# localchat: yet another local chat app POC w/GoLang + HTMX > Source: > Published: 2026-10-05 06:01:14+00:00 *This is a submission for the [Hacktoberfest Weekend Challenge: Build for a Friend](https://dev.to/challenges/hacktoberfest-weekend-2026-10-01)* localchat is a chat app for an AI model that runs on your own machine. A Go server renders the UI, and Google's **Gemma 4 E2B** writes the replies, streamed into your browser token by token. Your messages stay in memory on your laptop for as long as you run the app. I talked to a friend before about what a bare-basic and simple Go web app with AI integration would look like, without too many difficult parts. So I spent some time setting this up and kept the project small enough to read in one sitting. I picked Gemma while developing because I like running small models on my own hardware. Gemma 4 E2B fits in a few gigabytes of RAM and starts answering in about a second on my laptop. It's fast and easy to develop against while still having realistic output. My friend and I get two things: **Repo:** [git.b0b.be/bdeb/localchat](https://git.b0b.be/bdeb/localchat) ``` cmd/localchat/ entry point: serve + install/start/stop as an OS service internal/llm/ ~150-line OpenAI-compatible streaming client (stdlib only) internal/chat/ in-memory conversations, one per browser session internal/web/ routes, SSE streaming, embedded static assets internal/web/views/ Templ components scripts/e2e.py Playwright browser test against the real model compose.yaml app + llama.cpp + Gemma 4 E2B ``` On my M3 MacBook Air, Gemma 4 E2B (4-bit, through oMLX) sends its first token after about a second and finishes a short answer with a code block in 3 to 5 seconds. **Open-source AI:** Google's Gemma 4 E2B (open weights, 4-bit). I ran it with **oMLX** (Apple MLX) on my Mac while developing, and the container uses **llama.cpp** (`llama-server` with a GGUF build). **App stack:** Go 1.27, Templ, HTMX 2 with its SSE extension, goldmark and kardianos/service. ``` Browser ── HTMX + SSE extension │ POST /chat → user bubble + empty reply bubble (sse-connect) │ GET /chat/stream/{id} ← "token" events (append) … "done" (swap in Markdown) Go (net/http + Templ) │ POST /v1/chat/completions {stream: true} Local model server ── Gemma 4 E2B ``` Streaming works as plain HTML over server-sent events: `sse-connect="/chat/stream/{id}"`.`` inside a `token` event. HTMX appends each span with `hx-swap="beforeend"`, so you see the answer appear word by word. I wrote no JavaScript for the streaming.`done` event carrying the reply as server-rendered Markdown (goldmark, raw HTML stripped). HTMX swaps the whole bubble for it, and removing the `sse-connect` element closes the stream. A few more details: `bufio.Scanner` over `data:` lines, in about 150 lines of standard-library Go.`localchat install --user` registers the app as a launchd agent, a systemd unit or a Windows service, pointed at your `.env` file.