Upstream: Technical Interviews

DunderLab

In-app purchases

About this app

Upstream is a technical review platform built for software engineers who want to strengthen their engineering knowledge and prepare for more demanding technical challenges.

Instead of teaching programming from scratch, Upstream helps you revisit advanced concepts through carefully curated technical content designed to reinforce long-term understanding.

Every lesson is reviewed by experienced software engineers to ensure technical accuracy, practical relevance, and alignment with modern engineering practices.

What you'll review

• Software architecture principles
• System design concepts
• Design patterns
• Distributed systems
• Databases and data modeling
• Networking fundamentals
• Concurrency and multithreading
• Performance optimization
• Backend engineering concepts
• Software engineering best practices

Built for engineers who want to

• Refresh important technical concepts
• Prepare for senior software engineering interviews
• Review architecture and system design topics
• Strengthen problem-solving skills
• Stay sharp between projects

Upstream is suitable for software engineers at different stages of their careers, especially developers preparing for technical interviews or looking to deepen their understanding of modern software engineering.

New technical content is added regularly, covering practical engineering topics used in real-world software development.

Keep your engineering skills sharp with concise, expert-reviewed technical reviews designed for modern software engineers.

What’s new

Welcome to Upstream 1.1.0!

• Initial public release.
• Structured micro-learning for experienced software engineers.
• Production-focused lessons, quick recalls, interview questions, and scenario analysis.
• Lifetime access to purchased tracks, including future content updates.

Thank you for using Upstream!