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Physical Intelligenceπ (pi) familyLegacyRobotics modelReleased 16 Jan 2025

π0-FAST

Autoregressive sibling of π0 built on the FAST tokenizer.

Model idgs://openpi-assets/checkpoints/pi0_fast_base

PricePrice not published

Checked29 September 2026

Where it stands

30newer robotics models since its release

The 5 newest are listed. All robotics models

Before it from Physical Intelligence
π0 (pi-zero)31 Oct 2024
After it from Physical Intelligence
π0.522 Apr 2025
Weights
Weights are public. Licence: apache-2.0; weights built on PaliGemma, Gemma terms apply. See the licence for commercial terms.

How to call it

2 ways to use π0-FAST, with the model id each provider expects.

Providers, model ids, endpoints and docs for π0-FAST
ProviderModel idEndpointDocs
GitHub (openpi) gs://openpi-assets/checkpoints/pi0_fast_base github.com
Hugging Face (LeRobot port) lerobot/pi0fast-base Docs
Model page

Pricing

Price not published.

No price source linked. Checked 29 September 2026.

Specs

Input
Text and images
Output
Robot actions
Context window
Not published
Max output
Not published
Open weights
Yes
Licence
apache-2.0 (openpi code); weights built on PaliGemma, Gemma terms apply
Released
16 January 2025
Status
Legacy
Type
Robotics model

What stands out

What its maker marketed at launch, and what people found later, each with its source.

  • 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: huggingface.co

  • DROID generalist checkpoint

    Found after launch

    pi0_fast_droid runs zero-shot on Franka DROID setups for many table-top instructions (openpi).

    Source: github.com

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.

Sources: HF blog: π0 and π0-FAST, PI on X, openpi.