Apache Airflow has become the de facto standard for workflow orchestration. At its heart lies a simple but powerful mechanism for task-to-task communication: XCom (short for "Cross-Communication"). By default, Airflow allows any task to push any piece of data—whether it’s a filename, a model accuracy score, or a JSON blob—to be pulled by any downstream task.
multiple_outputs=False (default)When a task returns a dict, Airflow pushes each key independently. This can cause fragmentation. Use single return values or multiple_outputs=True carefully. airflow xcom exclusive
Value: Any serializable object, typically strings, numbers, or small JSON-compatible dictionaries. Mastering Apache Airflow: The Ultimate Guide to XCom
: By default, these messages are stored in Airflow's metadata database. The "Exclusive" Twist: Custom Backends Use BRPOPLPUSH to move to "processing" list, process,