I was contacted via Linkedin.
The process is quite simple and fast. The first step is a conversation with the recruiter, the second is a coding challenge where you need to record your screen while you're coding, and you need to explain what you're doing. The third step is a technical video recording, where you will receive some questions and you need to explain the concepts they are asking for.
After these three steps, you will receive the final feedback, with a pre-offer, if positive. But they'll try to find clients for ya, only after this pre-offer.
In my case, these clients has never come. Even after 5 months, and even I've being invited to join their network.
The last fullstack labs email email seems a little sad, given there is no expectations to get in touch with clients soon, doing the recession.