Merlion is a mature Python library for time series intelligence, specializing in anomaly detection and forecasting. It provides a comprehensive, modular ecosystem including model zoo (classical, tree-based, deep learning, ensemble, AutoML), composable transforms, post-processing chains, evaluation frameworks, and a Dash-based interactive dashboard. The architecture follows a clean layered design: data loading via `ts_datasets`, core `TimeSeries` abstraction, `ModelBase` hierarchy with config-driven instantiation, invertible transforms, and pluggable post-rules. It integrates with Spark for distributed inference and provides benchmarks against standard datasets (NAB, M4, UCR). Though primarily a library (application), it includes research-oriented components such as state-of-the-art transformer architectures (Autoformer, Informer) and Bayesian change point detection, making it a hybrid tool suitable for both production and research.