Feeling lost in the world of software architecture? This software architecture book is for you! Years ago, I felt lost when I started in software architecture. There were so many topics and issues, and I was a novice architect in the middle. I didn't know where to start building applications, what key areas to pay attention to, or how to build systems that would be able to evolve over many years. I have spent countless hours and days learning to recognize this area, and it has not been easy—knowledge was scattered throughout the Internet, books, and tutorials. Finally, mentors helped me get on the right track. That's why I decided to write this software architecture book. I want to help you navigate this complex world of hard decisions, trade-offs, and techniques that will support you in this fantastic journey. I wish you didn't have to make the same mistakes as me and give up your private life by spending many hours looking for the right information. Each step describes practically the most important aspects of software architecture: STEP 1: Understand Software Architecture. In this step, you will learn the basics of software architecture, covering key areas like business analysis, solution architecture, and infrastructure. You'll understand the role of software architects, their influence on architectural decisions, and the impact of drivers like functional requirements, technical constraints, and quality attributes while exploring how pragmatism and holism shape these decisions. STEP 2: Discover Your Business Domain. Through workshops on Event Storming and Domain Storytelling, you will learn to analyze processes, discover subdomains, define bounded contexts, and create a context map (strategic DDD). STEP 3: Recognize the Environment Around You. Understanding your work environment, including decision-making processes, project goals, budget limitations, and differing expectations of stakeholders and development teams. You will assess team skills with a competency matrix, plan infrastructure for various team setups, and learn to calculate crucial metrics like active users, request numbers, and SLA-defined availability. STEP 4: Choose Deployment Strategy. Focusing on single and multiple deployment unit strategies and their most popular representatives: modular monoliths and microservices. You will learn about communication methods, database design, deploying changes, scaling applications, and key patterns like outbox, inbox, and dead letter queue. STEP 5: Define Release Strategy. Usingbasic, blue-green, canary, and rolling deployments and leveraging continuous delivery and deployment. You will adopt engineering practices such as swarming, pair and mob programming, feature flags, trunk-based development, and short-living branches. STEP 6: Focus On Testing. You will learn about the pyramid of tests, the inverted pyramid, the diamond, when to use each, penetration, performance, and load testing to ensure software reliability. STEP 7: Evolve Your Architecture. This step highlights that architecture evolves over time, focusing on four key steps: simplicity, maintainability, growth, and complexity. You'll learn helpful concepts like CQRS, database replicas and sharding, and tactical DDD. STEP 8: Don't Forget About Security. You will learn about common security vulnerabilities in greenfield and legacy applications, such as IDOR, supply chain attacks, SQL injection, XSS, and DDoS. You'll also explore defense strategies, misconceptions leading to vulnerabilities, and the differences between encoding, encryption, and hashing to select the appropriate mechanism for your needs. Additionally, in this book, you will find practical architecture exercises.