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Ably FAQs
Channels
Account billing and packages
Packages & Pricing
Limits
Committed Use
Charges
SLA & Uptime Guarantees
General
FAQ
Getting Started
Contacting us
Architectural Advice
Realtime API and client libraries
Platform support
Connections
Common issues
Authentication
Troubleshooting
Device support
Development tools
SDK
Channels
Messages
Subscribing and publishing
Presence
Namespaces and naming
General
History
Occupancy
Metadata and statistics
REST API and client libraries
Usage
Common issues
Ably error codes
General
Client errors
Server errors
Integration Errors
Connection Errors
Channel Errors
Spaces errors
Control API errors
Other
Push notification errors
Account and app setup and configuration
Accounts and apps
Keys and tokens
User management
Account maintenance
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 Notifications
Setup
Common questions
Troubleshooting
Integrations
Events, Webhooks and Functions
Message Queues
Firehose
Datadog
Migrating to Ably from an existing service
Migrating from PubNub
Migrating from Pusher
Migrating from Socket.io
Channels
Details on channel functionality, limits, and best practices
Messages
Can I delete messages which have been persisted through the history API?
Is it possible to check if a specific message has been delivered to a device?
Reliable message ordering for connected clients
Can a published message be pushed to a mobile device using Mobile Push Notifications (GCM or APN)?
How do I send emojis over Ably
Is it possible to prevent messages published being echoed back to the publishing client?
Do you binary encode your messages for greater efficiency?
Can I send messages between clients without using channels?
Can I be notified over HTTP when a channel is created or closed?
Are messages recovered if my connection drops?
Am I able to check who has read published messages?
Client-specified message ID restrictions for multiple messages published atomically
What is Idempotent Publishing?
Can I store messages on specific channels?
I'm not receiving messages, how do I debug that?
Can I see messages sent by Channel or ClientID?
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Subscribing and publishing
Subscription filters
Is there a maximum number of channels per connection?
Can I attach and subscribe to channels using wildcards?
Does an attached channel receive messages even if subscribe has not been called?
Private/direct messages between users and group chat
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Presence
Can I use webhooks or other rules to maintain an external copy of the presence set of a channel or channels?
Why don't presence members leave as soon as I close a tab?
Can a single user be present multiple times on the same channel?
I don't understand why I see so many presence messages in my stats.
What happens if I exceed the number of members present on a channel?
Can I change the length of the presence timeout?
How can I implement presence subscriptions efficiently, in terms of limits?
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 is a channel namespace and how can I use them?
Are there restrictions on channel names?
General
How are channels opened and closed?
How to limit user numbers in channels
What does it mean if I see 'Channel Region Inactive' in my logs on the Dev Console?
History
Can I make a History Call to several Channels Simultaneously?
Common misconceptions around Ably History
How do I enable history? My messages are not being stored for longer than a few minutes.
How synchronized / up to date is channel history between datacenters / regions?
Occupancy
Can I still use occupancy if the library I am using doesn't yet support channel parameters?
Metadata and statistics
How can I see which channels are currently active?