Apache Airflow is the widely adopted open-source orchestrator where pipelines are Python-defined DAGs, with a large provider ecosystem and multiple managed offerings.

Dagster is an open-source orchestrator organized around software-defined assets — declaring the tables and models pipelines produce — with strong local development and testing.

Prefect is an open-source orchestration framework where plain Python functions become flows and tasks, aimed at dynamic, failure-tolerant pipelines with minimal boilerplate.