Mark Koellmann · deutschmark

deutschmark

Full-stack developer building streaming infrastructure.

I build the tools I wish existed when I started streaming. Open-source OBS overlays, chat-driven companion apps, and the back-end that keeps them honest. When something stays broken too long, I write the fix.

About

I'm a full-stack developer who streams. The thing I keep coming back to is the seam between "builds shippable software" and "runs a Twitch channel" — every overlay and companion app I make is one I'd use myself that night.

Most of my work runs on Cloudflare Workers and Next.js static export — cheap to host, fast everywhere, no server tax to keep something free. The Twitch stack is anonymous IRC for chat events and EventSub for everything Twitch removed from IRC. Spotify integration via the Web API. Configuration changes hot-swap to the live overlay over a Durable Object websocket fanout.

I like writing code that does what the box says, in fewer lines than expected, with no half-finished migrations. I don't like dashboards that won't tell you why something broke.

Selected work

Writing

More guides on the toolset docs.

Stack

TypeScriptReactNext.jsCloudflare WorkersDurable ObjectsCloudflare KVTailwind v4Three.jsWebGLRustSQLitePostgresPrismaSupabaseTwitch IRC + Helix + EventSubSpotify Web API

Contact

The fastest way to reach me is deutschmarkonline@gmail.com. I'm also on GitHub and live on Twitch a few nights a week — usually breaking the toolset on stream and fixing it before chat notices.