Jack Chan started programming at the age of 10. He was an active participant in worldwide programming contests at university. Since graduation, he has been working in the finance and IT industries for more than 10 years, building systems that analyze millions of transactions and positions to spot suspicious activity. He has leveraged the powerful analytical Python libraries to perform data analysis and performance optimization for a trading system that works at a microsecond level. He has an in-depth knowledge of the modern software development life cycle, which uses automated testing, continuous integration, and agile methodologies. Among all programming languages, he found Python to be the most expressive and powerful. He has created courses and taught students all over the world, using Python as the teaching language. Inspiring aspiring developers to take on the software engineering career path has always been Jack's goal. Ray Chung is a developer and an instructor. He loves helping students learn to code and master software development. He is now self-employed and develops web applications, network applications, and chatbots using Python. The first program he sold was a network application that helps clients configuring, maintaining, and testing thousands of multi-vendor network devices. He's experienced with big projects like a marathon's online registration system, rental car management system, and so on. He has worked extensively with Google App Engine, PostgreSQL, and advanced system architecture design. He has been a self-taught developer for many years and knows what is the most efficient way to learn a new skill. Jack Huang is a programmer with an experience of more than 7 years in developing web applications in Python, JavaScript, and .NET. He is skilled in web frameworks such as Flask, Django, and Vue. He is also skilled in PostgreSQL, DynamoDB, MongoDB, RabbitMQ, Redis, Elasticsearch, RESTful APIs design, payment processing, system architecture design, database design, and UNIX systems. He has written applications for an accessories shop platform, the ERP system, divination web application, podcast platform, Job search service, blog system, salon reserving system, e-commerce service, and so on. He also has experience in handling large data and improving its performance and optimizing payment processing. He is an expert of web application developers who love coding and constantly following the newest technology.