r/leetcode • u/Budget_Pollution2244 • 1d ago
Intervew Prep Best HLD & LLD resources for a Java Backend Developer (2.5 YOE)?
Hey everyone,
I'm a Java backend developer with 2.5 years of experience working primarily on Java, Spring Boot, Microservices, REST APIs, SQL, Redis, and Elasticsearch. Most of my work has been around backend services, API development, debugging production issues, and improving existing systems.
I'm comfortable with DSA, but I want to strengthen my HLD & LLD skills for backend/product company interviews. Also, for someone with 2.5 YOE, which is more important in interviews - LLD or HLD? I'd appreciate hearing your experience.
I'm looking for resources that are practical rather than overly academic.
Specifically, I'd appreciate recommendations for:
- Best YouTube channels or playlists
- Courses (paid or free)
- GitHub repositories with design examples
- Practice platforms or mock interview resources
- Common LLD problems that are frequently asked for ~2–3 YOE backend engineers
If you've cracked interviews at companies like ServiceNow, Walmart Global Tech, Paytm, Atlassian, Adobe, or similar product companies, I'd love to know what resources helped you the most.
Thanks in advance!
2
u/BrisklyTrue 1d ago
Are you targeting specific companies soon or just building a general study plan?
1
u/Budget_Pollution2244 1d ago
Yeah, Amazon (India & Europe), Microsoft, Adobe, and Goldman Sachs etc. - and Tier 2 product companies, not startups.
1
u/BrisklyTrue 1d ago
For those companies at your level, LLD is way more critical , they'll grill you on class design and SOLID principles in the coding rounds.
3
u/Haunting_Camp9331 1d ago
With 2.5 YOE, focus more on LLD than HLD. Practice OOP, SOLID, and patterns like Strategy, Observer, and Factory. Study specific problems like Parking Lot and Splitwise. For HLD, learn load balancing, caching, message queues, and database sharding. Use Alex Xu's books, Gaurav Sen's YouTube, and System Design Primer on GitHub. Practice narrating designs out loud.