diff --git a/source/index.html.md b/source/index.html.md
index e18397f844f..50308341eb7 100644
--- a/source/index.html.md
+++ b/source/index.html.md
@@ -787,6 +787,71 @@ curl "https://my.timelline.is/api/v3p/zones/5d1f0bf741092775efbddd71/ptz" \
> The above command returns 200 status without body
+## Relay Outputs
+This endpoint returns a list of relay outputs for zone.
+### HTTP Request
+`GET https://my.timeline.is/api/v3p/:zone_id/relay_outputs`
+
+**Parameters**
+
+| Name | Located in | Description | Required | Type |
+| ---- | ---------- | ----------- | -------- | ---- |
+
+
+```shell
+curl "https://my.timelline.is/api/v3p/zones/5d1f0bf741092775efbddd71/relay_outputs" \
+ --request GET \
+ -H "Authorization: Bearer YOUR_OAUTH_TOKEN" \
+ -H "Content-Type: application/json"
+```
+
+> The above command returns
+
+```json
+{
+ "relay_outputs": [{
+ "properties": {
+ "mode": "Bistable",
+ "delay_time": "PT3S",
+ "idle_state": "closed"
+ },
+ "@token": "2"
+ },
+ {
+ "properties": {
+ "mode": "Monostable",
+ "delay_time": "PT5S",
+ "idle_state": "open"
+ },
+ "@token": "3"
+ }
+ ]
+}
+```
+
+
+## Relay
+This endpoint allows you to change the zone relay status by its token.
+### HTTP Request
+`POST https://my.timeline.is/api/v3p/:zone_id/relay`
+
+**Parameters**
+
+| Name | Located in | Description | Required | Type |
+| ---- | ---------- | ----------- | -------- | ---- |
+| relay | query/body | Relay token/number | Yes | Integer |
+| state | query/body | Sate ON/OFF (default true) | No | Boolean |
+
+
+```shell
+curl "https://my.timelline.is/api/v3p/zones/5d1f0bf741092775efbddd71/relay" \
+ --data '{"relay": 3,"state": true}' \
+ --request POST \
+ -H "Authorization: Bearer YOUR_OAUTH_TOKEN" \
+ -H "Content-Type: application/json"
+```
+
+> The above command returns 200 status without body
## Audio challenge
This endpoint allows you play audio announcement on Tetherbox.