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Channels

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?