[Feature Request] Add async support to Python SDK for production use with FastAPI/async frameworks

[minhluan1590]

Summary

The current Python SDK only provides synchronous methods, which creates significant challenges when integrating PageIndex into production async web frameworks like FastAPI, Starlette, or any asyncio-based application.

Problem

When using the sync SDK in an async context, we're forced to use asyncio.to_thread():

from pageindex import PageIndexClient

@app.post("/chat")
async def chat(query: str):
    client = PageIndexClient(api_key=API_KEY)
    response = await asyncio.to_thread(
        client.chat_completions,
        messages=[{"role": "user", "content": query}],
        doc_id=["doc-1"]
    )
    return response

This approach has several issues:

• Thread pool exhaustion - Python's default thread pool is limited (~40 threads)
• Increased latency - Thread context switching adds overhead
• Resource inefficiency - Threads blocked waiting for I/O
• Scalability limits - Cannot handle high concurrent request volumes

Use Case

We're building a Vietnamese administrative procedures (TTHC) chatbot using FastAPI and LangGraph (async-first). PageIndex's reasoning-based retrieval is excellent for our complex legal documents, but the sync-only SDK is a blocker for production deployment.

Proposed Solution

Add an async client alongside the existing sync client:

from pageindex import AsyncPageIndexClient

async def main():
    client = AsyncPageIndexClient(api_key=API_KEY)

    response = await client.chat_completions(
        messages=[{"role": "user", "content": query}],
        doc_id=["doc-1"]
    )

    tree = await client.get_tree(doc_id)
    status = await client.get_document_status(doc_id)

Implementation suggestion: Use httpx.AsyncClient instead of requests for HTTP calls.

Alternatives Considered

1. Thread pool approach - Works but doesn't scale
2. Build custom async wrapper - Maintenance burden
3. Use different RAG solution - Would lose PageIndex's reasoning capabilities

Environment

• Python SDK version: 0.2.4
• Python version: 3.12
• Framework: FastAPI + LangGraph

Additional Context

Many modern Python API SDKs provide both sync and async clients (OpenAI, Anthropic, Stripe). This pattern is well-established and would make PageIndex more accessible to the async Python ecosystem.

Happy to contribute a PR if the team provides guidance on the preferred approach.