Physical Intelligence π-0.5

Physical Intelligence
VLA / Robotics

Upgraded π-0 with open-world generalization via knowledge insulation. Weights and fine-tuning open-sourced.

Research-only model
Physical Intelligence π-0.5 runs on physical robot hardware and is not exposed via the Railwail API yet.
Not API-accessible
Read the research
TL;DR·Last updated May 16, 2026

Physical Intelligence π-0.5 is vla / robotics AI model from Physical Intelligence, priced at €0.000 per 1M input tokens with a unknown context window.

Try Physical Intelligence π-0.5

0.7

Direct API access coming soon

Pricing

Price per Generation
Per generationFree

API Integration

Use our OpenAI-compatible API to integrate Physical Intelligence π-0.5 into your application.

Install
npm install railwail
JavaScript / TypeScript
import railwail from "railwail";

const rw = railwail("YOUR_API_KEY");

// Simple — just pass a string
const reply = await rw.run("pi-0-5-pi", "Hello! What can you do?");
console.log(reply);

// With message history
const reply2 = await rw.run("pi-0-5-pi", [
  { role: "system", content: "You are a helpful assistant." },
  { role: "user", content: "Explain quantum computing simply." },
]);
console.log(reply2);

// Full response with usage info
const res = await rw.chat("pi-0-5-pi", [
  { role: "user", content: "Hello!" },
], { temperature: 0.7, max_tokens: 500 });
console.log(res.choices[0].message.content);
console.log(res.usage);
Specifications
Developer
Physical Intelligence
Category
VLA / Robotics
Supported Formats
image
text
Tags
physical-intelligence
vla
robotics
research-only
open-weights
open-world

Deep dive — Physical Intelligence (PI)'s Physical Intelligence π-0.5

About Physical Intelligence (PI)
Founded 2024 · San Francisco, California, USA

Physical Intelligence (PI) is a San Francisco robot-foundation-model startup founded in 2024 by Sergey Levine, Chelsea Finn, Karol Hausman and co-founders. π-0.5 is the upgraded successor to π-0, announced in April 2025, focused on open-world generalisation: the same robot policy is shown deploying in previously unseen real homes - making beds, cleaning kitchens, sorting laundry - without per-house fine-tuning. The π-0.5 release also expanded the openpi GitHub repository with new checkpoints, training recipes and evaluation tools. π-0.5 is positioned as the next step toward general-purpose physical intelligence and continues PI's strategy of partial open-source: research weights are public, while production-scale checkpoints and proprietary data remain internal.

Visit Physical Intelligence (PI)
Architecture
Flow-matching VLA with co-training for open-world generalisation

π-0.5 builds on the π-0 architecture (PaliGemma 3B multimodal backbone + flow-matching action expert) and introduces a co-training recipe combining heterogeneous data sources: high-quality teleoperation, web-scale image+text, multi-robot cross-embodiment data and large amounts of in-the-wild egocentric video. The training pipeline interleaves robot action prediction with auxiliary objectives (next-token prediction over instructions, captioning, scene reasoning), which significantly improves zero-shot transfer to unseen homes. Inputs remain multi-view RGB + proprioception + natural-language instruction; outputs are flow-matched continuous action chunks. The technical report shows π-0.5 generalising to homes never seen during training, performing multi-step household tasks with natural-language prompts. π-0.5 also improves on long-horizon planning by adopting a hierarchical inference strategy that issues sub-instructions through the same VLA.

Parameters
~3B (PaliGemma backbone + action expert)
Context
unknown
What it can do
  • Open-world generalisation across unseen homes
  • Long-horizon household tasks: cleaning, bed making, laundry
  • Co-training with robot data + egocentric video + web text
  • Hierarchical self-prompting for multi-step tasks
  • Flow-matching action head for smooth high-frequency control
  • Single set of weights deployed across many real homes
  • Successor to π-0 with improved language grounding
  • Partial open-source via openpi GitHub repository
  • Best for: open-world robot research, household manipulation.
Training & License

Co-trained corpus combining ~10,000+ hours of robot teleoperation, Open-X-Embodiment cross-embodiment data, large-scale egocentric / web video, and web-scale image-text pairs. Multi-stage curriculum mixing action prediction with vision-language objectives.

License: Partially open-source via the openpi GitHub repository for research use. Production deployment licensing is handled directly by Physical Intelligence.

Known limitations
  • Still confined to relatively quasi-static manipulation
  • Hardware variations cause performance regression
  • Latency and onboard compute requirements remain high
  • Generalisation to industrial / outdoor settings less proven
  • Open-source release trails internal latest checkpoint
  • Documentation primarily targets researchers, not integrators

Frequently asked questions

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