ntfy/docs/subscribe/api.md

Subscribe via API

You can create and subscribe to a topic either in the web UI, via the phone app, 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.

The subscription API relies on a simple HTTP 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"} ...

=== "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);

JSON message format

Both the /json endpoint and the /sse endpoint return a JSON format of the message. It's very straight forward:

Field	Required	Type	Example	Description
id	✔️	string	hwQ2YpKdmg	Randomly chosen message identifier
time	✔️	int	1635528741	Message date time, as Unix time stamp
event	✔️	open, keepalive or message	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

Here's an example for each message type:

=== "Notification message" json { "id": "wze9zgqK41", "time": 1638542110, "event": "message", "topic": "phil_alerts", "priority": 5, "tags": [ "warning", "skull" ], "title": "Unauthorized access detected", "message": "Remote access to phils-laptop detected. Act right away." }

=== "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" }

Advanced features

Fetching 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 either a duration (e.g. 10m or 30s), a Unix timestamp (e.g. 1635528757) or all (all cached messages).

curl -s "ntfy.sh/mytopic/json?since=10m"

Polling 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"

Fetching 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"

Subscribing 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"}