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Help Center
Channels
Account billing and packages
Packages & Pricing
Enterprise packages
Charges
Business packages
SLA & Uptime Guarantees
General
FAQ
Getting Started
Contacting us
Realtime API and client libraries
Platform support
Connections
Common issues
Authentication
Troubleshooting
Device support
Development tools
Channels
Messages
Subscribing and publishing
Presence
Namespaces and naming
REST API and client libraries
Usage
Common issues
Ably error codes
Client errors
Server errors
Account and app setup and configuration
Accounts and apps
Keys and tokens
User management
Ably architecture, transports, and security
Transports and connections
Security
Protocol support and protocol adapters
Data centres
Ably architecture design
Performance and Redundancy
Redundancy & reliability
Performance
Push and Smart Notification
Setup
Common questions
Troubleshooting
Reactor Queues, Events and Firehose
Reactor Events, Webhooks and Functions
Reactor Message Queues
Reactor Firehose
Migrating to Ably from an existing service
Migrating from PubNub
Migrating from Realtime.co
Migrating from Pusher
Migrating from Socket.io
API Streamer
General
Channels
Details on channel functionality, limits, and best practices
Messages
Is it possible to check if a specific message has been delivered to a device?
Client-specified message ID restrictions for multiple messages published atomically
What is Idempotent Publishing?
Can I delete messages which have been persisted through the history API?
Am I able to check who has read published messages?
Can I send media stream through Ably?
Can I store my messages for longer?
How synchronized / up to date is channel history between datacenters / regions?
Can messages be consumed using a more traditional streaming API akin to Kafka or SSE?
How do I enable history? My messages are not being stored for longer than a few minutes.
Can I be notified over HTTP when a channel is created or closed?
Can a published message be pushed to a mobile device using Mobile Push Notifications (GCM or APN)?
Do you binary encode your messages for greater efficiency?
Can I store messages on specific channels?
Can I send messages between clients without using channels?
Are messages recovered if my connection drops?
Reliable message ordering for connected clients
What is the maximum message size?
Is it possible to prevent messages published being echoed back to the publishing client?
How long are messages stored for?
Is it possible to check if a specific message has been delivered to a device?
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Subscribing and publishing
Is there a maximum number of channels per connection?
Does an attached channel receive messages even if subscribe has not been called?
How do I subscribe or unsubscribe for messages on channels?
Can I attach and subscribe to channels using wildcards?
Presence
Can I change my connection's clientId after connecting?
Can I use webhooks or other rules to maintain an external copy of the presence set of a channel or channels?
What happens to the presence status of a client that abruptly disconnects?
How can I implement presence subscriptions efficiently, in terms of limits?
How can I see which channels are currently active?
I don't understand why I see so many presence messages in my stats.
Can I change the length of the presence timeout?
Can a single user be present multiple times on the same channel?
What happens if I exceed the number of members present on a channel?
Why don't presence members leave as soon as I close a tab?
Can I be notified over HTTP when someone enters or leaves a channel?
Why do you have a limit on the number of members present on a channel?
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Namespaces and naming
What restrictions exist for the name field of a channel namespaces?
What restrictions are there on channel names?
What is a channel namespace and how can I use them?
Are channel names and channel namespaces case-sensitive?