Glovo was recruiting for "senior" engineers but they work with levels. Here it was about L2 and L3. So even if you feel you did a poor job, you might get away with a L2 offer instead of a L3.
All in all, 6 online interviews. If you have a lot of free time you can squeeze it in less than a month. Each step is well explained by the recruiter and pdf files.
1. Screening with a recruiter
Don't overlook this first one as there is a mix of standard and technical questions, such as :
why Glovo, tell more about Glovo, your experiences...
technical questions about structures, sorting algorithm complexity, Design pattern, Rest, MS vs monolith architecture...
2. Algorithm coding interview
3 exercises to be done in less than 1h30. They are not really complex, but if you are not used to that kind of thing, your brain might completely freeze (mine did that). If you have some time, use pramp by exponent or any other website doing mocking interviews, so that you keep your stress level under control. You can also complete your preparation with the "cracking the coding interview book" (or something similar) but I am not really convinced by the ROI of reading the whole thing. They are more interested by your thought process and will step in if you are drifting away. Explain what you are doing and it should be fine (and pay attention to your tests: find more edge cases)
3. Technical questions interview
This one is extremely well explained in the resource given by the recruiter. Expect technical and follow-up questions.
4. Culture fit interview
Keep in mind the main keywords of Glovo when you speak about your experience and everything should be fine.
5. Application design interview
2 parts: domain model design and REST API design. If you are used to anemic domain models like me, brush a bit OOP (come up with correct classes and more importantly their methods). I had a question that is already listed in glassdoor. Word of advice: if you can do a mock interview using pramp, do it.
6. System design interview
I was expecting something very difficult such as what you can find in algoexpert.io website, but this one was simpler. The question I had is already listed on Glassdoor. Once again, if you are not used to system design interview, do mocking interviews beforehand.
4, 5 and 6 are scheduled at the same time by the coordinator, and can be in another order.
I rated "difficult" because I did not practice application & system design interviews, but if you are used to it, the overall process is not really difficult for a seasoned developer.