SO100 vs SO101: Which Robot Arm Should You Buy in 2026?
A detailed comparison of the SO-ARM100 and SO-ARM101 robot arms — specs, compatibility, availability, and which one is right for you.
A detailed comparison of the SO-ARM100 and SO-ARM101 robot arms — specs, compatibility, availability, and which one is right for you.
The Quick Answer
For most people in 2026, the SO100 is the better buy. It has a larger community, more tutorials, proven LeRobot compatibility, and wider availability. The SO101 offers minor mechanical improvements but isn't a generational leap. (New to the SO100? Start with our complete SO100 guide.)
Read on for the full breakdown.
Background: Where Did These Arms Come From?
Both the SO100 and SO101 were designed as part of the open-source robotics movement spearheaded by Hugging Face and The Robot Studio:
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SO100 (SO-ARM100): Released in 2024-2025. Designed by Alexander Koch at The Robot Studio. Became the reference hardware for Hugging Face's LeRobot framework. Exploded in popularity after Hugging Face's endorsement.
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SO101 (SO-ARM101): Released in late 2025. An iteration on the SO100 with mechanical refinements. Reviewed by CNX Software, 3D Printing Industry, and other tech outlets.
Specifications Comparison
| Spec | SO100 | SO101 |
|---|---|---|
| Degrees of Freedom | 6 DOF | 6 DOF |
| Servo Motors | STS3215 (30 kg·cm) | STS3215 (30 kg·cm) |
| Controller | Waveshare servo driver | Waveshare servo driver |
| Connectivity | USB-C | USB-C |
| Frame Material | 3D printed (PLA/PETG) | 3D printed (PLA/PETG) |
| Software Support | LeRobot ✅ | LeRobot ✅ |
| Joint Design | Standard | Improved bearing mounts |
| Cable Routing | External | Improved internal routing |
| Community Size | ⭐⭐⭐⭐⭐ Very Large | ⭐⭐⭐ Growing |
| Tutorials Available | Extensive | Limited |
| Availability | Widely available | Harder to find |
Key Differences Explained
1. Mechanical Improvements (SO101)
The SO101 features slightly redesigned joint housings that improve bearing alignment. This can reduce backlash (unwanted play in the joints) and improve repeatability. For most hobbyist applications, the difference is marginal. For precision research, it may matter.
2. Cable Management (SO101)
The SO101 has improved internal cable routing channels, making for a cleaner build. This is mainly a cosmetic and durability improvement — less chance of snagging cables during operation.
3. Community & Ecosystem (SO100 wins)
This is the SO100's biggest advantage:
- LeRobot was built around the SO100 — it's the primary reference hardware
- Hundreds of shared datasets on Hugging Face Hub recorded with SO100 arms
- Dozens of tutorial videos on YouTube
- Active Discord community with SO100-specific help channels
- Pre-trained models available that you can fine-tune
The SO101 is catching up, but the SO100 ecosystem is significantly more mature.
4. Availability (SO100 wins)
The SO100 is available from multiple vendors worldwide. The SO101 has limited availability and is frequently sold out.
You can buy a pre-assembled SO100 right now: so100.nanocorp.app — $299. Not sure whether to buy pre-assembled or build it yourself? Read our pre-assembled vs DIY comparison.
5. Software Compatibility (Tie)
Both arms use the same servos (STS3215) and controller (Waveshare), so LeRobot supports both equally well. Any code written for the SO100 works on the SO101 with minimal (if any) changes.
⚡ Get the SO100 Complete Kit
Pre-assembled leader + follower arms, all servos, driver boards, cables, and power supply included. Skip the build — start training AI this weekend.
Price Comparison
| Option | SO100 | SO101 |
|---|---|---|
| DIY (parts only) | $130–$200 | $130–$200 |
| Pre-assembled kit | $299 (so100.nanocorp.app) | $300–$400 (limited vendors) |
| Availability | ✅ In stock | ⚠️ Often sold out |
Which One Should You Buy?
Buy the SO100 if you:
- ✅ Want the most community support and tutorials
- ✅ Want access to hundreds of pre-recorded datasets
- ✅ Want a pre-assembled kit available NOW
- ✅ Are new to robotics or LeRobot
- ✅ Need it for a class, project, or hackathon with a deadline
- ✅ Want the proven, battle-tested choice
Buy the SO101 if you:
- You want the absolute latest mechanical design
- You plan to do precision research where backlash matters
- You're already experienced with LeRobot and want to try the newer version
- You can find one in stock
Our Recommendation
Start with the SO100. It's available now, it's proven, and the community support is unmatched. You'll get up and running faster and have more resources when you hit issues.
If you later want to add an SO101 to your collection, the skills and knowledge transfer directly. Wondering how the SO100 stacks up against other robot arms on the market? Check out our best robot arm for AI comparison.
Get the SO100 Today
SO100 Complete Kit — $299 at so100.nanocorp.app →
Pre-assembled leader + follower arms. All servos, driver boards, and cables included. LeRobot compatible out of the box. Ships from the US.
Ready to get started?
Get the SO100 Complete Kit — pre-assembled, tested, and LeRobot-ready. Ships from the US.
Get Your Kit — $299