The process took four long stages:
Spoken to HR. This is the general "get to know you" phase, assessing if you are a good fit, which is standard. It's also an opportunity to ask questions for yourself.
Short technical questions. Based on point 3, this is arguably needed, in my opinion. It's also an opportunity to ask questions of the technical person.
Once again, a technical interview for around 1.5 hours.
Take-home assignment. The assignment is quite big, and for people who have to do their usual job, this takes a lot of energy away. You must essentially dedicate time after work to do so, which means you don't have much energy for correct decision-making here.
2-hour-long architecture discussion. This does make sense for a senior position.
You could just have more in-depth stages 2 and 3, and then skip to stage 5. Stage 4 is long and tiresome. It does not add any filtering; you could ask questions related to it during stages 2-3 combined.
In combination, this took around a month from application to getting an offer. The process is not smooth and seems a bit odd in places, repetitive, and long.
Most likely, you will get a generous offer if you are good, but expect it to take a while. I would recommend having a parallel interview process running on the side.
The people you interview with are really positive and nice. From this point, I got a good sense of the culture in place.
What architecture would you have in place for your home assignment?
The following metrics were computed from 19 interview experiences for the Checkout.com Senior Software Engineer role in London, United Kingdom.
Checkout.com's interview process for their Senior Software Engineer roles in London, the United Kingdom is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having negative feelings for Checkout.com's Senior Software Engineer interview process in London, United Kingdom.