Apollo.io Senior Backend Engineer Interview Experience | Rejected

I interviewed for a Senior Backend Engineer position at Apollo.io in September 2026. With over 7 years of experience.

Exploratory Call with the Engineering Manager

The initial conversation covered my previous projects, experience working with systems at scale, and approach to AI-driven coding. The engineering manager also introduced the team and discussed its work.

Round 1: AI-Assisted Coding

The main technical round involved fixing three issues in a large, poorly written codebase within 90 minutes.

The project ran inside Docker and resembled a Stack Overflow-style question-and-answer platform. Its frontend was served directly by a backend application written in Go.

AI tool constraints: Only mid-tier models, such as Claude Sonnet, were permitted, Claude Opus was not allowed.

Approach and Challenges

I investigated the reported issues, examined the relevant code, identified the root causes, and asked Claude to implement the fixes. However, one of the issues was not resolved correctly.

In retrospect, I felt the expected approach might have involved initializing Claude, providing it with all three issues upfront, allowing it to investigate the codebase independently, and parallelizing the tasks after initialization.

This made the round particularly interesting because it tested not only debugging skills but also how effectively AI tools could be used to navigate an unfamiliar codebase and solve multiple problems within a strict deadline.

Result: Rejected

I did not receive formal feedback, so the rejection was my own assessment rather than a confirmed decision.