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Ably FAQs
Channels
Account billing and packages
Packages & Pricing
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
REST API and client libraries
Usage
Common issues
Ably error codes
General
Client errors
Server errors
Integration Errors
Connection Errors
Channel Errors
Other
Spaces errors
Control API 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
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
Can I see messages sent by Channel or ClientID?
Messages
Common misconceptions around Ably History
What is the maximum message size?
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?
Can I store messages on specific channels?
Reliable message ordering for connected clients
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?
How long are messages stored for?
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?
How does delta compression help?
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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?
How do I subscribe or unsubscribe for messages on channels?
Does an attached channel receive messages even if subscribe has not been called?
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Presence
How can I see which channels are currently active?
Why don't presence members leave as soon as I close a tab?
Can I use webhooks or other rules to maintain an external copy of the presence set of a channel or channels?
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 change my connection's clientId after connecting?
What happens to the presence status of a client that abruptly disconnects?
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 names of channel rules / namespaces?
What restrictions are there on channel names?
Are channel names and channel namespaces case-sensitive?
What is a channel namespace and how can I use them?
General
How to limit user numbers in channels/send private or direct messages
What does it mean if I see 'Channel Region Inactive' in my logs on the Dev Console?
What are Channel Mode Flags and how do I use them?
How are channels opened and closed?
History
Can I make a History Call to several Channels Simultaneously?
Occupancy
Can I still use occupancy if the library I am using doesn't yet support channel parameters?