Havn – one command to see everything running locally

Name: Havn – one command to see everything running locally
Availability: InStock
Author: haseeb16

by haseeb16·Mar 8, 2026·2 points·1 comment

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AI Analysis

●●●BangerSolve My ProblemSlickNiche Gem

One command discovers 40+ services via HTTP fingerprinting and filesystem parsing.

Strengths

•HTTP fingerprinting (headers) + filesystem sniffing (package.json, go.mod) is clever multi-signal approach
•Zero-config single-file UI (no bundler, Express + vanilla JS) keeps barrier low
•Parallel TCP connect across 100+ ports + WebSocket push is snappy; real performance metrics (800ms→300ms cached)

Weaknesses

•Solves a very narrow pain point (local service discovery); not a platform
•Already achievable with lsof, netstat, or paid monitoring tools—convenience gain, not necessity

Post Description

I kept running lsof -i :PORT repeatedly to check what was alive locally. Eventually I wrote a small tool around it and it turned into this.

How it works: - One lsof / netstat call maps all listening processes - 100+ ports scanned in parallel via TCP connect, 150ms timeout each - HTTP fingerprinting reads response headers to identify frameworks (Spring Boot, Express, Django, etc.) - Filesystem detection reads package.json, pom.xml, go.mod, Cargo.toml from the process working directory to get the actual project name - Redis gets a PING/PONG health check, Postgres gets a connection handshake - Results pushed to the browser via WebSocket every few seconds

First scan: ~800ms. Subsequent scans: ~300-400ms. Memory: ~55MB RSS.

Detects 40+ services including databases, queues, monitoring tools, and AI runtimes (Ollama).

Single file UI, no build step, no bundler. Just HTML/CSS/JS served by Express.

npm install -g @haseeb-xd/havn && havn

GitHub: https://github.com/haseeb-xd/havn

Happy to answer questions about the detection approach or the performance tradeoffs.