diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
new file mode 100644
index 0000000..8b01fae
--- /dev/null
+++ b/.github/workflows/docs.yml
@@ -0,0 +1,52 @@
+name: Deploy docs to GitHub Pages
+
+on:
+  push:
+    branches:
+      - "main"
+    paths:
+      - "docs/**"
+      - "mkdocs.yml"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install MkDocs
+        run: pip install -r docs/requirements.txt
+
+      - name: Build docs
+        run: mkdocs build --strict
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: site/
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4
diff --git a/docs/api.md b/docs/api.md
new file mode 100644
index 0000000..3e27eb2
--- /dev/null
+++ b/docs/api.md
@@ -0,0 +1,84 @@
+# API Reference
+
+## `guide` — Tag Builder
+
+A singleton instance of `Guide` for creating masked tags. Import it as `g` by convention:
+
+```python
+from gimkit import guide as g
+```
+
+### Methods
+
+| Method | Description |
+|---|---|
+| `g(name, desc, regex, content)` | Create a generic masked tag with optional attributes. |
+| `g.single_word(name)` | A single word without spaces (`\S+`). |
+| `g.select(name, choices)` | Choose one value from the given list of options. |
+| `g.datetime(name, require_date, require_time)` | A date and/or time string, e.g. `2023-10-05 14:30:00`. |
+| `g.person_name(name)` | A person's name, e.g. *John Doe*, *张三*. |
+| `g.phone_number(name)` | A phone number, e.g. *+1-123-456-7890*. |
+| `g.e_mail(name)` | An email address, e.g. *alice@example.com*. |
+
+### `MaskedTag` attributes
+
+| Attribute | Type | Description |
+|---|---|---|
+| `name` | `str | None` | Tag name for named access in results. |
+| `desc` | `str | None` | Natural-language description sent to the model. |
+| `regex` | `str | None` | Regex pattern constraining model output. |
+| `content` | `str | None` | Filled content (set after model inference). |
+
+---
+
+## `from_openai` — OpenAI Backend
+
+```python
+from gimkit import from_openai
+from openai import OpenAI
+
+model = from_openai(client: OpenAI, model_name: str)
+result = model(query, use_gim_prompt=True)
+```
+
+Returns a callable model. Supports both synchronous and asynchronous calls.
+
+---
+
+## `from_vllm` — vLLM Server Backend
+
+```python
+from gimkit import from_vllm
+
+model = from_vllm(base_url: str, model_name: str)
+result = model(query)
+```
+
+Requires `pip install gimkit[vllm]` on Linux.
+
+---
+
+## `from_vllm_offline` — vLLM Offline Backend
+
+```python
+from gimkit import from_vllm_offline
+
+model = from_vllm_offline(model_name: str)
+result = model(query)
+```
+
+Requires `pip install gimkit[vllm]` on Linux.
+
+---
+
+## `Query` and `Response`
+
+Low-level classes for working with GIM-formatted strings directly:
+
+```python
+from gimkit.contexts import Query, Response, infill
+
+query = Query(f"Hello, {g(name='word', desc='a single word')}!")
+response = Response(f"<|GIM_RESPONSE|>...<|/GIM_RESPONSE|>")
+result = infill(query, response)
+```
diff --git a/docs/index.md b/docs/index.md
new file mode 100644
index 0000000..7894160
--- /dev/null
+++ b/docs/index.md
@@ -0,0 +1,24 @@
+# GIMKit
+
+**Guided Infilling Modeling Toolkit** — precise structured text generation using language models.
+
+GIMKit lets you define placeholders (masked tags) in text and have a language model fill them in. It gives you fine-grained control over model outputs through a typed tag system with optional regex constraints.
+
+[![PyPI Version](https://img.shields.io/pypi/v/gimkit?label=pypi%20package)](https://pypi.org/project/gimkit)
+[![Python Versions](https://img.shields.io/pypi/pyversions/gimkit.svg)](https://pypi.org/project/gimkit)
+[![Platform](https://img.shields.io/badge/Platform-Linux%20%7C%20macOS%20%7C%20Windows-lightgrey)](https://pypi.org/project/gimkit)
+
+---
+
+## Features
+
+- **Masked tag system** — embed typed placeholders directly in f-strings.
+- **Regex constraints** — restrict model output to specific patterns.
+- **Named access** — retrieve results by tag name or index.
+- **Multiple backends** — OpenAI, vLLM (server and offline).
+- **Small-model friendly** — designed to work well with compact open-source models.
+
+## Design Philosophy
+
+- **Stable over feature** — reliability and correctness are prioritized above new features.
+- **Small open-source model first** — designed to work well with small, freely available language models.
diff --git a/docs/installation.md b/docs/installation.md
new file mode 100644
index 0000000..837874a
--- /dev/null
+++ b/docs/installation.md
@@ -0,0 +1,25 @@
+# Installation
+
+## Standard
+
+Install GIMKit using pip:
+
+```bash
+pip install gimkit
+```
+
+## With vLLM support
+
+Install with the optional `vllm` extra to enable the vLLM backends:
+
+```bash
+pip install gimkit[vllm]
+```
+
+!!! note
+    vLLM is only supported on Linux. On Windows and macOS, omit the `[vllm]` extra.
+
+## Requirements
+
+- Python 3.10 or later
+- Linux, macOS, or Windows
diff --git a/docs/quickstart.md b/docs/quickstart.md
new file mode 100644
index 0000000..e0a2a64
--- /dev/null
+++ b/docs/quickstart.md
@@ -0,0 +1,35 @@
+# Quick Start
+
+Here is a minimal example using the OpenAI backend.
+
+## 1. Set up the client
+
+```python
+from openai import OpenAI
+from gimkit import from_openai, guide as g
+
+client = OpenAI()  # reads OPENAI_API_KEY from environment
+model = from_openai(client, model_name="gpt-4")
+```
+
+## 2. Create a query with masked tags
+
+```python
+result = model(f"Hello, {g(desc='a single word')}!", use_gim_prompt=True)
+print(result)  # Hello, world!
+```
+
+## 3. Run a structured form
+
+```python
+query = f"""
+Name: {g.person_name(name="name")}
+Email: {g.e_mail(name="email")}
+Favorite color: {g.select(name="color", choices=["red", "green", "blue"])}
+"""
+
+result = model(query, use_gim_prompt=True)
+print(result.tags["name"].content)   # e.g. Alice
+print(result.tags["email"].content)  # e.g. alice@example.com
+print(result.tags["color"].content)  # red | green | blue
+```
diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 0000000..2d9b3cf
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1,2 @@
+mkdocs>=1.6.1
+mkdocs-material>=9.6.23
diff --git a/docs/usage.md b/docs/usage.md
new file mode 100644
index 0000000..256dbc1
--- /dev/null
+++ b/docs/usage.md
@@ -0,0 +1,87 @@
+# Usage Guide
+
+## Creating Masked Tags
+
+Use the `guide` helper (conventionally imported as `g`) to create masked tags:
+
+```python
+from gimkit import guide as g
+
+# Basic tag with description
+tag = g(name="greeting", desc="A friendly greeting")
+
+# Specialized tags
+name_tag  = g.person_name(name="user_name")
+email_tag = g.e_mail(name="email")
+phone_tag = g.phone_number(name="phone")
+word_tag  = g.single_word(name="word")
+
+# Selection from choices
+choice_tag = g.select(name="color", choices=["red", "green", "blue"])
+
+# Tag with regex constraint
+code_tag = g(name="code", desc="A 4-digit PIN", regex=r"\d{4}")
+```
+
+## Building Queries
+
+Masked tags can be embedded directly in Python f-strings:
+
+```python
+from gimkit import from_openai, guide as g
+from openai import OpenAI
+
+client = OpenAI()
+model = from_openai(client, model_name="gpt-4")
+
+query = f"""
+Name: {g.person_name(name="name")}
+Email: {g.e_mail(name="email")}
+Favorite color: {g.select(name="color", choices=["red", "green", "blue"])}
+"""
+
+result = model(query, use_gim_prompt=True)
+print(result)
+```
+
+## Accessing Results
+
+Tags in the result can be accessed by index or by name:
+
+```python
+result = model(query, use_gim_prompt=True)
+
+# Iterate over all tags
+for tag in result.tags:
+    print(f"{tag.name}: {tag.content}")
+
+# Access a specific tag by name
+print(result.tags["name"].content)
+
+# Access by index
+print(result.tags[0].content)
+
+# Modify tag content
+result.tags["email"].content = "REDACTED"
+```
+
+## Using vLLM
+
+```python
+from gimkit import from_vllm
+
+model = from_vllm(base_url="http://localhost:8000", model_name="your-model")
+result = model(query)
+```
+
+For offline inference without a running server:
+
+```python
+from gimkit import from_vllm_offline
+
+model = from_vllm_offline(model_name="your-model")
+result = model(query)
+```
+
+!!! note
+    `from_vllm` and `from_vllm_offline` require `pip install gimkit[vllm]` on Linux.
diff --git a/mkdocs.yml b/mkdocs.yml
new file mode 100644
index 0000000..2f297c7
--- /dev/null
+++ b/mkdocs.yml
@@ -0,0 +1,44 @@
+site_name: GIMKit
+site_url: https://sculptai.github.io/GIMKit
+site_description: Guided Infilling Modeling Toolkit — precise structured text generation with language models.
+site_author: Shichao Song
+repo_name: SculptAI/GIMKit
+repo_url: https://github.com/SculptAI/GIMKit
+
+theme:
+  name: material
+  palette:
+    - scheme: default
+      primary: indigo
+      accent: indigo
+      toggle:
+        icon: material/brightness-7
+        name: Switch to dark mode
+    - scheme: slate
+      primary: indigo
+      accent: indigo
+      toggle:
+        icon: material/brightness-4
+        name: Switch to light mode
+  features:
+    - navigation.top
+    - content.code.copy
+
+nav:
+  - Home: index.md
+  - Installation: installation.md
+  - Quick Start: quickstart.md
+  - Usage Guide: usage.md
+  - API Reference: api.md
+
+markdown_extensions:
+  - pymdownx.highlight:
+      anchor_linenums: true
+  - pymdownx.superfences
+  - pymdownx.inlinehilite
+  - admonition
+  - attr_list
+  - tables
+
+exclude_docs: |
+  requirements.txt
diff --git a/pyproject.toml b/pyproject.toml
index f32cb17..94e8119 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,7 +41,7 @@ vllm = [
 
 [project.urls]
 Homepage = "https://github.com/SculptAI/GIMKit"
-Documentation = "https://github.com/SculptAI/GIMKit"
+Documentation = "https://sculptai.github.io/GIMKit"
 Repository = "https://github.com/SculptAI/GIMKit"
 Issues = "https://github.com/SculptAI/GIM/issues"