# Monitoring

## Monitoring NATS

To monitor the NATS messaging system, `nats-server` provides a lightweight HTTP server on a dedicated monitoring port. The monitoring server provides several endpoints, providing statistics and other information about the following:

* [General Server Information (`/varz`)](#general-information-varz)
* [Connections (`/connz`)](#connection-information-connz)
* [Routing (`/routez`)](#route-information-routez)
* [Gateway (`/gatewayz`)](#gateway-information-gatewayz)
* [Leaf Nodes (`/leafz`)](#leaf-node-information-leafz)
* [Subscription Routing (`/subsz`)](#subscription-routing-information-subsz)
* [Account Information (`/accountz`)](#account-information-accountz)
* [Account Stats (`/accstatz`)](#account-statistics-accstatz)
* [JetStream Information (`/jsz`)](#jetstream-information-jsz)
* [Health (`/healthz`)](#health-healthz)

All endpoints return a JSON object.

Note that info from these monitoring endpoints is also available through [System services](https://docs.nats.io/configuration/sys_accounts#system-account)

The NATS monitoring endpoints support [JSONP](https://en.wikipedia.org/wiki/JSONP) and [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing#How_CORS_works), making it easy to create single page monitoring web applications. Part of the NATS ecosystem is a tool called [nats-top](https://docs.nats.io/using-nats/nats-tools/nats_top) that visualizes data from these endpoints on the command line.

{% hint style="warning" %}
`nats-server` does not have authentication/authorization for the monitoring endpoint. When you plan to open your `nats-server` to the internet make sure to not expose the monitoring port as well. By default, monitoring binds to every interface `0.0.0.0` so consider setting monitoring to `localhost` or have appropriate firewall rules.
{% endhint %}

### Enabling monitoring

Monitoring can be enabled in [server configuration](https://docs.nats.io/configuration#monitoring-and-tracing) or as a server [command-line option](https://docs.nats.io/introduction/flags#server-options). The conventional port is `8222`.

As server configuration:

```yaml
http_port: 8222
```

As a command-line option:

```bash
nats-server -m 8222
```

Once the server is running using one of the two methods, go to <http://localhost:8222> to browse the available endpoints detailed below.

Alternatively, if you have System account enabled, monitoring endpoints available as ["System services"](https://docs.nats.io/running-a-nats-service/configuration/sys_accounts#system-account)

## Monitoring Endpoints

### General Information `(/varz)`

The `/varz` endpoint returns general information about the server state and configuration.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

N/A

#### Example

<https://demo.nats.io:8222/varz>

#### Response

```json
{
  "server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
  "version": "2.0.0",
  "proto": 1,
  "go": "go1.12",
  "host": "0.0.0.0",
  "port": 4222,
  "max_connections": 65536,
  "ping_interval": 120000000000,
  "ping_max": 2,
  "http_host": "0.0.0.0",
  "http_port": 8222,
  "https_port": 0,
  "auth_timeout": 1,
  "max_control_line": 4096,
  "max_payload": 1048576,
  "max_pending": 67108864,
  "cluster": {},
  "gateway": {},
  "leaf": {},
  "tls_timeout": 0.5,
  "write_deadline": 2000000000,
  "start": "2019-06-24T14:24:43.928582-07:00",
  "now": "2019-06-24T14:24:46.894852-07:00",
  "uptime": "2s",
  "mem": 9617408,
  "cores": 4,
  "gomaxprocs": 4,
  "cpu": 0,
  "connections": 0,
  "total_connections": 0,
  "routes": 0,
  "remotes": 0,
  "leafnodes": 0,
  "in_msgs": 0,
  "out_msgs": 0,
  "in_bytes": 0,
  "out_bytes": 0,
  "slow_consumers": 2,
  "subscriptions": 0,
  "http_req_stats": {
    "/": 0,
    "/connz": 0,
    "/gatewayz": 0,
    "/routez": 0,
    "/subsz": 0,
    "/varz": 1
  },
  "config_load_time": "2019-06-24T14:24:43.928582-07:00",
  "slow_consumer_stats": {
    "clients": 1,
    "routes": 1,
    "gateways": 0,
    "leafs": 0
  }
}
```

### Connection Information (`/connz`)

The `/connz` endpoint reports more detailed information on current and recently closed connections. It uses a paging mechanism which defaults to 1024 connections.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument     | Values                        | Description                                                                                                                        |
| ------------ | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| sort         | (*see sort options*)          | Sorts the results. Default is connection ID.                                                                                       |
| auth         | true, 1, false, 0             | Include username. Default is false.                                                                                                |
| subs         | true, 1, false, 0 or `detail` | Include subscriptions. Default is false. When set to `detail` a list with more detailed subscription information will be returned. |
| offset       | number > 0                    | Pagination offset. Default is 0.                                                                                                   |
| limit        | number > 0                    | Number of results to return. Default is 1024.                                                                                      |
| cid          | number, valid id              | Return a connection by its id                                                                                                      |
| state        | open, \*closed, any           | Return connections of particular state. Default is open.                                                                           |
| mqtt\_client | string                        | Filter the connection with this MQTT client ID.                                                                                    |

*The server will default to holding the last 10,000 closed connections.*

**Sort Options**

| Option      | Sort by                                              |
| ----------- | ---------------------------------------------------- |
| cid         | Connection ID                                        |
| start       | Connection start time, same as CID                   |
| subs        | Number of subscriptions                              |
| pending     | Amount of data in bytes waiting to be sent to client |
| msgs\_to    | Number of messages sent                              |
| msgs\_from  | Number of messages received                          |
| bytes\_to   | Number of bytes sent                                 |
| bytes\_from | Number of bytes received                             |
| last        | Last activity                                        |
| idle        | Amount of inactivity                                 |
| uptime      | Lifetime of the connection                           |
| stop        | Stop time for a closed connection                    |
| reason      | Reason for a closed connection                       |
| rtt         | Round trip time                                      |

#### Examples

Get up to 1024 connections: <https://demo.nats.io:8222/connz>

Control limit and offset: <https://demo.nats.io:8222/connz?limit=16&offset=128>.

Get closed connection information: <https://demo.nats.io:8222/connz?state=closed>.

You can also report detailed subscription information on a per connection basis using subs=1. For example: <https://demo.nats.io:8222/connz?limit=1&offset=1&subs=1>.

#### Response

```json
{
  "server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
  "now": "2019-06-24T14:28:16.520365-07:00",
  "num_connections": 2,
  "total": 2,
  "offset": 0,
  "limit": 1024,
  "connections": [
    {
      "cid": 5,
      "kind": "Client",
      "type": "nats",
      "ip": "127.0.0.1",
      "port": 62714,
      "start": "2021-09-09T23:16:43.040862Z",
      "last_activity": "2021-09-09T23:16:43.042364Z",
      "rtt": "95µs",
      "uptime": "5s",
      "idle": "5s",
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "name": "NATS Benchmark",
      "lang": "go",
      "version": "1.12.1"
    },
    {
      "cid": 6,
      "kind": "Client",
      "type": "nats",
      "ip": "127.0.0.1",
      "port": 62715,
      "start": "2021-09-09T23:16:43.042557Z",
      "last_activity": "2021-09-09T23:16:43.042811Z",
      "rtt": "100µs",
      "uptime": "5s",
      "idle": "5s",
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "name": "NATS Benchmark",
      "lang": "go",
      "version": "1.12.1"
    },
    {
      "cid": 7,
      "kind": "Client",
      "type": "mqtt",
      "ip": "::1",
      "port": 62718,
      "start": "2021-09-09T23:16:45.391459Z",
      "last_activity": "2021-09-09T23:16:45.395869Z",
      "rtt": "0s",
      "uptime": "2s",
      "idle": "2s",
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 2,
      "mqtt_client": "mqtt_sub"
    }
  ]
}
```

### Route Information (`/routez`)

The `/routez` endpoint reports information on active routes for a cluster. Routes are expected to be low, so there is no paging mechanism with this endpoint.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument | Values                        | Description                                                                                                                        |
| -------- | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| subs     | true, 1, false, 0 or `detail` | Include subscriptions. Default is false. When set to `detail` a list with more detailed subscription information will be returned. |

As noted above, the `routez` endpoint does support the `subs` argument from the `/connz` endpoint. For example: <https://demo.nats.io:8222/routez?subs=1>

#### Example

* Get route information: <https://demo.nats.io:8222/routez?subs=1>

#### Response

```json
{
  "server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
  "now": "2019-06-24T14:29:16.046656-07:00",
  "num_routes": 1,
  "routes": [
    {
      "rid": 1,
      "remote_id": "de475c0041418afc799bccf0fdd61b47",
      "did_solicit": true,
      "ip": "127.0.0.1",
      "port": 61791,
      "pending_size": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 0
    }
  ]
}
```

### Gateway Information (`/gatewayz`)

The `/gatewayz` endpoint reports information about gateways used to create a NATS supercluster. Like routes, the number of gateways are expected to be low, so there is no paging mechanism with this endpoint.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument  | Values            | Description                                      |
| --------- | ----------------- | ------------------------------------------------ |
| accs      | true, 1, false, 0 | Include account information. Default is false.   |
| gw\_name  | string            | Return only remote gateways with this name.      |
| acc\_name | string            | Limit the list of accounts to this account name. |

#### Examples

* Retrieve Gateway Information: <https://demo.nats.io:8222/gatewayz>

#### Response

```json
{
  "server_id": "NANVBOU62MDUWTXWRQ5KH3PSMYNCHCEUHQV3TW3YH7WZLS7FMJE6END6",
  "now": "2019-07-24T18:02:55.597398-06:00",
  "name": "region1",
  "host": "2601:283:4601:1350:1895:efda:2010:95a1",
  "port": 4501,
  "outbound_gateways": {
    "region2": {
      "configured": true,
      "connection": {
        "cid": 7,
        "ip": "127.0.0.1",
        "port": 5500,
        "start": "2019-07-24T18:02:48.765621-06:00",
        "last_activity": "2019-07-24T18:02:48.765621-06:00",
        "uptime": "6s",
        "idle": "6s",
        "pending_bytes": 0,
        "in_msgs": 0,
        "out_msgs": 0,
        "in_bytes": 0,
        "out_bytes": 0,
        "subscriptions": 0,
        "name": "NCXBIYWT7MV7OAQTCR4QTKBN3X3HDFGSFWTURTCQ22ZZB6NKKJPO7MN4"
      }
    },
    "region3": {
      "configured": true,
      "connection": {
        "cid": 5,
        "ip": "::1",
        "port": 6500,
        "start": "2019-07-24T18:02:48.764685-06:00",
        "last_activity": "2019-07-24T18:02:48.764685-06:00",
        "uptime": "6s",
        "idle": "6s",
        "pending_bytes": 0,
        "in_msgs": 0,
        "out_msgs": 0,
        "in_bytes": 0,
        "out_bytes": 0,
        "subscriptions": 0,
        "name": "NCVS7Q65WX3FGIL2YQRLI77CE6MQRWO2Y453HYVLNMBMTVLOKMPW7R6K"
      }
    }
  },
  "inbound_gateways": {
    "region2": [
      {
        "configured": false,
        "connection": {
          "cid": 9,
          "ip": "::1",
          "port": 52029,
          "start": "2019-07-24T18:02:48.76677-06:00",
          "last_activity": "2019-07-24T18:02:48.767096-06:00",
          "uptime": "6s",
          "idle": "6s",
          "pending_bytes": 0,
          "in_msgs": 0,
          "out_msgs": 0,
          "in_bytes": 0,
          "out_bytes": 0,
          "subscriptions": 0,
          "name": "NCXBIYWT7MV7OAQTCR4QTKBN3X3HDFGSFWTURTCQ22ZZB6NKKJPO7MN4"
        }
      }
    ],
    "region3": [
      {
        "configured": false,
        "connection": {
          "cid": 4,
          "ip": "::1",
          "port": 52025,
          "start": "2019-07-24T18:02:48.764577-06:00",
          "last_activity": "2019-07-24T18:02:48.764994-06:00",
          "uptime": "6s",
          "idle": "6s",
          "pending_bytes": 0,
          "in_msgs": 0,
          "out_msgs": 0,
          "in_bytes": 0,
          "out_bytes": 0,
          "subscriptions": 0,
          "name": "NCVS7Q65WX3FGIL2YQRLI77CE6MQRWO2Y453HYVLNMBMTVLOKMPW7R6K"
        }
      },
      {
        "configured": false,
        "connection": {
          "cid": 8,
          "ip": "127.0.0.1",
          "port": 52026,
          "start": "2019-07-24T18:02:48.766173-06:00",
          "last_activity": "2019-07-24T18:02:48.766999-06:00",
          "uptime": "6s",
          "idle": "6s",
          "pending_bytes": 0,
          "in_msgs": 0,
          "out_msgs": 0,
          "in_bytes": 0,
          "out_bytes": 0,
          "subscriptions": 0,
          "name": "NCKCYK5LE3VVGOJQ66F65KA27UFPCLBPX4N4YOPOXO3KHGMW24USPCKN"
        }
      }
    ]
  }
}
```

### Leaf Node Information (`/leafz`)

The `/leafz` endpoint reports detailed information about the leaf node connections.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument | Values            | Description                                       |
| -------- | ----------------- | ------------------------------------------------- |
| subs     | true, 1, false, 0 | Include internal subscriptions. Default is false. |

As noted above, the `leafz` endpoint does support the `subs` argument from the `/connz` endpoint. For example: <https://demo.nats.io:8222/leafz?subs=1>

#### Example

* Get leaf nodes information: <https://demo.nats.io:8222/leafz?subs=1>

#### Response

```json
{
  "server_id": "NC2FJCRMPBE5RI5OSRN7TKUCWQONCKNXHKJXCJIDVSAZ6727M7MQFVT3",
  "now": "2019-08-27T09:07:05.841132-06:00",
  "leafnodes": 1,
  "leafs": [
    {
      "account": "$G",
      "ip": "127.0.0.1",
      "port": 6223,
      "rtt": "200µs",
      "in_msgs": 0,
      "out_msgs": 10000,
      "in_bytes": 0,
      "out_bytes": 1280000,
      "subscriptions": 1,
      "subscriptions_list": ["foo"]
    }
  ]
}
```

### Subscription Routing Information (`/subsz`)

The `/subsz` endpoint reports detailed information about the current subscriptions and the routing data structure. It is not normally used.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument | Values            | Description                                   |
| -------- | ----------------- | --------------------------------------------- |
| subs     | true, 1, false, 0 | Include subscriptions. Default is false.      |
| offset   | integer > 0       | Pagination offset. Default is 0.              |
| limit    | integer > 0       | Number of results to return. Default is 1024. |
| test     | subject           | Test whether a subsciption exists.            |

#### Example

* Get subscription routing information: <https://demo.nats.io:8222/subsz>

#### Response

```json
{
  "num_subscriptions": 2,
  "num_cache": 0,
  "num_inserts": 2,
  "num_removes": 0,
  "num_matches": 0,
  "cache_hit_rate": 0,
  "max_fanout": 0,
  "avg_fanout": 0
}
```

### Account Information (`/accountz`)

The `/accountz` endpoint reports information on a server's active accounts. The default behavior is to return a list of all accounts known to the server.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

| Argument | Value        | Description                                                                                                    |
| -------- | ------------ | -------------------------------------------------------------------------------------------------------------- |
| acc      | account name | Include metrics for the specified account. Default is empty. When not set, a list of all accounts is included. |

#### Example

* Get list of all accounts: <https://demo.nats.io:8222/accountz>
* Get details for specific account `$G`: <https://demo.nats.io:8222/accountz?acc=$G>

#### Response

Default behavior:

```json
{
  "server_id": "NAB2EEQ3DLS2BHU4K2YMXMPIOOOAOFOAQAC5NQRIEUI4BHZKFBI4ZU4A",
  "now": "2021-02-08T17:31:29.551146-05:00",
  "system_account": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
  "accounts": ["AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5", "$G"]
}
```

Retrieve specific account:

```json
{
  "server_id": "NAB2EEQ3DLS2BHU4K2YMXMPIOOOAOFOAQAC5NQRIEUI4BHZKFBI4ZU4A",
  "now": "2021-02-08T17:37:55.80856-05:00",
  "system_account": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
  "account_detail": {
    "account_name": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
    "update_time": "2021-02-08T17:31:22.390334-05:00",
    "is_system": true,
    "expired": false,
    "complete": true,
    "jetstream_enabled": false,
    "leafnode_connections": 0,
    "client_connections": 0,
    "subscriptions": 42,
    "exports": [
      {
        "subject": "$SYS.DEBUG.SUBSCRIBERS",
        "type": "service",
        "response_type": "Singleton"
      }
    ],
    "jwt": "eyJ0eXAiOiJqd3QiLCJhbGciOiJlZDI1NTE5In0.eyJqdGkiOiJVVlU2VEpXRU8zS0hYWTZVMkgzM0RCVklET1A3U05DTkJPMlM0M1dPNUM2T1RTTDNVSUxBIiwiaWF0IjoxNjAzNDczNzg4LCJpc3MiOiJPQlU1TzVGSjMyNFVEUFJCSVZSR0Y3Q05FT0hHTFBTN0VZUEJUVlFaS1NCSElJWklCNkhENjZKRiIsIm5hbWUiOiJTWVMiLCJzdWIiOiJBQUFYQVVWU0dLN1RDUkhGSVJBUzRTWVhWSjc2RVdETU5YWk02QVJGR1hQN0JBU05ER0xLVTdBNSIsInR5cGUiOiJhY2NvdW50IiwibmF0cyI6eyJsaW1pdHMiOnsic3VicyI6LTEsImNvbm4iOi0xLCJsZWFmIjotMSwiaW1wb3J0cyI6LTEsImV4cG9ydHMiOi0xLCJkYXRhIjotMSwicGF5bG9hZCI6LTEsIndpbGRjYXJkcyI6dHJ1ZX19fQ.CeGo16i5oD0b1uBJ8UdGmLH-l9dL8yNqXHggkAt2T5c88fM7k4G08wLguMAnlvzrdlYvdZvOx_5tHLuDZmGgCg",
    "issuer_key": "OBU5O5FJ324UDPRBIVRGF7CNEOHGLPS7EYPBTVQZKSBHIIZIB6HD66JF",
    "name_tag": "SYS",
    "decoded_jwt": {
      "jti": "UVU6TJWEO3KHXY6U2H33DBVIDOP7SNCNBO2S43WO5C6OTSL3UILA",
      "iat": 1603473788,
      "iss": "OBU5O5FJ324UDPRBIVRGF7CNEOHGLPS7EYPBTVQZKSBHIIZIB6HD66JF",
      "name": "SYS",
      "sub": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
      "nats": {
        "limits": {
          "subs": -1,
          "data": -1,
          "payload": -1,
          "imports": -1,
          "exports": -1,
          "wildcards": true,
          "conn": -1,
          "leaf": -1
        },
        "default_permissions": {
          "pub": {},
          "sub": {}
        },
        "type": "account",
        "version": 1
      }
    },
    "sublist_stats": {
      "num_subscriptions": 42,
      "num_cache": 6,
      "num_inserts": 42,
      "num_removes": 0,
      "num_matches": 6,
      "cache_hit_rate": 0,
      "max_fanout": 1,
      "avg_fanout": 0.8333333333333334
    }
  }
}
```

### Account Statistics (`/accstatz`)

The `/accstatz` endpoint reports per-account statistics such as the number of connections, messages/bytes in/out, etc.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument | Values            | Description                                                                           |
| -------- | ----------------- | ------------------------------------------------------------------------------------- |
| unused   | true, 1, false, 0 | If true, include accounts that do not have any current connections. Default is false. |

#### Examples

* Accounts with active connections - <https://demo.nats.io:8222/accstatz>
* Include ones without any connections (in this case `$SYS`)- <https://demo.nats.io:8222/accstatz?unused=1>

#### Response

```json
{
  "server_id": "NDJ5M4F5WAIBUA26NJ3QMH532AQPN7QNTJP3Y4SBHSHL4Y7QUAKNJEAF",
  "now": "2022-10-19T17:16:20.881296749Z",
  "account_statz": [
    {
      "acc": "default",
      "conns": 31,
      "leafnodes": 2,
      "total_conns": 33,
      "num_subscriptions": 45,
      "sent": {
        "msgs": 1876970,
        "bytes": 246705616
      },
      "received": {
        "msgs": 1347454,
        "bytes": 219438308
      },
      "slow_consumers": 29
    },
    {
      "acc": "$G",
      "conns": 1,
      "leafnodes": 0,
      "total_conns": 1,
      "num_subscriptions": 3,
      "sent": {
        "msgs": 0,
        "bytes": 0
      },
      "received": {
        "msgs": 107,
        "bytes": 1094
      },
      "slow_consumers": 0
    }
  ]
}
```

### JetStream Information (`/jsz`)

The `/jsz` endpoint reports more detailed information on JetStream. For accounts, it uses a paging mechanism that defaults to 1024 connections.

> **Note:** If you're in a clustered environment, it is recommended to retrieve the information from the stream's leader in order to get the most accurate and up-to-date data.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument    | Values            | Description                                                                                      |
| ----------- | ----------------- | ------------------------------------------------------------------------------------------------ |
| acc         | account name      | Include metrics for the specified account. Default is unset.                                     |
| accounts    | true, 1, false, 0 | Include account specific JetStream information. Default is false.                                |
| streams     | true, 1, false, 0 | Include streams. When set, implies `accounts=true`. Default is false.                            |
| consumers   | true, 1, false, 0 | Include consumer. When set, implies `streams=true`. Default is false.                            |
| config      | true, 1, false, 0 | When stream or consumer are requested, include their respective configuration. Default is false. |
| leader-only | true, 1, false, 0 | Only the leader responds. Default is false.                                                      |
| offset      | number > 0        | Pagination offset. Default is 0.                                                                 |
| limit       | number > 0        | Number of results to return. Default is 1024.                                                    |
| raft        | true, 1, false, 0 | Include information details about the Raft group. Default is false.                              |

#### Examples

Get basic JetStream information: <https://demo.nats.io:8222/jsz>

Request accounts and control limit and offset: <https://demo.nats.io:8222/jsz?accounts=true&limit=16&offset=128>.

You can also report detailed consumer information on a per connection basis using consumer=true. For example: <https://demo.nats.io:8222/jsz?consumers=true>.

#### Response

```json
{
  "server_id": "NCVIDODSZ45C5OD67ZD7EJUIJPQDP6CM74SJX6TJIF2G7NLYS5LCVYHS",
  "now": "2021-02-08T19:08:30.555533-05:00",
  "config": {
    "max_memory": 10485760,
    "max_storage": 10485760,
    "store_dir": "/var/folders/9h/6g_c9l6n6bb8gp331d_9y0_w0000gn/T/srv_7500251552558",
    "unique_tag": "az"
  },
  "memory": 0,
  "storage": 66,
  "api": {
    "total": 5,
    "errors": 0
  },
  "total_streams": 1,
  "total_consumers": 1,
  "total_messages": 1,
  "total_message_bytes": 33,
  "meta_cluster": {
    "name": "cluster_name",
    "replicas": [
      {
        "name": "server_5500",
        "current": false,
        "active": 2932926000
      }
    ]
  },
  "account_details": [
    {
      "name": "BCC_TO_HAVE_ONE_EXTRA",
      "id": "BCC_TO_HAVE_ONE_EXTRA",
      "memory": 0,
      "storage": 0,
      "api": {
        "total": 0,
        "errors": 0
      }
    },
    {
      "name": "ACC",
      "id": "ACC",
      "memory": 0,
      "storage": 66,
      "api": {
        "total": 5,
        "errors": 0
      },
      "stream_detail": [
        {
          "name": "my-stream-replicated",
          "cluster": {
            "name": "cluster_name",
            "replicas": [
              {
                "name": "server_5500",
                "current": false,
                "active": 2931517000
              }
            ]
          },
          "state": {
            "messages": 1,
            "bytes": 33,
            "first_seq": 1,
            "first_ts": "2021-02-09T00:08:27.623735Z",
            "last_seq": 1,
            "last_ts": "2021-02-09T00:08:27.623735Z",
            "consumer_count": 1
          },
          "consumer_detail": [
            {
              "stream_name": "my-stream-replicated",
              "name": "my-consumer-replicated",
              "created": "2021-02-09T00:08:27.427631Z",
              "delivered": {
                "consumer_seq": 0,
                "stream_seq": 0
              },
              "ack_floor": {
                "consumer_seq": 0,
                "stream_seq": 0
              },
              "num_ack_pending": 0,
              "num_redelivered": 0,
              "num_waiting": 0,
              "num_pending": 1,
              "cluster": {
                "name": "cluster_name",
                "replicas": [
                  {
                    "name": "server_5500",
                    "current": false,
                    "active": 2933232000
                  }
                ]
              }
            }
          ]
        }
      ]
    }
  ]
}
```

### Health (`/healthz`)

The `/healthz` endpoint returns OK if the server is able to accept connections.

| Result  | Return Code       |
| ------- | ----------------- |
| Success | 200 (OK)          |
| Error   | 400 (Bad Request) |

#### Arguments

| Argument        | Values  | Description                                                                                 |
| --------------- | ------- | ------------------------------------------------------------------------------------------- |
| js-enabled-only | true, 1 | Returns an error if JetStream is disabled.                                                  |
| js-server-only  | true, 1 | Skip health check of accounts, streams, and consumers.                                      |
| js-enabled      | true, 1 | Returns an error if JetStream is disabled. (**Deprecated**: use `js-enabled-only` instead). |

#### Example

* Default - <https://demo.nats.io:8222/healthz>
* Expect JetStream - <https://demo.nats.io:8222/healthz?js-enabled-only=true>

#### Response

```json
{ "status": "ok" }
```

## Creating Monitoring Applications

NATS monitoring endpoints support [JSONP](https://en.wikipedia.org/wiki/JSONP) and [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing#How_CORS_works). You can easily create single page web applications for monitoring. To do this you simply pass the `callback` query parameter to any endpoint.

For example:

```
https://demo.nats.io:8222/connz?callback=cb
```

Here is a JQuery example implementation:

```javascript
$.getJSON("https://demo.nats.io:8222/connz?callback=?", function (data) {
  console.log(data);
});
```

## Monitoring Tools

In addition to writing custom monitoring tools, you can monitor nats-server in Prometheus. The [Prometheus NATS Exporter](https://github.com/nats-io/prometheus-nats-exporter) allows you to configure the metrics you want to observe and store in Prometheus, and there are Grafana dashboards available for you to visualize the server metrics.

See the [Walkthrough of Monitoring NATS with Prometheus and Grafana](https://github.com/nats-io/prometheus-nats-exporter/tree/main/walkthrough) for more details.