Build any realtime experience using Ably’s Pub/Sub Python SDK.
Ably Pub/Sub provides flexible APIs that deliver features such as pub-sub messaging, message history, presence, and push notifications. Utilizing Ably’s realtime messaging platform, applications benefit from its highly performant, reliable, and scalable infrastructure.
Find out more:
Everything you need to get started with Ably:
Ably aims to support a wide range of platforms. If you experience any compatibility issues, open an issue in the repository or contact Ably support.
The following platforms are supported:
| Platform | Support |
|---|---|
| Python | Python 3.7+ through 3.14 |
Note
This SDK works across all major operating platforms (Linux, macOS, Windows) as long as Python 3.7+ is available.
Important
SDK versions < 2.0.0 are deprecated.
To get started with your project, install the package:
pip install ably-pubsub-serverThe package installs into ably.pubsub, and the whole public API is reached
through ably.pubsub.server:
from ably.pubsub.server import create_http_client, create_realtime_clientClients are built by these factories rather than by constructing a class, so
that the package a client comes from names the side your application runs on.
Annotate against the prototypes they return, PubSubHttpClient and
PubSubRealtimeClient.
The synchronous, HTTP-only flavour lives alongside it:
from ably.pubsub.server.sync import create_http_clientBoth ably and ably.pubsub are namespace packages
shared with the other ably-* distributions, so neither exports anything
itself — always import from ably.pubsub.server.
Note
Install Python version 3.8 or greater.
The following code connects to Ably's realtime messaging service, subscribes to a channel to receive messages, and publishes a test message to that same channel.
from ably.pubsub.server import create_realtime_client
# Initialize Ably Realtime client
async with create_realtime_client(key='your-ably-api-key', client_id='me') as realtime_client:
# Wait for connection to be established
await realtime_client.connection.once_async('connected')
print('Connected to Ably')
# Get a reference to the 'test-channel' channel
channel = realtime_client.channels.get('test-channel')
# Subscribe to all messages published to this channel
def on_message(message):
print(f'Received message: {message.data}')
await channel.subscribe(on_message)
# Publish a test message to the channel
await channel.publish('test-event', 'hello world')LiveObjects keeps shared, mutable state on a channel: maps and counters that every client
attached to it reads, updates and subscribes to. The channel needs the object modes, and
channel.object.get() attaches it, waits for the objects to sync, and returns the root map.
Values are read through a typed view of their path — as_live_map(), as_live_counter() or
as_primitive() — and reads are synchronous; writes are awaited.
from ably.pubsub.server import ChannelMode, ChannelOptions, create_realtime_client
from ably.pubsub.server.liveobjects import LiveCounter, LiveMap
async with create_realtime_client(key='your-ably-api-key') as realtime_client:
channel = realtime_client.channels.get(
'my-objects',
ChannelOptions(modes=[ChannelMode.OBJECT_SUBSCRIBE, ChannelMode.OBJECT_PUBLISH]),
)
# Attach, wait for the objects to sync, and get the root map
root = await channel.object.get()
# Create objects by setting them on the root
await root.set('visits', LiveCounter.create(0))
await root.set('profile', LiveMap.create({'name': 'Alice', 'theme': 'dark'}))
# Read through a typed view of the path
visits = root.get('visits').as_live_counter()
print(visits.value()) # 0.0
print(root.at('profile.name').as_primitive().value(str)) # Alice
# Subscribe to changes at a path
def on_change(event):
print(f'{event.object.path()} changed')
subscription = root.get('visits').subscribe(on_change)
# Mutate
await visits.increment(5)
# Batch several writes into a single message
async with root.get('profile').as_live_map().batch() as profile:
profile.set('name', 'Bob')
profile.remove('theme')
subscription.unsubscribe()The CHANGELOG.md contains details of the latest releases for this SDK. You can also view all Ably releases on changelog.ably.com.
Read the CONTRIBUTING.md guidelines to contribute to Ably.
For help or technical support, visit Ably's support page or GitHub Issues for community-reported bugs and discussions.
This SDK currently supports only Ably REST and basic realtime message subscriptions. To access full Ably Realtime features in Python, consider using the MQTT adapter.