Fanout

Fastly Fanout is a publish-subscribe message broker operating at the Fastly edge. It provides customers with the ability to push messages via direct connections that remain open indefinitely rather than requiring clients to poll for data using short-lived HTTPS requests.

Prerequisites

To use Fanout you must purchase a paid account with a contract for Fastly's services. Once purchased, it can be enabled via API.

Limitations and considerations

Keep in mind the following limitations and considerations:

• Fanout is only available for Compute services, not Delivery services. Consider using service chaining as an alternative for Delivery services.
• Service chaining can be used with Fanout. During configuration, the service that initially handles requests from an end user (the first service) must be a Compute service and also must be the Compute service that hands off the request to Fanout.
• Fanout is not compatible with backend Directors, shielding, or the Fastly Next-Gen WAF.
• Only the Name, Address, Enable TLS, and Override Host origin server settings are supported.
• Self-signed TLS certificates are not supported. TLS certificates must be signed by a public certification authority.

Billing

We bill for Fanout based on a combination of bandwidth, connection time, and number of messages. Bandwidth is included as part of your overall delivery bandwidth rate in your monthly billing statement. Connection time is measured for each connection in usage minutes (rounded up to whole minutes) and aggregated monthly to millions of minutes. Number of messages is the sum of the total published messages received from the publish API and the total published messages sent to end users.