control over the way we load and cache your resources.

Content transformation

As well as serving content loaded from your origin, Fastly can also manipulate that content in useful ways, or even generate content from scratch without loading anything from your origin.

Edge state and data stores

Our edge state products allow reads at the edge and updates via the API.


Learn how to configure Fastly to meet your security needs.

Logging, debugging and diagnostics

Observability and debugging tools to help fix problems, test and monitor your Fastly services.