Where are my Fastly Settings applied in VCL?

Here’s a general overview of where in your VCL you can see your Fastly settings applied:

vcl_recv receives the request:

• Default Host is set.
• Backends are set. This also where rules for routing requests to specific backends are applied.
• Shielding is set, if enabled.
• Request Setting are set to allow you to force an action - such as look-up or pass - on a request.
• Request Headers are applied to the request object.
• Request Conditions capture url requests for special settings and routes to vcl_error - for example, HTTP Redirects, Custom (synthetic) Responses, URL rewrite/redirect.

vcl_error handles errors and custom redirects or responses:

• Force SSL request settings, HTTP redirects at the edge, and Custom (synthetic) responses are routed here from vcl_recv. May make changes to the object’s status code, response, location, content-type, and/or content. Then routes the object to vcl_deliver.

vcl_fetch runs after fetching the object from your origin. Settings applied here will affect how the object is cached:

• Default TTL is applied to the object.
• Cache-Settings that set cache rules based on backend responses or set Force PASS on an object.
• Cache Headers are set to store information on the cached object.
• Stale-while-revalidate and Stale-with-Error rules are applied.
• Automatic GZIPing rules are applied.

vcl_deliver executes right before the response object is delivered to the client:

• Response headers are set to return a header back to the client, without caching the header itself.
• Logging Logic is applied.