Recently interviewed for Staff Software Engineer - Backend at Agoda through their 1-Day Fast Track process. Sharing the experience anonymously since I found the Platform round quite different from a normal system-design interview.

Round 1: Coding & Algorithms (60 min)

Q1: Degree of an Array
https://leetcode.com/problems/degree-of-an-array/

Q2: Disk Space Analyzer
Given an array space[] and window size x:

• Find the minimum available space in every contiguous window of size x
• Return the maximum among those minimum values
  Example:
  x = 2, space = [8, 2, 4, 6]
  window minimums = [2, 2, 4]
  answer = 4

Constraints were large, so an efficient sliding-window approach, combined with Min-heap was required.
Managed to solve both questions before time.

Round 2 — Platform + Code Review (60 min)

This was the more interesting round.
The initial architecture was roughly:

The Search Service calls multiple external vendors, aggregates their results, stores them, and returns the response. Search results remain valid for 1 hour.

Topics we discussed:

• Redis caching with 1-hour TTL
• Cache key around (productId, vendorId)
• Database as a fallback/persistent store
• Separating vendor communication into a dedicated Vendor Service
• Handling many requests arriving together after cache expiry / cache stampede
• Distributed coordination using Redis
• DB indexing around product/vendor lookup
• Authentication and general service responsibilities

The interviewer also wanted to discuss testing, but we were running short on time.

Code Review
I was given Java code implementing the same Search Service.
There was vendor-specific logic similar to:

if (vendor == A) {
    ...
} else if (vendor == B) {
    ...
} else if (vendor == C) {
    ...
}

I suggested extracting this behind a common interface using the Strategy Pattern, with separate vendor implementations.
We also discussed:

• Single Responsibility Principle
• dependency injection
• maintainability/extensibility
• separation of vendor-specific logic
• parallel vendor calls
• general readability/code structure

Outcome

Unfortunately, I was rejected after Round 2, so I didn't proceed to the Architecture and Hiring Manager rounds.

The coding round went well, and I felt I answered most of the Platform/code-review questions reasonably well. My main takeaway is that for a Staff-level Platform round, they may expect you to proactively identify bottlenecks and design issues.

Would be interested to hear from anyone who has interviewed for Agoda Staff/Senior Backend roles.