# 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](/running-a-nats-service/configuration/sys_accounts.md#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](/using-nats/nats-tools/nats_top.md) 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](/running-a-nats-service/configuration.md#monitoring-and-tracing) or as a server [command-line option](/running-a-nats-service/introduction/flags.md#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.

### Commercial Options

If you want a "batteries-included" approach to high-cardinality NATS monitoring and observability, try the standalone [Synadia Insights](https://www.synadia.com/insights).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.nats.io/running-a-nats-service/nats_admin/monitoring.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.