20 KiB
Subscribe via API
You can create and subscribe to a topic in the web UI, via the phone app, via the ntfy CLI, or in your own app or script by subscribing the API. This page describes how to subscribe via API. You may also want to check out the page that describes how to publish messages.
You can consume the subscription API as either a simple HTTP stream (JSON, SSE or raw), or via WebSockets. Both are incredibly simple to use.
HTTP stream
The HTTP stream-based API relies on a simple GET request with a streaming HTTP response, i.e you open a GET request and the connection stays open forever, sending messages back as they come in. There are three different API endpoints, which only differ in the response format:
- JSON stream:
<topic>/json
returns a JSON stream, with one JSON message object per line - SSE stream:
<topic>/sse
returns messages as Server-Sent Events (SSE), which can be used with EventSource - Raw stream:
<topic>/raw
returns messages as raw text, with one line per message
Subscribe as JSON stream
Here are a few examples of how to consume the JSON endpoint (<topic>/json
). For almost all languages, this is the
recommended way to subscribe to a topic. The notable exception is JavaScript, for which the
SSE/EventSource stream is much easier to work with.
=== "Command line (curl)"
$ curl -s ntfy.sh/disk-alerts/json {"id":"SLiKI64DOt","time":1635528757,"event":"open","topic":"mytopic"} {"id":"hwQ2YpKdmg","time":1635528741,"event":"message","topic":"mytopic","message":"Disk full"} {"id":"DGUDShMCsc","time":1635528787,"event":"keepalive","topic":"mytopic"} ...
=== "ntfy CLI"
$ ntfy subcribe disk-alerts {"id":"hwQ2YpKdmg","time":1635528741,"event":"message","topic":"mytopic","message":"Disk full"} ...
=== "HTTP" ``` http GET /disk-alerts/json HTTP/1.1 Host: ntfy.sh
HTTP/1.1 200 OK
Content-Type: application/x-ndjson; charset=utf-8
Transfer-Encoding: chunked
{"id":"SLiKI64DOt","time":1635528757,"event":"open","topic":"mytopic"}
{"id":"hwQ2YpKdmg","time":1635528741,"event":"message","topic":"mytopic","message":"Disk full"}
{"id":"DGUDShMCsc","time":1635528787,"event":"keepalive","topic":"mytopic"}
...
```
=== "Go"
go resp, err := http.Get("https://ntfy.sh/disk-alerts/json") if err != nil { log.Fatal(err) } defer resp.Body.Close() scanner := bufio.NewScanner(resp.Body) for scanner.Scan() { println(scanner.Text()) }
=== "Python"
python resp = requests.get("https://ntfy.sh/disk-alerts/json", stream=True) for line in resp.iter_lines(): if line: print(line)
=== "PHP"
php-inline $fp = fopen('https://ntfy.sh/disk-alerts/json', 'r'); if (!$fp) die('cannot open stream'); while (!feof($fp)) { echo fgets($fp, 2048); flush(); } fclose($fp);
Subscribe as SSE stream
Using EventSource in JavaScript, you can consume notifications via a Server-Sent Events (SSE) stream. It's incredibly easy to use. Here's what it looks like. You may also want to check out the live example.
=== "Command line (curl)" ``` $ curl -s ntfy.sh/mytopic/sse event: open data: {"id":"weSj9RtNkj","time":1635528898,"event":"open","topic":"mytopic"}
data: {"id":"p0M5y6gcCY","time":1635528909,"event":"message","topic":"mytopic","message":"Hi!"}
event: keepalive
data: {"id":"VNxNIg5fpt","time":1635528928,"event":"keepalive","topic":"test"}
...
```
=== "HTTP" ``` http GET /mytopic/sse HTTP/1.1 Host: ntfy.sh
HTTP/1.1 200 OK
Content-Type: text/event-stream; charset=utf-8
Transfer-Encoding: chunked
event: open
data: {"id":"weSj9RtNkj","time":1635528898,"event":"open","topic":"mytopic"}
data: {"id":"p0M5y6gcCY","time":1635528909,"event":"message","topic":"mytopic","message":"Hi!"}
event: keepalive
data: {"id":"VNxNIg5fpt","time":1635528928,"event":"keepalive","topic":"test"}
...
```
=== "JavaScript"
javascript const eventSource = new EventSource('https://ntfy.sh/mytopic/sse'); eventSource.onmessage = (e) => { console.log(e.data); };
Subscribe as raw stream
The /raw
endpoint will output one line per message, and will only include the message body. It's useful for extremely
simple scripts, and doesn't include all the data. Additional fields such as priority,
tags or message title are not included in this output
format. Keepalive messages are sent as empty lines.
=== "Command line (curl)" ``` $ curl -s ntfy.sh/disk-alerts/raw
Disk full
...
```
=== "HTTP" ``` http GET /disk-alerts/raw HTTP/1.1 Host: ntfy.sh
HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Transfer-Encoding: chunked
Disk full
...
```
=== "Go"
go resp, err := http.Get("https://ntfy.sh/disk-alerts/raw") if err != nil { log.Fatal(err) } defer resp.Body.Close() scanner := bufio.NewScanner(resp.Body) for scanner.Scan() { println(scanner.Text()) }
=== "Python"
python resp = requests.get("https://ntfy.sh/disk-alerts/raw", stream=True) for line in resp.iter_lines(): if line: print(line)
=== "PHP"
php-inline $fp = fopen('https://ntfy.sh/disk-alerts/raw', 'r'); if (!$fp) die('cannot open stream'); while (!feof($fp)) { echo fgets($fp, 2048); flush(); } fclose($fp);
WebSockets
You may also subscribe to topics via WebSockets, which is also widely
supported in many languages. Most notably, WebSockets are natively supported in JavaScript. On the command line,
I recommend websocat, a fantastic tool similar to socat
or curl
, but specifically
for WebSockets.
The WebSockets endpoint is available at <topic>/ws
and returns messages as JSON objects similar to the
JSON stream endpoint.
=== "Command line (websocat)"
$ websocat wss://ntfy.sh/mytopic/ws {"id":"qRHUCCvjj8","time":1642307388,"event":"open","topic":"mytopic"} {"id":"eOWoUBJ14x","time":1642307754,"event":"message","topic":"mytopic","message":"hi there"}
=== "HTTP" ``` http GET /disk-alerts/ws HTTP/1.1 Host: ntfy.sh Upgrade: websocket Connection: Upgrade
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
...
```
=== "Go"
go import "github.com/gorilla/websocket" ws, _, _ := websocket.DefaultDialer.Dial("wss://ntfy.sh/mytopic/ws", nil) messageType, data, err := ws.ReadMessage() ...
=== "JavaScript"
javascript const socket = new WebSocket('wss://ntfy.sh/mytopic/ws'); socket.addEventListener('message', function (event) { console.log(event.data); });
Advanced features
Poll for messages
You can also just poll for messages if you don't like the long-standing connection using the poll=1
query parameter. The connection will end after all available messages have been read. This parameter can be
combined with since=
(defaults to since=all
).
curl -s "ntfy.sh/mytopic/json?poll=1"
Fetch cached messages
Messages may be cached for a couple of hours (see message caching) to account for network
interruptions of subscribers. If the server has configured message caching, you can read back what you missed by using
the since=
query parameter. It takes a duration (e.g. 10m
or 30s
), a Unix timestamp (e.g. 1635528757
),
a message ID (e.g. nFS3knfcQ1xe
), or all
(all cached messages).
curl -s "ntfy.sh/mytopic/json?since=10m"
curl -s "ntfy.sh/mytopic/json?since=1645970742"
curl -s "ntfy.sh/mytopic/json?since=nFS3knfcQ1xe"
Fetch scheduled messages
Messages that are scheduled to be delivered at a later date are not typically
returned when subscribing via the API, which makes sense, because after all, the messages have technically not been
delivered yet. To also return scheduled messages from the API, you can use the scheduled=1
(alias: sched=1
)
parameter (makes most sense with the poll=1
parameter):
curl -s "ntfy.sh/mytopic/json?poll=1&sched=1"
Filter messages
You can filter which messages are returned based on the well-known message fields id
, message
, title
, priority
and
tags
. Here's an example that only returns messages of high or urgent priority that contains the both tags
"zfs-error" and "error". Note that the priority
filter is a logical OR and the tags
filter is a logical AND.
$ curl "ntfy.sh/alerts/json?priority=high&tags=zfs-error"
{"id":"0TIkJpBcxR","time":1640122627,"event":"open","topic":"alerts"}
{"id":"X3Uzz9O1sM","time":1640122674,"event":"message","topic":"alerts","priority":4,
"tags":["error", "zfs-error"], "message":"ZFS pool corruption detected"}
Available filters (all case-insensitive):
Filter variable | Alias | Example | Description |
---|---|---|---|
id |
X-ID |
ntfy.sh/mytopic/json?poll=1&id=pbkiz8SD7ZxG |
Only return messages that match this exact message ID |
message |
X-Message , m |
ntfy.sh/mytopic/json?message=lalala |
Only return messages that match this exact message string |
title |
X-Title , t |
ntfy.sh/mytopic/json?title=some+title |
Only return messages that match this exact title string |
priority |
X-Priority , prio , p |
ntfy.sh/mytopic/json?p=high,urgent |
Only return messages that match any priority listed (comma-separated) |
tags |
X-Tags , tag , ta |
ntfy.sh/mytopic?/jsontags=error,alert |
Only return messages that match all listed tags (comma-separated) |
Subscribe to multiple topics
It's possible to subscribe to multiple topics in one HTTP call by providing a comma-separated list of topics in the URL. This allows you to reduce the number of connections you have to maintain:
$ curl -s ntfy.sh/mytopic1,mytopic2/json
{"id":"0OkXIryH3H","time":1637182619,"event":"open","topic":"mytopic1,mytopic2,mytopic3"}
{"id":"dzJJm7BCWs","time":1637182634,"event":"message","topic":"mytopic1","message":"for topic 1"}
{"id":"Cm02DsxUHb","time":1637182643,"event":"message","topic":"mytopic2","message":"for topic 2"}
Authentication
Depending on whether the server is configured to support access control, some topics may be read/write protected so that only users with the correct credentials can subscribe or publish to them. To publish/subscribe to protected topics, you can use Basic Auth with a valid username/password. For your self-hosted server, be sure to use HTTPS to avoid eavesdropping and exposing your password.
curl -u phil:mypass -s "https://ntfy.example.com/mytopic/json"
JSON message format
Both the /json
endpoint and the /sse
endpoint return a JSON
format of the message. It's very straight forward:
Message:
Field | Required | Type | Example | Description |
---|---|---|---|---|
id |
✔️ | string | hwQ2YpKdmg |
Randomly chosen message identifier |
time |
✔️ | number | 1635528741 |
Message date time, as Unix time stamp |
event |
✔️ | open , keepalive , message , or poll_request |
message |
Message type, typically you'd be only interested in message |
topic |
✔️ | string | topic1,topic2 |
Comma-separated list of topics the message is associated with; only one for all message events, but may be a list in open events |
message |
- | string | Some message |
Message body; always present in message events |
title |
- | string | Some title |
Message title; if not set defaults to ntfy.sh/<topic> |
tags |
- | string array | ["tag1","tag2"] |
List of tags that may or not map to emojis |
priority |
- | 1, 2, 3, 4, or 5 | 4 |
Message priority with 1=min, 3=default and 5=max |
click |
- | URL | https://example.com |
Website opened when notification is clicked |
actions |
- | JSON array | see actions buttons | Action buttons that can be displayed in the notification |
attachment |
- | JSON object | see below | Details about an attachment (name, URL, size, ...) |
Attachment (part of the message, see attachments for details):
Field | Required | Type | Example | Description |
---|---|---|---|---|
name |
✔️ | string | attachment.jpg |
Name of the attachment, can be overridden with X-Filename , see attachments |
url |
✔️ | URL | https://example.com/file.jpg |
URL of the attachment |
type |
-️ | mime type | image/jpeg |
Mime type of the attachment, only defined if attachment was uploaded to ntfy server |
size |
-️ | number | 33848 |
Size of the attachment in bytes, only defined if attachment was uploaded to ntfy server |
expires |
-️ | number | 1635528741 |
Attachment expiry date as Unix time stamp, only defined if attachment was uploaded to ntfy server |
Here's an example for each message type:
=== "Notification message"
json { "id": "sPs71M8A2T", "time": 1643935928, "event": "message", "topic": "mytopic", "priority": 5, "tags": [ "warning", "skull" ], "click": "https://homecam.mynet.lan/incident/1234", "attachment": { "name": "camera.jpg", "type": "image/png", "size": 33848, "expires": 1643946728, "url": "https://ntfy.sh/file/sPs71M8A2T.png" }, "title": "Unauthorized access detected", "message": "Movement detected in the yard. You better go check" }
=== "Notification message (minimal)"
json { "id": "wze9zgqK41", "time": 1638542110, "event": "message", "topic": "phil_alerts", "message": "Remote access to phils-laptop detected. Act right away." }
=== "Open message"
json { "id": "2pgIAaGrQ8", "time": 1638542215, "event": "open", "topic": "phil_alerts" }
=== "Keepalive message"
json { "id": "371sevb0pD", "time": 1638542275, "event": "keepalive", "topic": "phil_alerts" }
=== "Poll request message"
json { "id": "371sevb0pD", "time": 1638542275, "event": "poll_request", "topic": "phil_alerts" }
List of all parameters
The following is a list of all parameters that can be passed when subscribing to a message. Parameter names are case-insensitive, and can be passed as HTTP headers or query parameters in the URL. They are listed in the table in their canonical form.
Parameter | Aliases (case-insensitive) | Description |
---|---|---|
poll |
X-Poll , po |
Return cached messages and close connection |
since |
X-Since , si |
Return cached messages since timestamp, duration or message ID |
scheduled |
X-Scheduled , sched |
Include scheduled/delayed messages in message list |
id |
X-ID |
Filter: Only return messages that match this exact message ID |
message |
X-Message , m |
Filter: Only return messages that match this exact message string |
title |
X-Title , t |
Filter: Only return messages that match this exact title string |
priority |
X-Priority , prio , p |
Filter: Only return messages that match any priority listed (comma-separated) |
tags |
X-Tags , tag , ta |
Filter: Only return messages that match all listed tags (comma-separated) |