Qwen/WebWorld-8B
WebWorld 🌐
         
📚 Introduction
WebWorld is a large-scale open-web world model series for training and evaluating web agents. It is trained on 1M+ real-world web interaction trajectories via a scalable hierarchical data pipeline, supporting:
- Long-horizon simulation (30+ steps)
- Multi-format state representations: A11y Tree, HTML, XML, Markdown, and natural language
- CoT-activated reasoning for transition prediction
- Cross-domain generalization to code, GUI, and game environments
Agents trained on WebWorld-synthesized trajectories achieve +9.9% on MiniWob++ and +10.9% on WebArena. When used for inference-time lookahead search, WebWorld outperforms GPT-5 as a world model.
🎯 Model Series
WebWorldData: Huggingface: Qwen/WebWorldData, ModelScope: Qwen/WebWorldData
💡 Recommendation: Use 8B for fast simulation and data synthesis; use 14B/32B for higher-fidelity simulation and better long-horizon robustness. For best results in a specific environment, we recommend task-specific fine-tuning on in-domain trajectories.
🛠️ Requirements
transformers(recommended: latest version)torch- Optional:
accelerate,vllmfor efficient serving
🚀 Quick Start
Key Notes:
- WebWorld predicts the next page state given the current state and an action.
- It strictly preserves the input/output format (A11y / HTML / XML / Markdown / NL).
- Supports multi-turn trajectory simulation up to 30+ steps.
Single-Step Prediction
<details> <summary>💻 Click to expand code</summary>
import torch
from transformers import AutoTokenizer, AutoModelForCausalLM
model_name = "Qwen/WebWorld-8B" # or WebWorld-14B, WebWorld-32B
tokenizer = AutoTokenizer.from_pretrained(model_name, trust_remote_code=True)
model = AutoModelForCausalLM.from_pretrained(
model_name,
device_map="auto",
torch_dtype=torch.bfloat16,
trust_remote_code=True,
).eval()
system_prompt = (
"You are a web world model. I will provide you with an initial page state "
"and a sequence of actions. For each action, predict the resulting page state.\n"
"Strictly maintain the original format. Output only the full page state "
"without explanations, code, or truncation."
)
current_state = """RootWebArea 'Global Start - Your Daily Portal', focused
\t[1] banner 'Top Header', visible
\t\t[2] link 'Set as Homepage', clickable, visible
\t\t[3] link 'Feedback', clickable, visible
\t\t[5] region 'Weather Widget', visible
\t\t\tStaticText 'New York, USA'
\t\t\t[6] image 'Sunny', visible
\t\t\tStaticText '24°C'
\t\t[8] link 'Sign In', clickable, visible
\t[10] region 'Search Area', visible
\t\t[11] image 'Global Start Logo', visible
\t\tStaticText 'Search the entire web'
\t\t[12] tablist 'Search Engine Selector', orientation='horizontal'
\t\t\t[13] tab 'Google', selected=True, clickable
\t\t\t[14] tab 'Bing', selected=False, clickable
\t\t\t[15] tab 'DuckDuckGo', selected=False, clickable
\t\t[18] combobox 'Web Search', clickable, visible, autocomplete='both', expanded=False
\t\t\t[19] textbox 'Type keywords or URL...', clickable, visible, editable, value=''
\t\t[20] button 'Search', clickable, visible
\t[30] navigation 'Category Bar', visible
\t\t[31] link 'Home', clickable, selected=True
\t\t[32] link 'News', clickable
\t\t[33] link 'Video', clickable
\t\t[34] link 'Shopping', clickable
\t\t[35] link 'Social', clickable
\t[50] main 'Site Directory', visible
\t\t[51] region 'Top Recommended', visible
\t\t\t[52] heading 'Most Popular', visible
\t\t\t[53] list 'Top Sites Grid', visible
\t\t\t\t[54] link 'Facebook', clickable
\t\t\t\t[56] link 'YouTube', clickable
\t\t\t\t[58] link 'Amazon', clickable
\t\t\t\t[60] link 'Twitter / X', clickable
\t\t\t\t[62] link 'Instagram', clickable
\t\t\t\t[64] link 'Wikipedia', clickable
\t\t\t\t[66] link 'Netflix', clickable
\t\t\t\t[68] link 'LinkedIn', clickable
\t\t[80] region 'News & Media', visible
\t\t\t[81] heading 'Latest News', visible
\t\t\t[82] link 'CNN', clickable
\t\t\t[83] link 'BBC', clickable
\t\t\t[84] link 'The Verge', clickable
\t\t[90] region 'Shopping', visible
\t\t\t[91] heading 'E-Commerce', visible
\t\t\t[92] link 'eBay', clickable
\t\t\t[93] link 'Walmart', clickable
\t\t\t[94] link 'Best Buy', clickable
\t[200] complementary 'Ads', visible
\t\t[201] image 'Ad: Travel to Japan'
\t\t[202] link 'Book Now', clickable
\t[300] contentinfo 'Footer', visible
\t\tStaticText '© 2026 Global Start Inc.'"""
user_message = (
f"Initial Page State:\n{current_state}\n\n"
f"First Action: 'click([32])'\n\n"
f"Next Page State:"
)
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": user_message},
]
text = tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
inputs = tokenizer(text, return_tensors="pt").to(model.device)
with torch.no_grad():
outputs = model.generate(
**inputs,
max_new_tokens=4096,
do_sample=False,
)
response = tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:], skip_special_tokens=True)
print(response)</details>
Multi-Turn Simulation
The first turn provides the initial state and first action. Each subsequent turn uses a fixed continuation prompt:
<details> <summary>💻 Click to expand code</summary>
CONTINUE_PROMPT = (
"Continue the trajectory. Given the previous state, "
"predict the next page state after this action.\n\n"
"Action: '{action}'\n\nNext Page State:"
)
# Turn 1
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": f"Initial Page State:\n{state_0}\n\nFirst Action: '{action_0}'\n\nNext Page State:"},
]
state_1 = generate(messages) # your generate function
# Turn 2
messages.append({"role": "assistant", "content": state_1})
messages.append({"role": "user", "content": CONTINUE_PROMPT.format(action=action_1)})
state_2 = generate(messages)
# Turn 3, 4, ... up to 30+ turns: repeat the same pattern
messages.append({"role": "assistant", "content": state_2})
messages.append({"role": "user", "content": CONTINUE_PROMPT.format(action=action_2)})
state_3 = generate(messages)</details>
🎮 Action Space
WebWorld supports a unified action space as Python-style function calls:
📊 Performance
Intrinsic Evaluation (WebWorld-Bench)
WebWorld-Bench evaluates models using Factuality Score (functional correctness) and Web Turing Score (perceptual realism) across nine dimensions:
Extrinsic Evaluation (Agent Training)
Cross-Domain Generalization
⚠️ Limitations
- Sycophancy / optimism bias: the model may generate outcomes that are overly favorable to the agent's intended action.
- Content generation fidelity: long-form, high-precision content (e.g., scientific articles) is not the primary target.
- Text-only: WebWorld does not simulate visual / pixel-level rendering.
📝 Citation
@misc{xiao2026webworldlargescaleworldmodel,
title={WebWorld: A Large-Scale World Model for Web Agent Training},
author={Zikai Xiao and Jianhong Tu and Chuhang Zou and Yuxin Zuo and Zhi Li and Peng Wang and Bowen Yu and Fei Huang and Junyang Lin and Zuozhu Liu},
year={2026},
eprint={2602.14721},
archivePrefix={arXiv},
primaryClass={cs.AI},
url={https://arxiv.org/abs/2602.14721},
}