head to head · open source
dagster vs Arize Phoenix
dagster has 16,183 GitHub stars, 2,296 forks, 2,589 open issues and last shipped 2 days ago. Arize Phoenix has 11,544 stars, 1,140 forks, 970 open issues and last shipped yesterday. dagster leads on adoption by 40% (16,183 vs 11,544 stars). dagster is written in Python under Apache-2.0; Arize Phoenix is written in Python under a custom or non-standard licence. dagster has attracted 14% as many forks as stars, Arize Phoenix 10%. Arize Phoenix was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| dagster | Arize Phoenix | |
|---|---|---|
| GitHub stars | ★ 16K | ★ 12K |
| License | Apache-2.0 | Custom / other |
| Written in | Python | Python |
| Last push | 2026-09-18 | 2026-09-19 |
| Forks | ⑂ 2.3K | ⑂ 1.1K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick dagster if
- You weight community size — 16K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick Arize Phoenix if
- You want the Arize Phoenix feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Python
- You evaluated both and Arize Phoenix fits your workflow better
About dagster
Dagster is a cloud native data pipeline orchestrator written in Python and released under the Apache 2.0 licence, built for data engineers, data scientists, and machine learning teams who declare the tables, data sets, models, and reports their pipelines should produce and need those assets tested, observable, and kept up to date from local development through production.
read the full dagster overview →
About Arize Phoenix
Arize Phoenix is an open source AI observability platform for experimentation, evaluation, and troubleshooting. It lives in the machine learning infrastructure ecosystem and is written in Python. The project provides tracing, evaluation, datasets, experiments, prompt management, and a playground for LLM applications.
read the full Arize Phoenix overview →
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Frequently asked questions
Is dagster or Arize Phoenix more popular?
dagster has 16,183 GitHub stars and Arize Phoenix has 11,544. dagster has the larger community by that measure.
Are dagster and Arize Phoenix free?
Both are open source. dagster is licensed under Apache-2.0, and Arize Phoenix has no licence declared in this registry. Both are free to self-host.
What is the difference between dagster and Arize Phoenix?
dagster is written in Python and Arize Phoenix in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, dagster or Arize Phoenix?
Choose dagster if you want the larger community (16,183 stars) or its Apache-2.0 licence terms. Choose Arize Phoenix if its feature set, stack or Custom / other licence fits better. Both are self-hostable.