---
title: 'REST vs GraphQL vs gRPC: Which API Wins in System Design Interviews?'
source: 'https://youtube.com/watch?v=Q3f5jmIwN3Y'
video_id: 'Q3f5jmIwN3Y'
date: 2026-08-04
duration_sec: 73
---

# REST vs GraphQL vs gRPC: Which API Wins in System Design Interviews?

> Source: [REST vs GraphQL vs gRPC: Which API Wins in System Design Interviews?](https://youtube.com/watch?v=Q3f5jmIwN3Y)

## Summary

The video explains the three main API protocols—REST, GraphQL, and gRPC—and their appropriate use cases in system design interviews. It emphasizes that each protocol has a specific job and choosing the right one is crucial for interview success.

### Key Points

- **REST for CRUD** [00:02] — REST is the default choice for CRUD operations, using resources as URLs and verbs as actions. It rides on HTTP, inheriting caching, retries, and status codes.
- **GraphQL for flexible data** [00:15] — GraphQL is ideal for product UIs needing flexible, nested data. Clients query exactly the shape of data they want, avoiding over-fetching or under-fetching common with REST.
- **gRPC for internal services** [00:28] — gRPC is for internal service-to-service calls requiring speed and strict contracts. It uses binary over HTTP/2, generates typed clients, and supports streaming and multiplexing.
- **Performance comparison** [00:43] — gRPC is significantly faster than JSON over REST for millions of calls between services, making it the choice for high-throughput inter-service communication.
- **Interview guidance** [00:55] — In system design interviews, choose REST for CRUD, GraphQL for flexible client data needs, and gRPC for inter-service communication at scale.

### Conclusion

Understanding when to use REST, GraphQL, and gRPC is essential for system design interviews. Each protocol serves a distinct purpose, and selecting the right one demonstrates architectural thinking.

## Transcript

your system design interview, you might be in trouble. There's actually three protocols that are worth knowing, and each one has a job. REST is certainly your default choice for CRUD operations. Resources as URLs, verbs as actions, and
it rides on top of HTTP, so you inherit caching, retries, and status codes for free. But then there's GraphQL, which is great for product UIs that need flexible, nested data. Clients can write a query describing exactly the shape of
the data that they want, and the server returns that, no more or no less. So you like there might be with REST. Lastly, there's gRPC. It's for internal service-to-service calls where you want speed and strict contracts. Binary over
HTTP/2, protocol schemas generate typed clients in every language, and you get streaming and multiplexing built in. It's significantly faster than JSON over REST when you're making millions of calls between services. So in your
for GraphQL when the client needs flexible or deeply nested data, and drop in gRPC when you're designing inter-service communication at scale. either over on YouTube or on hellointerview.com.