I interviewed for a Machine Learning Engineer role at PayPal, starting in December 2024.

The process was long and drawn out. After an initial HR round, there was another HR discussion in March 2025, followed by four more rounds:

• A 1-hour coding interview (data structures and algorithms)
• A behavioral round with the manager (focused on experience and ML)
• A 1-hour system design round
• A final behavioral/technical round with the manager and team

In total, I completed six rounds and felt confident in my performance.

However, despite multiple follow-ups over several weeks, I never received any feedback or update. My emails were seen but ignored, and the job posting disappeared from the portal.

To make things worse, I later received an automated feedback survey while still waiting for a response.

This level of communication—or lack thereof—is extremely unprofessional for a company of PayPal’s scale. Candidates deserve respect and closure, especially after such a lengthy process.

How would you design a scalable machine learning pipeline for real-time predictions?

How would you handle data drift or model decay in production?