Veltix

The high-level TCP library Python never had.

Sync, thread-friendly, zero dependencies : TCP done right.
Veltix handles framing, threading, handshake, routing, and reconnection
so you can focus on your application logic.

77k msg/s • 0.035ms latency • 4KB idle • 2x throughput vs threading

Mature & tested - 261+ tests · CI on Python 3.8-3.14 · 10+ releases

Raw Socket vs Veltix

Echo server with raw sockets (41 lines):

import socket
import threading


def handle_client(conn, addr):
    while True:
        data = conn.recv(1024)
        if not data:
            break
        conn.sendall(data)
    conn.close()


server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("0.0.0.0", 8080))
server.listen(5)

while True:
    conn, addr = server.accept()
    threading.Thread(target=handle_client, args=(conn, addr)).start()

Same thing with Veltix (11 lines):

from veltix import Server, ServerConfig, ClientInfo, Response, MessageType, Request

ECHO = MessageType(code=200, name="echo")
server = Server(ServerConfig(host="0.0.0.0", port=8080))
sender = server.get_sender()


@server.route(ECHO)
def on_echo(client: ClientInfo, response: Response):
    sender.send(Request(ECHO, response.content), client=client.conn)


server.start()

No manual framing. No thread management. No boilerplate.

What you get out of the box:

• Message framing: no more recv() loops and buffer handling
• Protocol routing: @server.route(MY_TYPE) instead of if/elif chains
• Automatic handshake: HELLO/HELLO_ACK with version compatibility
• Built-in ping/pong: bidirectional latency measurement, zero config
• Auto-reconnect: configurable retry with disconnect state callbacks
• Message integrity: CRC32 verification on every message
• Request/Response: send_and_wait() with timeout and correlation
• Thread-safe callbacks: slow handlers never block reception
• Client tagging: attach metadata, broadcast to groups
• Integrated logger: colorized, rotating, thread-safe

Designed for: LAN tools, multiplayer games, real-time dashboards, custom protocols, IPC, remote tooling, file transfer.

Table of Contents

• Raw Socket vs Veltix
• Installation
• Quick Start
• Backend Comparison: Threading vs Async
• Performance
• When NOT to use Veltix
• Comparison
• Built with Veltix
• Documentation
• Contributing
• License

Installation

pip install veltix

Requirements: Python 3.8+, no additional dependencies.

Quick Start

Server:

from veltix import Server, ServerConfig, ClientInfo, Response, MessageType, Request

CHAT = MessageType(code=200, name="chat")

server = Server(ServerConfig(host="0.0.0.0", port=8080))
sender = server.get_sender()


@server.route(CHAT)
def on_message(client: ClientInfo, response: Response):
    print(f"[{client.addr[0]}] {response.content.decode()}")
    sender.broadcast(Request(CHAT, response.content), server.get_all_clients_sockets())


server.start()

input("Press Enter to stop...")
server.close_all()

Client:

from veltix import Client, ClientConfig, Response, MessageType, Request

CHAT = MessageType(code=200, name="chat")

client = Client(ClientConfig(server_addr="127.0.0.1", port=8080))


@client.route(CHAT)
def on_message(response: Response):
    print(f"Server: {response.content.decode()}")


client.connect()

client.get_sender().send(Request(CHAT, b"Hello Server!"))
input("Press Enter to disconnect...")
client.disconnect()

python server.py
python client.py  # In a separate terminal

Backend Comparison: Threading vs Async

Veltix lets you switch between two socket backends via SocketCore. Pick the one that fits your use case.

Quick rule of thumb:

• Few clients, simple logic, want easy debugging? Use THREADING.
• Many clients, high throughput, memory-conscious? Use ASYNC.

from veltix import SocketCore

server = Server(ServerConfig(socket_core=SocketCore.THREADING))  # or .ASYNC

Performance

Benchmarked on Python 3.14.5 : 12-core CPU, 30.5 GB RAM, Linux (loopback).

Full benchmark details, methodology, and how to run them yourself : PERFORMANCE.md

When NOT to use Veltix

Veltix is great for TCP, but not every problem is a TCP problem.

• HTTP/REST APIs: use Flask, FastAPI, or Django REST Framework
• Browser clients: Veltix speaks raw TCP, not WebSocket; use websockets or Socket.IO
• Async-first codebases: Veltix is sync by design; use asyncio directly if your whole project is async
• Ultra high throughput (>100k msg/s per connection): consider a compiled language for the hot path
• Single request-response: if you just need to fetch something once, requests or urllib is simpler

Everything else? Veltix has you covered.

Comparison

Built with Veltix

Projects using Veltix in production:

• Nexo : Fast LAN file transfer tool CLI + GUI. Uses Veltix's TCP server, client tags, route decorators, and send_and_wait() for reliable chunked file transfers with concurrent connection handling.

Built something with Veltix ? Open a PR or start a discussion to add your project.

Documentation

• Full documentation
• Advanced features
• Migration guide
• Changelog
• Examples

Contributing

Contributions are welcome. Please read CONTRIBUTING.md before submitting a pull request.

• Bug reports : Open an issue
• Discussions : Join the Discord
• Pull requests : Follow the contribution guide

License

MIT License : see LICENSE for details.

Links

• GitHub : NytroxDev/Veltix
• PyPI : pypi.org/project/veltix
• Documentation : https://nytroxdev.github.io/Veltix/
• Discord : discord.gg/76AeXdST9m