Our free package is free-forever. It's designed for low volume production use and will support you for as long as it fits your usage requirements. Free packages are limited to a total of 3m messages per month, 100 peak connections and 100 peak channels. Any requests sent to the Ably platform that exceed this threshold will be automatically rejected, and you will be notified. We provide best-effort support only. You can upgrade to a paid plan in your account dashboard at any time.

We'll let you know via email if it looks like you're going to exceed your reserved monthly package allowance, so you'll always have ample time to act if needed.

If you do need more capacity than your package allows, there are two options: upgrade your monthly package or pay overage fees for every message, connection, and channel over your allocated. Overages are charged at a flat rate of $2.50 p/million messages and $20.00 p/thousand connections or channels. Customers on enterprise packages benefit from volume discounts.

If you've outgrown the needs of your current package, it will always be more cost effective to upgrade your package instead of paying overages.

You're able to burst your monthly quota to 2.5x as Self-service. If you exceed your prepaid quota, you'll be charged overage fees at the month end at a rate of $2.50 per million messages, $20.00 for every 1,000 peak connections and $20.00 for every 1,000 peak channels. We always send you a warning when you’re nearing your prepaid quota, when you’ve exceeded your prepaid quota, and when you’re nearing your hard limit of 2.5x or 5x your prepaid quota. If you’re an Enterprise customer, we work with you to ensure you never reach your hard limits by both provisioning excess burstable capacity and actively monitoring your account usage throughout the month.

We provide realtime metrics in your account dashboard that include the total number of messages, peak connections, peak channels, total bandwidth, average message size. You can also access your stats programmatically via our API.

Every message published or received is counted towards your message allocation. If you publish one message to a single channel with 10 subscribers, this will be counted as 11 messages (1 published + 10 received). Additionally:

• If you're using presence, then every time a user enters or leaves presence, or updates their presence data, that is counted as a message published by them (so as above, for a 10 person channel, it will count as 11 messages).
• If you choose to persist your messages, every message persisted or retrieved from your history is counted towards your message allocation.
• Monthly messages, from a billing perspective, are calculated based on the greater of the total bandwidth or total messages published and received. While the max message size for free accounts is 16KiB by default, and 64KiB for Self-service accounts, the average Ably message size by default is 2KiB. If your average message size is, for example, 16KiB, Ably would count each message as 8 messages of 2KiB.
• Event filtering on a channel such as subscribe('event_name', function(){...}) is done client-side. As a result, all messages published on a channel are still sent to the client and so will count towards your allocation.
• Messages published by a realtime connection are echoed back to the publisher unless ClientOptions#echoMessages is set to false. So by default, every message published by a realtime connection will count as two messages.

Peak connections are the maximum total number of client devices devices (browser, mobile, server, etc.) that have connections to your account at any time in a calendar month. A single connection can be attached to many channels, using a number of our supported transports (such as WebSockets or HTTP), and this will still only count as one connection.

Peak channels are the maximum total number of channels active in your account at any time in a calendar month. A channel becomes active when a client attaches to a channel, or when a client publishes to a channel. A channel will remain active for as long as a connected client remains attached to that channel, or for up to two minutes after the last activity on a channel such as a publish event or a client detaching from that channel.

Yes. If you upgrade in the middle of your billing period then we calculate your new allocation of messages reserved pro-rata to the time left in that month. However, if you downgrade, the new reserved number of messages and subscription amount will come into effect the following month.

Only enterprise customers can customize their package and limits to suit their needs. Enterprise customers also benefit from things such as enterprise-only features, more integrations, increased quality of service, and access to engineers during on-boarding. Get in touch to speak with someone about a custom enterprise package.

We don't currently support a self-hosted version of Ably because of the immense complexity that is required in running a highly-available, low-latency global realtime service. If you're concerned with security or need to transmit highly sensitive data, then we recommend that you consider using the symmetric encryption feature of our client library SDKs. This will ensure that no one without your private key, including Ably, can see the content of any messages transmitted using our service.

That said, for enterprise customers we're exploring offering CI integration with services like Docker. If you're exploring an enterprise package and feel you need to install Ably on your servers, please get in touch.

Ably is a registered Data Controller in the UK. Please see our data protection policy for more info.

In regards to Ably's HIPAA compliance, please see our Ably U.S. HIPAA (Health Insurance Portability and Accountability Act) Statement.

Yes. For Enterprise customers we can constrain traffic to the US or EU. Find out more about EU-only storage and US-only storage.