About try.desync.com

try.desync.com gives you a web-based shell on a dynamically-allocated instance.

There are some differences from a normal instance, though. Specifically:

The host is a VM.
Network connections are limited in terms of concurrency.
Network traffic is limited in aggregate throughput.
The Basis image is a customized FreeBSD that includes some tools like curl and mtr.
SSH host keys are pre-generated (and thus, shared) to reduce startup time.
The broker's SSH keys are preloaded, rather than having to wait for desync-provision to run.

The session broker (Zuul) places some limits on number of concurrent sessions beyond the normal placement limits imposed by the API, mostly by client ASN and/or subnet. The idea is to prevent one person from hogging all the sessions, which might also indicate that some mischief is afoot.