The service availability is based on the service type and plan being used.
Single node plans (Hobbyist and Startup) have limited capabilities when the single node fails
Highly available plans (Business and Premium) are resilient to single node failures and in some cases to multiple node failures
Our Hobbyist and Startup plans are serviced by a single Virtual Machine node. This means that if the node fails, the service will be unavailable until a new VM is built. There may be some degree of data loss as it's possible that some of the latest changes to the data haven't been backed up before the failure. It can also take a long time to recover the service back to normal operation as a new VM needs to be created and restored from backups before the service can resume operations. The time to recover depends on the amount of data to restore.
Our Business and Premium plans are very resilient to failures. A single node failure will cause no data loss and the possible downtime will be minimal. In case an acting PostgreSQL or Redis master node fails an up-to-date replica node is automatically promoted to become the new master. This will cause minimal outage to applications as they need to reconnect to the database to access the new master.