kitio.aiMetaflow vs Union.ai
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Metaflow is completely free, while Union.ai is free trial.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Workflows in plain Python
- Automatic versioning
- One-command production deploy
- Cloud compute and GPUs
- Event-based triggers
- Durable, resumable workflows
- Runs in your own cloud
- Distributed training
- Inference gateway
- Multi-cluster scheduling
- Lineage and artifacts
| Feature | Metaflow | Union.ai |
|---|---|---|
| Best for | Open-source Python framework for ML and AI workflows | Durable AI workflow runtime that runs inside your own cloud |
| Category | Models & APIs | Models & APIs |
| Pricing model | Free | Free trial |
| Starting price | Free | $950/mo |
| Free plan | Yes, fully free | No, trial available |
| Made by | Outerbounds | Union.ai |
| Based in | – | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Metaflow is completely free, while Union.ai is free trial.
Free plan
Cheapest paid plan
Top plan
Free trial
2 plans
Team
$950/mo
- Minimum, credited back as usage
- 2 active clusters
- 30-day data retention
- Standard 12x5 support
Enterprise
Custom
- Annual commit credited to usage
- Volume discounts on every meter
- Multi-region and multi-cloud
Prices in USD, checked Oct 29, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Metaflow
- Free and open source
- Same code runs locally and in production
- Tracks every step automatically
- Requires Python skills
- Cloud setup takes effort
Union.ai
- Data never leaves your infrastructure
- Failed steps resume where they stopped
- Plain Python on top of open-source Flyte
- $950 monthly minimum after the first month
- Meant for platform teams, not beginners
- Usage pricing takes effort to estimate
Which one should you choose?
Choose Metaflow if you want:
- Free and open source
- Same code runs locally and in production
- Tracks every step automatically
Watch out: requires python skills.
Choose Union.ai if you want:
- Data never leaves your infrastructure
- Failed steps resume where they stopped
- Plain Python on top of open-source Flyte
Watch out: $950 monthly minimum after the first month.
Metaflow vs Union.ai FAQ
What is the difference between Metaflow and Union.ai?
Metaflow: Open-source Python framework for ML and AI workflows. Union.ai: Durable AI workflow runtime that runs inside your own cloud. Both are models & apis tools.
Is Metaflow or Union.ai cheaper?
Metaflow is completely free, while Union.ai is free trial.
Do Metaflow and Union.ai have free plans?
Metaflow: Yes, fully free. Union.ai: No, trial available.
Who makes Metaflow?
Metaflow is made by Outerbounds.
Who makes Union.ai?
Union.ai is made by Union.ai, based in United States.
Which should I choose, Metaflow or Union.ai?
Choose Metaflow if you value free and open source and same code runs locally and in production. Choose Union.ai if you value data never leaves your infrastructure and failed steps resume where they stopped.