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Ably FAQs
Channels
Account billing and packages
Packages & Pricing
Enterprise packages
Charges
Business packages
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
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
Reactor Errors
Connection Errors
Channel Errors
Other
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
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
Connections
Latest advice
Billing & Payment
Channels
Details on channel functionality, limits, and best practices
Can I see messages sent by Channel or ClientID?
Messages
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?
What is the maximum message size?
Can a published message be pushed to a mobile device using Mobile Push Notifications (GCM or APN)?
How do I send emojis over Ably
Reliable message ordering for connected clients
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 store my messages for longer?
Can I store messages on specific channels?
Can I send messages between clients without using channels?
Can I send media stream through Ably?
Can I delete messages which have been persisted through the history API?
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?
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 messages be consumed using a more traditional streaming API akin to Kafka or SSE?
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?
How do I subscribe or unsubscribe for messages on channels?
Does an attached channel receive messages even if subscribe has not been called?
Can I attach and subscribe to channels using wildcards?
Presence
What happens if I exceed the number of members present on a channel?
Can I use webhooks or other rules to maintain an external copy of the presence set of a channel or channels?
Can I change the length of the presence timeout?
How can I see which channels are currently active?
How can I implement presence subscriptions efficiently, in terms of limits?
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?
Can I change my connection's clientId after connecting?
What happens to the presence status of a client that abruptly disconnects?
I don't understand why I see so many presence messages in my stats.
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?
What restrictions exist for the name field of a channel namespaces?
Are channel names and channel namespaces case-sensitive?
What restrictions are there on channel names?
General
How to limit user numbers in channels/send private 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?