I applied online. I interviewed at Vonage (Wrocław) in Mar 2023
Interview
1.Recruiter call 2. Codility coding test with 2 questions 3. Code interview with lead developer, you will be given a coding question and you will write solution and discuss time complexities. How can you make it memory efficient and how can be more performance efficient 4. Technical interview with manager Total process 2-3 weeks.
Interview questions [1]
Question 1
1. Codility codingtest with 2 questions on algorithms 2. Code interview with lead developer on a shared board : method with two int arrays as input that return an array as output which does not have common elements in the given two arrays after you write the solution, what will be the time complexity? 2 times o(n)*o(n). How can we reduce this time comlexity or make it memory efficient? 3. Technical interview with manager : diff between Kafka and rabbit mq, some more questions about kafka how Kafka is scaled. Difference between rational and no sql databases. How relational databases are scaled. Data structure questions. Pseudo code method with a string input returns a string output with the occurrences of duplicates input: abbcccabbbb output: a2b3ca4b
I applied online. The process took 1 week. I interviewed at Vonage (Barcelona) in Oct 2025
Interview
I was rejected after the first interview, a "pair programming". It was run by a manager, and they intended me to code a simple function in Java on a Google Docs. I offered to do it on my local IDE and share my screen which was accepted. I was not given any feedback at all as to why I was rejected.
Interview questions [1]
Question 1
Code a simple function in Java in a Google Docs document.
I applied through a recruiter. I interviewed at Vonage (Bengaluru) in Feb 2024
Interview
Coding plus design discussion
debug the performance of application if latency is becoming high, what all metrics to monitor
Scale application,
metric to monitor
synchronization in java
multithread safe data structures in java
Interview questions [1]
Question 1
Have 2 apis
one to add balance in wallet
second to deduct balance from wallet
one request comes at beginning of day to add balance
multiple frequent requests throughout the day to deduct balance
Which datatype would you take to store balance till 2 decimal places and thread safety
Concurrent datastructures in java vs AtomicReference
Scale it for multiple users
I applied online. The process took 1 day. I interviewed at Vonage in Nov 2023
Interview
After applying online, I had a 20 minutes talk with a recruiter (which I thought was fine, I usually pass this level). He explained about the next steps, but I never heard from them again. Not even a generic rejection email.