Industry Track -- Serving Hybrid-Cloud Interactive SQL Queries at Twitter -- Blended Graphical and Textual Modelling of UML-RT state-machines: an industrial experience -- Diversity, Equity and Inclusion Track (DE&I) -- Toward Awareness Creation of Common Challenges Women are Facing in Academia: A Case Study from a German Perspective -- 8th Workshop on Software Architecture Erosion and Architectural Consistency (SAEroCon) -- Mapping Source Code to Modular Architectures using Keywords -- Hierarchical Code-to-Architecture Mapping -- 1st International Workshop on Mining Software Repositories for Software Architecture (MSR4SA) -- Building the MSR Tool Kaiaulu: Design Principles and Experiences -- 1st International Workshop on Software Architecture and Machine Learning (SAML) -- Self-adaptive Machine Learning Systems: Research Challenges and Opportunities -- 4th Context-aware, Autonomous and Smart Architectures International Workshop (CASA) -- Behavioral Maps:Identifying Architectural Smells in Self-Adaptive Systems at Runtime -- An Architectural Approach for Enabling and Developing Cooperative Behaviour in Diverse Autonomous Robots -- A Probabilistic Model for Effective Explainability Based on Personality Traits -- 5th International Workshop on Formal Approaches for Advanced Computing Systems (FAACS) -- Interactive Elicitation of Resilience Scenarios based on Hazard Analysis Techniques -- 2nd International Workshop on Model-Driven Engineering for Software Architecture (MDE4SA) -- Towards an Extensible Approach for Generative Microservice Development and Deployment Using LEMMA -- Tools and Demonstrations Track -- Applying Knowledge-driven Architecture Composition with Gabble -- Tutorial Track -- Architectural Optimization for Confidentiality under Structural Uncertainty -- Foundations and Research Agenda for Simulation of Smart Ecosystems Architectures.

This book constitutes the refereed proceedings of the tracks and workshops which complemented the 15th European Conference on Software Architecture, ECSA 2021, held in Växjö, Sweden*, in September 2021. The 15 full papers presented in this volume were carefully reviewed and selected from 17 submissions. Papers presented were accepted into the following tracks and workshops: Industry Track; DE&I - Diversity, Equity and Inclusion Track; SAEroCon - 8th Workshop on Software Architecture Erosion and Architectural Consistency; MSR4SA - 1st International Workshop on Mining Software Repositories for Software Architecture; SAML - 1st International Workshop on Software Architecture and Machine Learning; CASA - 4th Context-aware, Autonomous and Smart Architectures International Workshop; FAACS - 5th International Workshop on Formal Approaches for Advanced Computing Systems; MDE4SA - 2nd International Workshop on Model-Driven Engineering for Software Architecture; Tools and Demonstrations Track; Tutorial Track. *The conference was held virtually due to the COVID-19 pandemic.