As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/pi-0-fast/

# π0-FAST

Physical Intelligence, π (pi) family. Status: legacy. Type: robotics model. Released: 2025-01-16.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| GitHub (openpi) | `gs://openpi-assets/checkpoints/pi0_fast_base` |  | https://github.com/Physical-Intelligence/openpi |
| Hugging Face (LeRobot port) | `lerobot/pi0fast-base` |  | https://huggingface.co/docs/lerobot/pi0fast https://huggingface.co/lerobot/pi0fast-base |

## Pricing

- Price not published.
- Last checked: 2026-09-29

## Specs

- Input: text, image
- Output: action
- Context window: not published
- Max output: not published
- Open weights: yes
- Licence: apache-2.0 (openpi code); weights built on PaliGemma, Gemma terms apply

## Where it stands

- Newer robotics models in the registry since its release: 30. The 5 newest:
  - Praxis-1 (2026-09-30) https://postcutoff.com/m/praxis-1/
  - Helix 2.5 (2026-09-17) https://postcutoff.com/m/figure-helix-2-5/
  - UnifoLM-WLA-1.0 (2026-09-10) https://postcutoff.com/m/unifolm-wla-1-0/
  - Skild S1 (Skild Brain) (2026-08-25) https://postcutoff.com/m/skild-s1/
  - Generalist GEN-1.5 (2026-08-19) https://postcutoff.com/m/generalist-gen-1-5/
- Before it from Physical Intelligence: π0 (pi-zero) (2024-10-31) https://postcutoff.com/m/pi-0/
- After it from Physical Intelligence: π0.5 (2025-04-22) https://postcutoff.com/m/pi-0-5/
- Weights are public. Licence: apache-2.0; weights built on PaliGemma, Gemma terms apply. See the licence for commercial terms.

## What stands out

- FAST action tokenizer (autoregressive VLA): Frequency-space Action Sequence Tokenization (DCT + BPE) compresses action chunks ~10x, letting an autoregressive VLA learn dexterous high-frequency tasks and train up to 5x faster than diffusion/flow π0. Source: https://huggingface.co/blog/pi0
- DROID generalist checkpoint (found after launch): pi0_fast_droid runs zero-shot on Franka DROID setups for many table-top instructions (openpi). Source: https://github.com/Physical-Intelligence/openpi

## Notes

FAST tokenizer released and open-sourced mid-January 2025 (X post by @physical_int, 2025-01-16 approx.); π0-FAST weights open-sourced in openpi on 2025-02-04. Not marked first: no explicit 'first' claim verified.

Autoregressive sibling of π0 built on the FAST tokenizer.

Sources: [HF blog: π0 and π0-FAST](https://huggingface.co/blog/pi0), [PI on X](https://x.com/physical_int/status/1879963467836453067), [openpi](https://github.com/Physical-Intelligence/openpi).

Model page: https://postcutoff.com/m/pi-0-fast/