-- Sharding in permissionless systems in presence of an adaptive adversary. -- Concurrent Wait-Free Graph Snapshots using Multi-Versioning. -- Blockchain based Massively Multiplayer Online Game Architecture. -- Agent-Driven BFS Tree in Anonymous Graphs with Applications. -- Some new results with k-set agreement. -- A Domain Specific Language for Testing Distributed Protocol Implementations. -- Tool Augmented LLMs for Big Data Analysis. -- Static Data Race Detection via Lazy Sequentialization. -- Algebraic Computations in Anonymous VANET. -- Federated Learning for Enhanced Medical Image Analysis. -- Towards Stronger Blockchains: Security Against Front-Running Attacks. -- Distributed Station Assignment through Learning. -- An Efficient Framework for supporting Nested Transaction in STMs. -- Enhancing Cost and Latency Efficiency through Service Placement in Containerized Fog-Cloud Computing Environments. -- Towards Generating a Dataset for Failure Prediction in Microservices Applications. -- Dynamic Resource Allocation for 5G Device-to-Device Communication Based on Expected SARSA. -- BeRGeR: Byzantine-Robust Geometric Routing.

This book constitutes the refereed proceedings of the 12th International Conference on Networked Systems, NETYS 2024, held in Rabat, Morocco, during May 29-31, 2024. The 14 full papers and 3 short papers presented were carefully reviewed and selected from 42 submissions. NETYS aims to bring together researchers and engineers from the theory and practice of distributed and networked systems. The scope of the conference covers all aspects related to the design and the development of networked systems, e.g., cloud systems, formal verification, concurrent and distributed algorithms, data management, data science and parallel/concurrent/distributed programming. Additionally, this year NETYS also featured works on the emerging topic of distributed machine learning, also commonly referred to as federated learning.