This guide covers the headers that Layer0 injects into responses making them visible to your client code.
x-0-version: version fingerprint that includes Layer0 version number, site build number and UTC timestamp of the build
x-0-t: timings of all the components in Layer0 critical path that served your request
x-0-request-id: the unique ID of the request on Layer0 infrastructure
x-0-hit-request-id: the unique ID of the request whose cached response is being returned (not present if cache miss)
x-0-caching-status: indicates why a response was or was not cached. See Caching.
x-0-surrogate-key: a space separated list of secondary cache keys used for cache clearing
The format is
x-0-t is an order list of timings: values are prepended at response time. Thus reading them left to right goes from the outermost edge component to the innermost cloud component that handled the request.
The components are:
- Level 1 Edge POP =
- Level 2 Shield POP =
- Custom Layer0 Proxy =
All times are in milliseconds.
|ot||The total time spent processing the request|
|or||The time spent matching routes at the edge POP|
|of||The time spent fetching the response at the edge POP, either from the shield POP or from the serverless backend or origin|
|oc||The caching status for the edge POP|
|ow||The free memory in bytes on the edge POP after processing the request|
|oq||The time spent at the edge POP in fetch queue during the request coalescing|
|st||The time spent processing the request at the shield POP|
|sr||The time spent matching routes at the shield POP|
|sf||The time spent waiting for a response from the serverless backend or origin, including request queueing|
|sc||The caching status for the shield POP|
|sw||The free memory in bytes on the shield POP after processing the request|
|sq||The time spent at the shield POP in fetch queue during the request coalescing|
|bf||The time spent waiting for a response from the serverless backend or origin, including request queueing|
|pc||The number of times the request was scheduled to execute. If it's present it is normally |
|wp||The time spent waiting for your application (Next, Nuxt, Sapper, Angular, etc...) or origin to respond|
Layer0 adds the following values to the standard server-timing response header:
- layer0-cache: desc=
value- value will be one of:
HIT-L1- The page was served from the edge cache
HIT-L2- The page was served from the shield cache
MISS- The page could not be served from the cache
- country: desc=
country_code- where country_code is the two letter code of the country from which the request was sent.
- xrj: desc=
route- where route is the matched route serialized as JSON.
The following headers are used internally by Layer0 staff to troubleshoot issues with requests.
x-0-status: statuses of different components in Layer0 critical path that serviced your request
x-0-components: versions of different components in Layer0 critical path that serviced your request