Open source · Featured · 2023
P2P Chat Application.
Sockets, from scratch.
presentsAdmit one
Act I
The challenge
Most chat apps quietly route everything through a server. For a networks course, the whole point was to not do that: real peer-to-peer messaging on raw sockets, with a registry only for discovery and a heartbeat tracking who’s actually online.
Act II
What I built
A Python CLI chat built on raw sockets. A threaded central registry handles auth and discovery, but every peer also runs its own TCP server for direct one-to-one chat, presence rides a UDP heartbeat, and MongoDB-backed rooms fan messages out over UDP.
Intermission, the demo
The product, playing itself
a packet and its ack, no server in between, the whole point, in one hop
The cast
What actually makes it work
Read the card, then flip it to watch the mechanism run.
0x01
Presence protocol
A self-rescheduling one-second UDP heartbeat plus a per-user timeout reaper on the registry keeps an accurate online list without polling.
how it works
Presence protocol
0x02
Hybrid topology
The registry stays centralized for auth and discovery while messaging is decentralized, so each client is at once a TCP client and its own threaded TCP server.
how it works
Hybrid topology
0x03
UDP room fan-out
Member IP and port lists come from the registry, and room messages go out as direct datagrams to each member under registry-side locks.
how it works