The hiring process at Zeller takes an average of 10 days when considering 2 user submitted interviews across all job titles. Candidates applying for React Native Engineer had the quickest hiring process (on average 5 days), whereas SDE 3 roles had the slowest hiring process (on average 14 days).
I applied online. The process took 2 weeks. I interviewed at Zeller (Bengaluru) in Nov 2025
Interview
The Interview Process included three rounds. First round included project discussion, Node.js basics (event loop, architecture), and DSA Problems. 2nd Round Again node.js output-based questions, how to handle race conditions, write code to implement batch process. I messed up on the 2nd round
Interview questions [1]
Question 1
First Round: Explain the event loop, Architecutre of Nodejs
Qus 1: Evaluate the sum of the nested array [1, 2, 3, [1, 2, 3, [1, 2, 3]]];
Qus 2: let a = [1,1,1,2,2,2,3,3,3,3,4,4,4,5,5,6,6]
// output = [1,2,3,4,5,6,1,1,2,2,3,3,3,4,4,5,6]
// swap all the unique elements at the beginning of the array
Second Round:
Custom promise.all with batch processing.
I applied online. The process took 5 days. I interviewed at Zeller (Noida) in Sept 2024
Interview
The first round involves completing a coding challenge.
The coding challenge can be found at the following link and includes instructions in the README file. Once you complete the challenge, please send it back to me (GitHub repo preferred), and we'll schedule it for a follow-up interview after a successful review. During this Interview, amongst other questions, we might ask you to modify the code and logic in a live coding session.
Interview questions [1]
Question 1
Zeller React Native Code Challenge
1. Goal
Your goal is to build a React Native app that displays and filters a list of users. Designs for the application are provided, and the user list and filtering should be achieved by connecting to a provided Graphql endpoint. We are most interested in the way you structure your code, your use of typescript, and your approach to testing.
2. Requirements
Your app should display a list of users that are returned by the listZellerCustomers query. The graphql schema you will need, and the connection details can be found in aws-exports.js and schema.gql
Your app should have a list of selectable user types that include Admin and Manager. Selecting a user type should perform a query against listZellerCustomers using that user type as a filter.
Your app should run on IOS or android
Designs for the user feature are provided below (4). If you wish to add navigation, navigation bars, drawers etc, feel free to do so.
Tests are VERY important
Make sure to have clean and readable source code
3. Bonus Points
These features are absolutely not required, however if you finish your project eary and wish to continue, here are some ideas
Implement App navigation with a second, empty homescreen
Implemenent a text search box that filters users by name
Implement a pull to refresh on the list