Documentation
a project

API

Caddy is configured through an administration endpoint which can be accessed via HTTP using a REST API. You can configure this endpoint in your Caddy config.

Default address: localhost:2019

The latest configuration will be saved to disk after any changes (unless disabled). You can resume the last working config after a restart with caddy run --resume, which guarantees config durability in the event of a power cycle or similar.

To get started with the API, try our API tutorial or, if you only have a minute, our API quick-start guide.

POST /load

Sets Caddy's configuration, overriding any previous configuration. It blocks until the reload completes or fails. Configuration changes are lightweight, efficient, and incur zero downtime. If the new config fails for any reason, the old config is rolled back into place without downtime.

This endpoint supports different config formats using config adapters. The request's Content-Type header indicates the config format used in the request body. Usually, this should be application/json which represents Caddy's native config format. For another config format, specify the appropriate Content-Type so that the value after the forward slash / is the name of the config adapter to use. For example, when submitting a Caddyfile, use a value like text/caddyfile; or for JSON 5, use a value such as application/json5; etc.

If the new config is the same as the current one, no reload will occur. To force a reload, set Cache-Control: must-revalidate in the request headers.

Examples

Set a new active configuration:

curl -X POST "http://localhost:2019/load" \
	-H "Content-Type: application/json" \
	-d @caddy.json

Note: curl's -d flag removes newlines, so if your config format is sensitive to line breaks (e.g. the Caddyfile), use --data-binary instead:

curl -X POST "http://localhost:2019/load" \
	-H "Content-Type: text/caddyfile" \
	--data-binary @Caddyfile

POST /stop

Gracefully shuts down the server and exits the process. To only stop the running configuration without exiting the process, use DELETE /config/.

Example

Stop the process:

curl -X POST "http://localhost:2019/stop"

GET /config/[path]

Exports Caddy's current configuration at the named path. Returns a JSON body.

Examples

Export entire config and pretty-print it:

curl "http://localhost:2019/config/" | jq
{
	"apps": {
		"http": {
			"servers": {
				"myserver": {
					"listen": [
						":443"
					],
					"routes": [
						{
							"match": [
								{
									"host": [
										"example.com"
									]
								}
							],
							"handle": [
								{
									"handler": "file_server"
								}
							]
						}
					]
				}
			}
		}
	}
}

Export just the listener addresses:

curl "http://localhost:2019/config/apps/http/servers/myserver/listen"
[":443"]

POST /config/[path]

Changes Caddy's configuration at the named path to the JSON body of the request. If the destination value is an array, POST appends; if an object, it creates or replaces.

As a special case, many items can be added to an array if:

  1. the path ends in /...
  2. the element of the path before /... refers to an array
  3. the payload is an array

In this case, the elements in the payload's array will be expanded, and each one will be appended to the destination array. In Go terms, this would have the same effect as:

baseSlice = append(baseSlice, newElems...)

Examples

Add a listener address:

curl -X POST \
	-H "Content-Type: application/json" \
	-d '":8080"' \
	"http://localhost:2019/config/apps/http/servers/myserver/listen"

Add multiple listener addresses:

curl -X POST \
	-H "Content-Type: application/json" \
	-d '[":8080", ":5133"]' \
	"http://localhost:2019/config/apps/http/servers/myserver/listen/..."

PUT /config/[path]

Changes Caddy's configuration at the named path to the JSON body of the request. If the destination value is a position (index) in an array, PUT inserts; if an object, it strictly creates a new value.

Example

Add a listener address in the first slot:

curl -X PUT \
	-H "Content-Type: application/json" \
	-d '":8080"' \
	"http://localhost:2019/config/apps/http/servers/myserver/listen/0"

PATCH /config/[path]

Changes Caddy's configuration at the named path to the JSON body of the request. PATCH strictly replaces an existing value or array element.

Example

Replace the listener addresses:

curl -X PATCH \
	-H "Content-Type: application/json" \
	-d '[":8081", ":8082"]' \
	"http://localhost:2019/config/apps/http/servers/myserver/listen"

DELETE /config/[path]

Removes Caddy's configuration at the named path. DELETE deletes the target value.

Examples

To unload the entire current configuration but leave the process running:

curl -X DELETE "http://localhost:2019/config/"

To stop only one of your HTTP servers:

curl -X DELETE "http://localhost:2019/config/apps/http/servers/myserver"

Using @id in JSON

You can embed IDs in your JSON document for easier direct access to those parts of the JSON.

Simply add a field called "@id" to an object and give it a unique name. For example, if you had a reverse proxy handler that you wanted to access frequently:

{
	"@id": "my_proxy",
	"handler": "reverse_proxy"
}

To use it, simply make a request to the /id/ API endpoint in the same way you would to the corresponding /config/ endpoint, but without the whole path. The ID takes the request directly into that scope of the config for you.

For example, to access the upstreams of the reverse proxy without an ID, the path would be something like

/config/apps/http/servers/myserver/routes/1/handle/0/upstreams

but with an ID, the path becomes

/id/my_proxy/upstreams

which is much easier to remember and write by hand.

GET /reverse_proxy/upstreams

Returns the current status of the configured reverse proxy upstreams (backends) as a JSON document.

curl "http://localhost:2019/reverse_proxy/upstreams" | jq
[
	{"address": "10.0.1.1:80", "healthy": true, "num_requests": 4, "fails": 2},
	{"address": "10.0.1.2:80", "healthy": true, "num_requests": 5, "fails": 4},
	{"address": "10.0.1.3:80", "healthy": true, "num_requests": 3, "fails": 3}
]

Each entry in the JSON array is a configured upstream stored in the global upstream pool.

  • address is the dial address of the upstream. For SRV upstreams, this is the lookup_srv DNS name.
  • healthy reflects whether Caddy believes the upstream to be healthy or not. Note that "health" is a distinct concept from "availability". An unhealthy backend will always be unavailable, but a healthy backend might not be available. Health is a global characteristic regardless of specific reverse proxy handler configuration, whereas availability is determined by the configuration of the specific reverse proxy handler. For example, a healthy backend would be unavailable if the handler is configured to only allow N requests at a time and it currently has N active requests. The "healthy" property does not reflect availability.
  • num_requests is the amount of active requests currently being handled by the upstream.
  • fails the current number of failed requests remembered, as configured by passive health checks.

If your goal is to determine a backend's availability, you will need to cross-check relevant properties of the upstream against the handler configuration you are utilizing. For example, if you've enabled passive health checks for your proxies, then you need to also take into consideration the fails and num_requests values to determine if an upstream is considered available: check that the fails amount is less than your configured maximum amount of failures for your proxy (i.e. max_fails), and that num_requests is less than or equal to your configured amount of maximum requests per upstream (i.e. unhealthy_request_count for the whole proxy, or max_requests for individual upstreams).