# Free-Threading

URL: /docs/concepts/free-threading/
Section: concepts

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What is free-threading? Python 3.13+ introduced an experimental free-threaded build (python3.14t) that disables the Global Interpreter Lock (GIL). Multiple threads can execute Python bytecode simultaneously. Why Zoomies is free-threading native Zoomies was built from scratch for 3.14t: No C extensions with limited API — Only depends on cryptography, which is 3.14t-compatible Frozen dataclasses — All events are immutable. No shared mutable state between threads No global state — Each QuicConnection is independent Sans-I/O — No internal threads, locks, or async. The caller controls concurrency Running with free-threading # Install Python 3.14t uv python install 3.14t # Disable GIL PYTHON_GIL=0 python3.14t your_server.py Thread-safe patterns Each QuicConnection instance should be owned by one thread. Multiple connections can run in parallel across threads without synchronization. import threading from zoomies.core import QuicConnection, QuicConfiguration def handle_connection(config, datagram, addr): conn = QuicConnection(config) events = conn.datagram_received(datagram, addr) # ... handle events ... # Each thread gets its own connection — no locks needed for datagram, addr in incoming: t = threading.Thread(target=handle_connection, args=(config, datagram, addr)) t.start() Verifying free-threading import sys print(sys._is_gil_enabled()) # False on 3.14t with PYTHON_GIL=0

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- Author: lbliii
- Word Count: 179
- Reading Time: 1 minutes