Explain RAG vs Fine-tuning.

RAG vs fine-tuning compares two ways of adapting AI models: Retrieval-Augmented Generation (RAG) connects models to external data in real time, while fine-tuning retrains the model to internalize new knowledge.

When to Use

RAG is best when information changes quickly (e.g., news, product catalogs) or is too large to store inside a model. Fine-tuning works well when the domain is stable, and responses must follow a specific style or format.

Example

A customer support bot may use RAG to fetch answers from updated documentation, while a fine-tuned model ensures responses always match the company’s tone.

For deeper mastery, explore Grokking System Design Fundamentals, Grokking the Coding Interview, or practice through Mock Interviews with ex-FAANG engineers.

Why Is It Important

Choosing the right approach determines whether your AI is current and flexible (RAG) or specialized and efficient (fine-tuning).

Interview Tips

In interviews, define both clearly, give a practical use case, compare pros/cons, and highlight that combining them often produces the strongest results.

Trade-offs

RAG keeps responses fresh and reduces hallucinations but adds latency and retrieval complexity. Fine-tuning makes inference fast and domain-specific but requires costly retraining and risks outdated knowledge.

Pitfalls

Avoid assuming fine-tuned models will “know everything” or that RAG alone can fix model weaknesses. A hybrid often works best.

TAGS
System Design Interview
System Design Fundamentals
CONTRIBUTOR
Design Gurus Team
-

GET YOUR FREE

Coding Questions Catalog

Design Gurus Newsletter - Latest from our Blog
Boost your coding skills with our essential coding questions catalog.
Take a step towards a better tech career now!
Explore Answers
Google System Design Interview Questions (And Answers)
Prepare for Google system design interviews with top 10 real-world questions and answers. Learn key concepts, best practices, and structured approaches to ace your interview.
What is called design pattern?
What is step wise interview method?
How to clear a Salesforce interview?
How to crack an online technical interview?
What Is Cold Start and How to Reduce It?
Learn what cold start is, why it matters in system design, practical strategies to reduce it, interview tips, trade-offs, and pitfalls. Perfect for coding and system design interview prep.
Related Courses
Course image
Grokking the Coding Interview: Patterns for Coding Questions
Grokking the Coding Interview Patterns in Java, Python, JS, C++, C#, and Go. The most comprehensive course with 476 Lessons.
4.6
Discounted price for Your Region

$197

Course image
Grokking Modern AI Fundamentals
Master the fundamentals of AI today to lead the tech revolution of tomorrow.
3.9
Discounted price for Your Region

$78

Course image
Grokking Data Structures & Algorithms for Coding Interviews
Unlock Coding Interview Success: Dive Deep into Data Structures and Algorithms.
4
Discounted price for Your Region

$78

Image
One-Stop Portal For Tech Interviews.
Copyright © 2026 Design Gurus, LLC. All rights reserved.