The technology behind Colada
Colada is two halves: a local-first desktop app that runs entirely on your machine, and an optional hosted platform for accounts, sync, sharing, a live realtime layer and anonymous analytics. Here's what powers each, and why.
How it fits together
The desktop app works with none of this — the platform is entirely optional. When you do sign in, the browser only ever talks to the gateway, never directly to identity or the data stores.
Desktop app Local, private, offline-first
A tiny local web server that runs the entire app on your machine — no cloud round-trips.
No SPA framework: fast, dependency-light, server-rendered pages that install as an app (PWA).
Gapless playback, smart queues and session resume, all client-side.
20+ GPU-smooth styles drawn frame-by-frame from the live audio signal.
Local models (Ollama) or a cloud provider, driven through an MCP server so any assistant can DJ.
Genres, synced lyrics and a semantic read on every track’s mood & energy.
State lives in your OS app-data folder — there is no database server to run.
Hosted platform Optional accounts & sync
This marketing site and the account portal, server-rendered for speed and SEO.
A separate internal tool for the catalogue, users and analytics — on its own deploy, gated to admin accounts at the app and the API.
The single edge: routing, JWT auth, per-origin rate-limiting and CORS.
Profiles, avatars and consent — brokered server-side via a BFF so tokens never touch the browser.
Standards-based auth (incl. Google sign-in); the browser never sees admin credentials.
A fast columnar store for anonymous, pseudonymous usage events.
A 1:1 live socket per active listener — signed-in or anonymous — for now-playing presence, live “here now” counts and instant notifications.
A durable, replayable event log: one service emits, many react independently — analytics, notifications and the realtime fan-out.
Every event on the bus uses the CNCF standard envelope rather than a house format, so other systems can read it without learning ours.
Transactional email over HTTPS — verification and native password resets.
Infrastructure Simple on purpose
The whole platform as containers, defined in one file.
One right-sized Droplet — deliberately simple and cheap to run.
Automatic HTTPS and reverse proxy in front of everything.
DNS for colada.fm.
Tests, container image builds and the private registry.
Curious how it all came together?
Read the behind-the-scenes →