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 buildx-0-t: timings of all the components in Layer0 critical path that served your requestx-0-request-id: the unique ID of the request on Layer0 infrastructurex-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: <id>=<time>[,<id2>=<time2>...]
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 =
o - Level 2 Shield POP =
s - Custom Layer0 Proxy =
p - JavaScript Compute Workers =
w
All times are in milliseconds.
| Name | Description |
|---|---|
| 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 1, if not your account is under significant pressure and you should consider upgrading it. |
| pf | The time spent waiting for a response from the JavaScript worker |
| wm | The amount of memory used in MB by the JavaScript worker to process the request |
| wt | The JavaScript worker execution time |
| wr | The time spent matching routes in the JavaScript worker |
| wa | The time spent transforming the request in JavaScript worker. Will only be provided if the request was transformed. |
| wp | The time spent waiting for your application (Next, Nuxt, Sapper, Angular, etc...) or origin to respond |
| wz | The time spent transforming the response in JavaScript worker. Will only be provided if the response was transformed. |
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 cacheHIT-L2- The page was served from the shield cacheMISS- 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 requestx-0-components: versions of different components in Layer0 critical path that serviced your request