Compute
Last updated 2025-03-21
Fastly’s Compute platform, formerly known as Compute@Edge, helps you compile your custom code to WebAssembly and runs it at the Fastly edge using the WebAssembly System Interface for each compute request. Per-request isolation and lightweight sandboxing create an environment focused on performance and security.
IMPORTANT
This feature is not permitted for use in cryptocurrency mining.
Serverless isolation technology
Compute runs WebAssembly (Wasm). When a Compute request is received by Fastly, an instance is created and the serverless function is run, allowing developers to apply custom business logic on demand.
Global deployment
Deploying to a Compute service leverages Fastly’s software-defined network and globally distributed points of presence. A single deploy action makes customer logic available across the Fastly network.
Available programming languages
By running Wasm on the Fastly network, Compute creates a serverless environment suitable for multiple programming languages. Fastly collaborates with the Bytecode Alliance and other open source communities to actively grow the number of supported languages. Support level per language varies. Resources per language are available in our documentation.
Logging endpoint compatibility
Compute supports sending user-specified logs to a variety of logging endpoints. These connections can be created and managed via manage.fastly.com and by using a supported language.
Continuous integration and deployment
Deployment to the Compute platform can be accomplished via the Fastly control panel, the Fastly API, and via Fastly’s Terraform provider plugin. The Fastly CLI also provides a local toolchain with features for creating, debugging, and deploying to Wasm services, including Log Tailing and Local Testing.
NOTE
Some Compute features available through the Fastly CLI are disabled by default. To learn more about them, contact your account manager or email sales@fastly.com for details.
Compute features
As part of our Compute product offering, Fastly provides you access to the following collection of features.
Cache APIs
Cache APIs enable developers to build apps on Compute using Fastly's global cache network.
Dynamic Backends
Dynamic Backends extends the Fastly API and allows you to decide which origin to connect to at runtime instead of having to define it ahead of time in your configuration. With Dynamic Backends, you can dynamically adjust your origin definitions, dispatch to new hosts based on computed values, and connect to a wider variety of origin servers.
Edge Data Storage
Use one of our Edge Data Storage solutions to store data at the edge as key-value pairs in versionless containers.
Log Tailing
Log Tailing allows you to stream custom log messages from your Compute application so you can respond quickly when debugging the application without setting up a third-party logging tool.
Local Testing
Local Testing allows you to run your work-in-progress applications locally on your laptop, server, or CI system, so you can test your Compute applications without hosting them on public staging or production environments. Local environments support a subset of Compute features.
Resource limits
Fastly services and individual instances are allowed a specific range of resources per service and per execution as described in our Compute resource limits. These limits change based on whether or not you've purchased one of our packaged offerings or you're using a trial account.
Keep these limitations and constraints in mind especially when testing and debugging on Compute, when sending Fastly logs to third party logging providers, and when using Log Tailing.
Billing
NOTE
Billing limits for this product may be different if you've purchased a packaged offering or are using a product or feature trial.
Fastly charges for Compute based on the total number of compute requests you make plus their compute duration and CPU time. Each compute request uses the Fastly delivery architecture and the associated Compute charges apply in addition to any already applicable delivery charges.
Compute requests. Compute requests represent a count of the number of times you invoke a function instance. Each incoming request creates one function instance.
Compute duration. Compute duration represents the total memory allocation over time required to process a compute request. We measure memory allocation in GB-seconds and calculate it based on the time it takes for a function instance to execute, multiplied by the memory allocated to that function. We measure function instance time in wall clock time from the start of a function to its completion or termination, rounded up to the nearest 50ms. The minimum function size for billing purposes is 128MB, though actual memory allocation may differ.
CPU time. CPU time represents the sum of the total time spent by the CPU running your code.
For more details about this product, including pricing information and help with purchasing it, contact your account manager or email sales@fastly.com.
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