[Docs] Add portable API (#87)

Add Portable API to How-To

docs/how_to/engine_integration.rst

@@ -97,8 +97,8 @@ as we will see in :ref:`how-to-engine-integration-batched`.
   # Instantiate grammar matcher with the compiled grammar
   matcher = xgr.GrammarMatcher(compiled_grammar)
 
-Auto-regressive Generation with xgr.GrammarMatcher
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Bitmasking Logits in Auto-regressive Generation
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Now we simulate a single-request auto-regressive generation. See later section for
 :ref:`how-to-engine-integration-batched`.

docs/how_to/portable_api.rst

@@ -0,0 +1,25 @@
+.. _how-to-portable-api:
+
+Portable API
+============
+
+XGrammar is implemented with a lightweight C++ core that can be integrated into many platforms.
+Besides the C++ backend, we also provide ready-to-use Python and JavaScript/TypeScript libraries.
+
+For the Python library, simply check out the :ref:`Python API Reference <apixgrammar>`. Below
+we take a high-level view of the Javascript library.
+
+.. _how-to-portable-js:
+
+Javascript SDK for Web-based LLMs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The JS SDK is designed to be used for LLMs that run in the browser, including
+`WebLLM <https://github.com/mlc-ai/web-llm>`__. WebLLM integrated with XGrammar's 
+JS SDK, ``web-xgrammar``. It uses `emscripten <https://emscripten.org/>`__ to compile
+the C++ code into WebAssembly.
+
+To use this SDK, simply run ``npm install @mlc-ai/web-xgrammar``. For more, see
+`here <https://github.com/mlc-ai/xgrammar/tree/main/web>`__.
+
+

docs/index.rst

@@ -30,6 +30,7 @@ Check out :ref:`quick-start` for quick start examples of using XGrammar.
    how_to/json_generation.rst
    how_to/ebnf_guided_generation.rst
    how_to/engine_integration.rst
+   how_to/portable_api.rst
    .. tutorials/web_sdk.rst              .. TODO