pyvgx 3.6.0

PyVGX - Vector Graph Index Python Extensions

Distributed engine for plugin-based graph and vector search

Why VGX?

VGX + 1 is WHY
+1 is you

Originally short for Vector Graph indeX, VGX is a high-performance, distributed engine for building custom search and recommendation services using Python plugins. It combines real-time graph traversal, vector similarity, and expressive filtering into a unified platform, backed by a native C-core for speed and scalability. Developers can implement service logic using the PyVGX C-extensions, expose it as HTTP endpoints, and automatically scale across a sharded, replicated back-end. With built-in support for ANN search, dynamic graphs, expression-based filtering, and pluggable infrastructure, VGX makes it easy to develop powerful, low-latency systems for semantic search, recommendation, autocomplete, and more.

About This Project

VGX was originally developed in-house at Rakuten, Inc. between 2014 and 2025 as a versatile platform for live services. Built from the ground up, it focuses on maximizing memory efficiency and hardware utilization while delivering consistent low-latency performance. In 2025, we open-sourced the platform to share its capabilities with the wider community and foster collaboration.

Getting Started

You will need Python 3.9 or higher and one of the supported operating systems:

• macOS: 14 (Sonoma) or higher
• Linux: glibc 2.34 or higher (e.g. Ubuntu 22.04+)
• Windows: 10 or higher

It is usually a good idea to use a virtual environment to keep things isolated:

MacOS / Linux venv setup

python3 -m venv vgxenv
source vgxenv/bin/activate

Windows venv setup

python -m venv vgxenv
call vgxenv\Scripts\activate.bat

Install PyVGX

pip install pyvgx

Hello VGX

Now let's define and expose a service using VGX:

Plugin Code

# hello.py
from pyvgx import *

system.Initialize("hello")

# This function will be exposed as an HTTP endpoint
def Hello(request: PluginRequest, message: str = "nothing"):
    response = PluginResponse()
    response.Append(f"Hi, you said {message}")
    return response

system.AddPlugin(Hello)

system.StartHTTP(9000) # main port=9000, admin port=9001
print("Visit 'http://127.0.0.1:9001' for admin" )

# Until SIGINT
system.RunServer()

Start Service

# Run the service
python hello.py

Send Request

# Send a request
curl http://127.0.0.1:9000/vgx/plugin/Hello?message=hello!

Simple Graph Examples

Example 1: Build relationships and ask a question

from pyvgx import *

# Make some friends
g = Graph( "friends" )
g.Connect( "Alice", "knows", "Bob" )
g.Connect( "Alice", "knows", "Charlie" )
g.Connect( "Alice", "knows", "Diane" )
g.Connect( "Charlie", "likes", "coffee" )

# Which of Alice's friends likes coffee?
g.Neighborhood(
    "Alice",
    arc      = "knows",
    neighbor = {
        'arc'      : "likes",
        'neighbor' : "coffee"
    }
) # -> ['Charlie']

Example 2: Build a vector graph and find most similar match

from pyvgx import *
import random

# Connect root to many vertices with vectors
root = g.NewVertex( "root" )
for n in range( 10000 ):
    v = g.NewVertex( f"v{n}" )
    v.SetVector( g.sim.rvec(1024) ) # assign a random vector
    r = g.Connect( root, "to", v )

# Select a target and derive a probe (add noise) from its vector
target = g["v7357"]
probe = [x + 0.5 * (random.random()-0.5) for x in target.GetVector().external]

# Run a query around root and sort by similarity to probe vector
g.Neighborhood(
    id="root",
    hits=3,
    fields=F_ID|F_RANK,
    vector=probe,
    sortby=S_RANK,
    rank="cosine(vector, next.vector)"
) # -> ['{"id": "v7357", "rankscore": 0.97...}', ...]

VGX Demo System

If you want to see a larger demo system in action, type the following in a terminal:

# Start a multi-node VGX system
vgxdemosystem multi

This will start many server instances (using ~16GB RAM) and open a system dashboard in your web browser:

Allow startup to finish and then try to send a query to the dispatcher running on port 9990:

# Run test queries, return JSON search result
curl -s http://127.0.0.1:9990/vgx/plugin/search?name=7357 | jq
curl -s http://127.0.0.1:9990/vgx/plugin/search?name=index | jq

You can see how the demo is implemented here: vgxdemoservice.py and vgxdemoplugin.py

To stop the system type this in a terminal:

vgxdemoservice stop

Documentation

Comprehensive API documentation is available.

• VGX Documentation Home

A few quick links:

• PyVGX Tutorial
• PyVGX Reference
• PyVGX Compact Reference
• VGX Expression Language
• VGX Server

Recommendation: Read the Tutorial first. It covers some of the graph basics without going too deep.

Maintainers

This project was open-sourced by Rakuten, Inc. and is currently maintained by:

• Stian Lysne – @slysne
• Contact: slysne.dev [at] gmail [dot] com

For questions, issues, or contributions, feel free to open an issue or pull request.

License

This project is licensed under the Apache License Version 2.0. See LICENSE for details.