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Meta·Machine Learning Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
Apr 2026

Summary

ML system design round at Meta for an MLE role. One meaty question about copyright detection that branched into a bunch of edge cases I wasn't fully ready for.

Questions Asked (1)

Q1

Design a machine learning system to detect whether a user-uploaded image infringes on copyright, including edge cases like collages where only a portion is infringing, images with adversarial text overlays meant to evade detection, and near-duplicate photos of copyrighted works.

System DesignTechnical Trade-offsAdaptability & Ambiguity
Author's notes

The base case felt manageable: perceptual hashing, embedding similarity, maybe a classifier on top.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then propose a multi-stage system that combines detection, localization, and classification. Address each edge case explicitly with tailored techniques, and discuss trade-offs between accuracy, latency, and scalability.

Pro tip: Emphasize the importance of a human-in-the-loop for borderline cases and the need for a feedback mechanism to continuously improve the model, as copyright infringement is nuanced and context-dependent.

1. Clarify Requirements and Constraints

Ask about scale, latency requirements, definition of infringement, and legal considerations. Understand what constitutes a violation and the acceptable false positive/negative rates.

2. Design Core Detection Pipeline

Propose a two-stage approach: first, a fast candidate retrieval using perceptual hashing or embeddings to find potential matches; second, a more precise verification using deep learning models for classification and localization.

3. Handle Edge Cases

For collages, use object detection or segmentation to identify regions and match each part. For adversarial text overlays, employ robust feature extraction and possibly OCR to detect and ignore overlays. For near-duplicates, use metric learning to capture semantic similarity.

4. Address Scalability and Trade-offs

Discuss indexing strategies (e.g., FAISS) for efficient similarity search, model quantization for latency, and the trade-off between precision and recall. Consider distributed processing for large-scale uploads.

5. Evaluate and Iterate

Define metrics (e.g., precision, recall, mAP) and propose an evaluation framework with a labeled dataset. Suggest A/B testing and continuous learning from user reports and appeals.

Key Points to Mention

  • Perceptual hashing (e.g., pHash) and deep metric learning for near-duplicate detection
  • Object detection and segmentation for localizing infringing portions in collages
  • Adversarial robustness techniques, such as adversarial training and input sanitization
  • Scalable similarity search using approximate nearest neighbor (ANN) indexes like FAISS or HNSW
  • Human-in-the-loop review for ambiguous cases and active learning to improve the model
  • Legal and ethical considerations, including fair use and privacy

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.