Tell me about a time you disagreed with a colleague Interview Question for Apple

Tell me about a time you disagreed with a colleague

As a Senior Software Engineer at Google, I've often found myself in situations where differing opinions arise. One particular instance stands out regarding the implementation of a new feature for Google Maps' real-time traffic updates.

Situation

Our team was tasked with improving the accuracy of traffic predictions by incorporating real-time data from third-party sources, specifically Waze. The initial proposal, championed by a more junior engineer, involved directly integrating Waze's API into our existing system. This seemed like a quick and easy solution on the surface.

Task

My responsibility was to ensure the long-term scalability and stability of the traffic prediction system. This included evaluating proposed architectural changes and providing feedback.

Action

I disagreed with the proposed direct integration approach. While it offered a short-term gain in development speed, I believed it had significant drawbacks regarding maintainability, scalability, and vendor lock-in. My concerns were:

Maintainability: Directly tying our system to Waze's API meant we'd be highly dependent on their API changes and uptime. Any modification on their end could potentially break our system.
Scalability: Waze's API might not scale effectively to handle the massive query volume generated by Google Maps users.
Vendor Lock-in: Becoming heavily reliant on a single third-party vendor made it difficult to switch to alternative data sources in the future.

Instead, I proposed an alternative approach: creating an abstraction layer. This layer would act as an intermediary between our system and any external data source, including Waze. This abstraction layer would:

Standardize the data format: Transform data from different sources into a consistent format, simplifying integration and data processing.
Provide fault tolerance: Implement retries and fallback mechanisms to handle API failures from external sources.
Enable vendor independence: Allow us to easily switch between different data providers without significant code changes.

I presented my concerns and proposed solution during a team meeting, backing it up with data on potential cost savings associated with avoiding vendor lock-in, and improved system resilience.

Initially, the junior engineer was hesitant, as my proposal required more upfront development effort. He argued for the simplicity and speed of the direct integration approach.

To address his concerns, I worked with him to create a detailed comparison of the two approaches, outlining the pros and cons of each, and estimating the development time for both. I also highlighted the long-term benefits of my approach, emphasizing the reduced risk of system failures and the increased flexibility it offered.

Result

After careful consideration, and further discussion with the team lead, my proposed solution was adopted. We implemented the abstraction layer, which proved to be a robust and flexible solution. We were able to successfully integrate Waze's data, and the abstraction layer allowed us to easily incorporate data from other sources later on.

Furthermore, a few months after the initial implementation, Waze made a significant change to their API. Because of the abstraction layer, the impact on our system was minimal, requiring only a few hours of work to adapt to the new API. This validated the decision to invest in the abstraction layer and highlighted the importance of considering long-term maintainability and scalability.

This experience taught me the importance of clearly articulating my concerns, backing them up with data, and working collaboratively to find the best solution, even when faced with initial resistance. It also reinforced the value of thoughtful design and planning in software engineering, even when it requires more upfront effort.