Ably has been designed from the ground up so that we can legitimately offer a 100% uptime SLA guarantee to our customers. Uniquely we are able to offer this guarantee because:
- Our infrastructure is spread over 14+ isolated data centres and 6 regions. Each data centre can operate in isolation if necessary should there be network issues outside of our control.
- Every active channel in the real-time system has a primary & secondary co-ordinator across two data centres in the same region and at least one primary server in a geographically separate region. This means at any point in time there are at least 3 copies of the system state and data that can be recovered should any server or region go down.
- All account state, authentication keys and tokens, and statistics are are replicated at least 6 times across 6 data centres and 3 regions.
- All persisted messages are replicated at least 3 times in at least 2 data centres across at least 2 regions.
- We use DNS latency based routing and health checks to ensure that clients are automatically connected to the local available data centre. All DNS has a TTL of 60 seconds so a data centre becoming unavailable will within a minute have traffic routed to one of our other 21+ data centres.
- Our client libraries provide an additional level of DNS redundancy across two registries and domains. If our DNS latency based routing, or even our entire ably.io domain becomes unavailable, the client libraries will find a suitable data centre available on our backup domain ably-realtime.com.
Whilst we sincerely aim to achieve 100% uptime and we do guarantee that in our SLA, it is possible we may not achieve this because we are dependent on numerous 3rd party network services. We will however always keep our service status page up to date with any incidents, we'll always do our best around the clock to fix and remedy against any issues that may arise, and we'll always be honest about our actual uptime.
Added to this, should we fail to meet our 100% uptime guarantee, then every customer will be entitled to a refund based on the amount of down time and your service fee for the month.