jupyter-bonjour

A Jupyter Server extension that advertises running servers on the local network via mDNS/Bonjour (zeroconf) service discovery.

Install it, and every Jupyter server on your LAN becomes discoverable — no configuration required. Other machines can find servers automatically using any Bonjour/Avahi/mDNS client.

What gets advertised

Each server registers a _jupyter._tcp.local. service with the following metadata in its DNS TXT record:

Key	Example	Description
version	2.14	Jupyter Server version
auth	token	Authentication method (token, password, or none)
base_url	/	Server base URL
bonjour_version	0.1	This extension's version
ui	lab=4.3,notebook=7.2	Enabled UI frontends
srvxtn	git=0.50,collaboration=0.9	Enabled server extensions
labxtn	@jupyterlab/toc=6.0	JupyterLab frontend extensions

Extension names are shortened for brevity (jupyter_server_ and jupyterlab_ prefixes are stripped), and version strings are compacted (4.0.0 becomes 4).

Credential-like keys (token, password, secret, api_key) are always rejected to prevent accidental leakage onto the network.

Installation

pip install jupyter-bonjour

The extension is auto-enabled on install. Just start Jupyter as usual:

jupyter lab

Your server is now discoverable on the local network.

Configuration

All settings are optional. Add them to jupyter_server_config.py if needed:

c.BonjourExtensionApp.enabled = True                  # set False to disable
c.BonjourExtensionApp.service_name = "My Lab Server"   # custom mDNS name
c.BonjourExtensionApp.interfaces = {"192.168.1.100"}   # restrict to specific IPs
c.BonjourExtensionApp.extra_properties = {              # custom TXT record entries
    "room": "301",
    "owner": "rj",
}

By default the service name is Jupyter on <hostname>:<port> and all non-loopback interfaces are advertised.

Discovering servers

Command line

On macOS:

dns-sd -B _jupyter._tcp local.

On Linux (with Avahi):

avahi-browse -r _jupyter._tcp

Python

from zeroconf import ServiceBrowser, Zeroconf

def on_service_state_change(zeroconf, service_type, name, state_change):
    if state_change.name == "Added":
        info = zeroconf.get_service_info(service_type, name)
        if info:
            addrs = [addr for addr in info.parsed_addresses()]
            port = info.port
            props = {k.decode(): v.decode() for k, v in info.properties.items()}
            print(f"{name} @ {addrs[0]}:{port}  auth={props.get('auth')}")

zc = Zeroconf()
browser = ServiceBrowser(zc, "_jupyter._tcp.local.", handlers=[on_service_state_change])
input("Listening... press Enter to exit\n")
zc.close()

Use cases

• Labs and classrooms — students and instructors can discover each other's servers without exchanging URLs
• Headless machines — find a Jupyter server running on a Raspberry Pi or remote workstation without remembering its IP
• Multi-server setups — see all Jupyter instances on the network at a glance
• Custom tooling — build dashboards or launchers that auto-discover Jupyter services

Requirements

• Python 3.10+
• Jupyter Server 2.0+

License

BSD-3-Clause