Comparing the Three Use Cases¶
Overview Matrix¶
| Aspect | Product Search | Support Tickets | Recommendations |
|---|---|---|---|
| Frequency | Per user query (1-5/user/month) | Per issue (5/user/year) | Often (multiple/session) |
| Latency requirement | <100ms p95 | <2s | <500ms |
| Cost per call | $0.001 | $0.001 | $0.001 |
| Effective cost | $0.0006 (40% cache) | $0.0001 (90% simple) | $0.0004 (60% cache) |
| Complexity | Ranking | Text generation | Ranking + explanation |
| Quality impact | Revenue +15% | Cost -90% | Revenue +15% |
| Risk if AI fails | Mediocre results | Escalated to human | Falls back to ML |
| Best for | E-commerce | Support | Any marketplace |
Cost-Benefit Comparison¶
Annual Impact (1M users, 10M queries served)¶
Product Search
Effective cost: 10M * $0.0006 = $6K
Incremental revenue (15% * $50 AOV): +$7.5M
ROI: 1,250,000x
Support Tickets
Small query volume but huge per-ticket savings
Effective cost: 100K tickets * $0.0001 = $10
Cost savings (92% reduction * $6.67/ticket): +$617K
ROI: 61,700x
Recommendations
Effective cost: 10M * $0.0004 = $4K
Incremental revenue (15% * $50 AOV): +$7.5M
ROI: 1,875,000x
Implementation Complexity¶
Simplicity Ranking (simplest to hardest):
1. Support Tickets (★★)
- Input: User's issue (text)
- Output: Helpful response (text)
- Validation: Easy (just check it's relevant)
- Error handling: Simple (escalate if bad)
2. Product Search (★★★)
- Input: Query + product catalog
- Output: Ranked list
- Validation: Must check accuracy
- Error handling: Fallback ranking
3. Recommendations (★★★★)
- Input: User profile + huge catalog
- Output: Personalized ranked list
- Validation: Must align with business rules
- Error handling: Fallback to ML model
When to Use Each¶
Product Search¶
Good for: - E-commerce sites - Dense product catalogs (>10K items) - Users searching with natural language - Sites with high AOV
Avoid: - Small catalogs (<1K items) - Users click through lists anyway - Keyword search is good enough
Support Tickets¶
Good for: - High support volume - Many FAQ-style questions - Need immediate customer response - Want to reduce support costs
Avoid: - Complex support (needs specialized agent) - Legal/compliance heavy - Complaints that need empathy (LLM can't always deliver)
Recommendations¶
Good for: - Marketplaces (Amazon-like) - Users with diverse preferences - Want to increase AOV - Have user history/profile
Avoid: - Cold-start users (no profile) - Simple stores (<100 products) - Algorithmic ranking works well
Decision Tree¶
Should I use AI for this feature?
START
↓
Does it involve
ranking/ordering?
│
├──Yes→ Use AI? (Search or Recommendations)
└──No
↓
Is it generating
customer-facing text?
│
├──Yes→ Use AI (Support Tickets)
└──No
↓
Probably don't use AI
(simpler solution exists)
Learning Path¶
Start with Support Tickets: - Simplest to implement - Easy to demonstrate value - Quick wins build confidence
Then Product Search: - More complex ranking - Better ROI on e-commerce - Good for interview discussion
Then Recommendations: - Most complex - Highest ROI - Demonstrates full system design
Interview Prompt¶
"Design an AI system for a new use case of your choice."
Suggested: Product Search (middle complexity)
Structure: 1. Explain the problem (traditional search is generic) 2. Show AI solution (LLM-based ranking) 3. Discuss architecture (service layer) 4. Analyze cost-benefit 5. Handle edge cases (cache, fallback, errors) 6. Monitor in production