Transform your understanding of promises, async/await, and the event loop with our comprehensive course. From beginner confusion to expert confidence in one structured learning journey.
Everything you need to master JavaScript async programming
Progressive learning from basics to advanced patterns
Each challenge builds upon the previous one, ensuring you develop a solid foundation before moving to complex concepts.
One payment, forever access
Learn at your own pace, revisit concepts anytime, and get all future updates included.
Hints, explanations & real-world context
Every challenge includes detailed explanations and industry insights from years of professional development experience.
10 days, no questions asked
Not satisfied with the course? Get a full refund within 10 days of purchase.
Free 1-on-1 call if you don't get it
If you still don't understand promises and async/await after completing the course, I'll personally tutor you in a free online session.
Connect with fellow learners
Join our exclusive community for additional support, networking, and sharing insights with other developers.
Join hundreds of developers who've transformed their understanding of promises, async/await, and the event loop.
Try out JS Brain Teasers with this course, free of charge. Get a feel for the platform and see if you can complete this very basic challenge.
Maybe you just learned how to code in javascript, but you are struggling to understand how promises work, why to use async/await or what microtasks and macrotasks are? This course is for you!
Learn about my teaching approach and course philosophy
You get access to 30+ carefully structured challenges that build your knowledge progressively, complete with hints, detailed explanations, and real-world context. Plus lifetime access to the platform, entry to our exclusive Slack community, a 10-day money-back guarantee, and my personal promise: if you don't understand async concepts after completion, I'll tutor you myself in a free online call.
Having led teams at companies like My Neighbor Alice and mentored developers throughout my career, I bring real-world scenarios into every lesson. You'll learn not just how to write code, but how to think about scalability, maintainability, and team collaboration - skills I've honed while building systems for fintech, IoT, and ed-tech companies.
As a technical team lead and advisor who's passionate about coaching, I understand the importance of proper guidance. Each challenge comes with detailed explanations and context from my industry experience. Plus, I've structured the courses to build your problem-solving skills gradually, just like I've done while mentoring junior developers in my teams.
Absolutely! These courses are designed to strengthen your understanding of JavaScript fundamentals and advanced concepts that frequently come up in technical interviews. You'll practice solving algorithmic challenges, learn to explain your thought process clearly, and master key concepts like async programming, closures, and event loops that interviewers love to test. The hands-on exercises will build your confidence in tackling whiteboard problems and technical discussions.
Learn from real industry experience
Hi, I'm Jesper Loso, a senior full-stack developer with over a decade of experience building complex systems for fintech, edtech, and IoT companies. I've led teams at My Neighbor Alice, helped scale Aira's IoT platform, and built trading systems at Handelsbanken Capital Markets.
Throughout my career, I've mentored dozens of developers and seen the same async programming challenges come up again and again. That's why I created these courses - to give you the structured, practical understanding that usually takes years to develop through trial and error.