Identity
- Status
- active
- Developer ID
allenai/MolmoAct2- Released
- May 5, 2026
- Version
- 2
- License
- apache-2.0
Ai2MolmoAct 2
Ai2's open action reasoning model for real-world robot control and post-training across single-arm and bimanual tasks.
- Model type
- Action reasoning model
- Inputs
- Text, Image, Robot state
- Inference
- Flexible
- Released
- May 5, 2026
Providers & Pricing
0 current hosted offerings
No Hosted API Available
This record is downloadable or self-hosted. Its cost depends on the infrastructure and serving configuration, not a universal model price.
At a Glance
Model Facts
Model Design
- Model type
- Action reasoning model
- Inputs
- Text, Image, Robot state
- Outputs
- Robot action
- Total parameters
- 5B
- Architecture
- Molmo 2-ER backbone with KV-cache bridge and action expert
Deployment
- Inference
- Flexible
- Control rate
- Unknown
- API available
- No
- Open weights
- Yes
- Self-hostable
- Yes
Publisher Media
MolmoAct 2 Demonstrations
Embodied Intelligence
Robotics Control Profile
Control Contract
Model typeAction reasoning model
Action representationFlow-matching continuous action expert
Control architectureMolmo 2-ER backbone with KV-cache bridge and action expert
InferenceFlexible
Native control rateUnknown
Training Data and Embodiments
Open bimanual YAM, SO-100/SO-101, DROID, BC-Z, Fractal, Bridge, and prior MolmoAct data described by Ai2.
Verified Platform Links
Compatible Robots
| Robot | Relationship | Form | Availability | Evidence note | Source |
|---|---|---|---|---|---|
 SO-101Hugging Face LeRobot | Training embodiment | Fixed manipulator | Open build | Ai2 lists SO-100/SO-101 datasets in the MolmoAct 2 training mixture and publishes an SO-100/SO-101 checkpoint. | Official fact |
This page represents one developer model product. Dated API snapshots, serving endpoints, pricing, regions, quantizations, and service tiers attach as versioned aliases or provider details and never create duplicate public model records.
Version Lineage
PredecessorUnknown
SuccessorsUnknown
Aliasesallenai/MolmoAct2
Explicit Unknowns
- Native control rate
Primary Evidence
Sources and Observation Date
Comparable Peers
Related Model Comparisons
| A | Pair | B | Context |
|---|---|---|---|
MolmoAct 2Ai2 | vs |  Helix 02Figure | cross-developer peersrobotics |
MolmoAct 2Ai2 | vs |  Gemini Robotics 2Google DeepMind | cross-developer peersrobotics |
MolmoAct 2Ai2 | vs | SmolVLA 450MHugging Face LeRobot | cross-developer peersrobotics |
MolmoAct 2Ai2 | vs |  GR00T N1.7 3BNVIDIA | cross-developer peersrobotics |
MolmoAct 2Ai2 | vs |  OpenVLA 7BOpenVLA Research Team | cross-developer peersrobotics |
MolmoAct 2Ai2 | vs |  pi 0.7Physical Intelligence | cross-developer peersrobotics |
Questions
MolmoAct 2 FAQs
What is MolmoAct 2?+
Ai2's open action reasoning model for real-world robot control and post-training across single-arm and bimanual tasks. It is developed by Ai2 and its current sourced lifecycle status is active.
What inputs and outputs does MolmoAct 2 support?+
MolmoAct 2's current record lists Text, Image, and Robot state as input and Robot action as output.
What kind of robotics model is MolmoAct 2?+
MolmoAct 2 is classified as a action reasoning model. Its action representation is Flow-matching continuous action expert, its control architecture is Molmo 2-ER backbone with KV-cache bridge and action expert, and inference is recorded as flexible.
Which robots and embodiments work with MolmoAct 2?+
The developer reports SO-100, SO-101, Franka, WidowX, and bimanual YAM as supported or represented embodiments. Model Markets also has sourced model-to-platform links for SO-101; each link states whether it is native, demonstrated, used for training, or used for evaluation.
How large is MolmoAct 2?+
The current record lists 5B total parameters and an unknown active parameter count. Its architecture is Molmo 2-ER backbone with KV-cache bridge and action expert.
What capabilities and tasks does MolmoAct 2 support?+
MolmoAct 2's recorded capabilities are action-reasoning, bimanual-manipulation, depth-reasoning, and fine-tuning. Its supported tasks are robot-control, dexterous-manipulation, and bimanual-manipulation.
What training data is reported for MolmoAct 2?+
Open bimanual YAM, SO-100/SO-101, DROID, BC-Z, Fractal, Bridge, and prior MolmoAct data described by Ai2.
Is MolmoAct 2 available through an API?+
MolmoAct 2 is explicitly marked as not API-available in the current record.
How much does MolmoAct 2 cost through an API?+
MolmoAct 2 has no verified hosted API offering, so no provider token price applies. It is a downloadable or self-hosted artifact whose cost depends on the serving infrastructure and workload.
Can MolmoAct 2 be self-hosted?+
MolmoAct 2 is an open-weight model. Self-hosting is supported, and the recorded license is apache-2.0.