Developer ToolingStatus: Prototype

Killit

Safety-aware cross-platform port killer for local development workflows.

GitHub

KillitDeveloper Tooling

Killit

Node.js
CLI
TUI

A look inside

4 screens from the real build. Select any to see it full size.

Terminal output of killit inspect 4120 listing port, PID, name, command, path, owner, protocol, project node and safety SAFE, followed by killit 4120 printing Killed node, and a second run printing Nothing listening on specified port(s) with exit code 0 — killit inspect shows what holds a port: the PID, command, owner, a guess at the project type, and a safety level with its reason. A SAFE process is stopped with a plain killit 4120. Running it again exits 0, because an empty port is not an error.

Terminal output of killit kill 4101 4121 4122 --dry-run listing three processes that would be killed, followed by ki 4101 4121 4122 printing Killed for two node processes and one Python process — Several ports can go in one command. --dry-run lists what would be killed without sending a signal, and the short alias ki then stops a Vite dev server, a Node server and a Python http.server.

Terminal output of killit inspect 5000 showing macOS ControlCenter with safety WARN because its binary is in a system directory, then killit 5000 refusing with a warning and exit code 2, then killit 4130 --force refusing to terminate a zsh process with exit code 2 — macOS ControlCenter holds port 5000. It is classed WARN because its binary lives under /System, so killit refuses without --force and exits 2. Shells are on a protected list, so a zsh process holding port 4130 is refused even with --force.

Terminal output: killit 4140 kills a node process, a second later killit inspect 4140 shows a new node process with a different PID on the same port, then killit 4140 --tree kills it and inspect reports Nothing listening on this port — The server on port 4140 runs under a small watcher script that restarts it, like nodemon. A plain kill frees the port only until the watcher starts a new process. --tree signals the whole process group, watcher included, so the port stays free.

Overview

Node.js CLI and programmable API that finds and safely terminates zombie processes occupying local development ports.

The problem

Developers often kill port-hogging processes manually, risking accidental termination of important system or database processes.

What I built

Built the CLI behavior, safety classification approach, cross-platform detection flow, and programmable API surface.

What it does

Port detection
Safety classification
Interactive TUI
API mode

System and architecture

A zero-dependency Node.js CLI detects listeners through native OS tools, classifies process safety, and offers an interactive TUI before termination.

A zero-dependency Node.js CLI detects listeners through native OS tools, classifies process safety with a 3-tier engine, and offers an interactive TUI before termination.

System map3 layers

Interface
API & services
Delivery

Native OS listener detection
Three-tier process safety classification
CLI and programmable API usage

Technology

Themes

Challenges and trade-offs

Supporting different OS-level process discovery tools.
Designing safe defaults for a potentially destructive command.

Outcome

At a glance

Zero dependencies · 3-tier safety engine · macOS/Linux/Windows/Docker

Built a developer tool focused on safer local process management.
Reduced risk in a common workflow by classifying processes before termination.

Learnings

Developer tools need strong guardrails around destructive actions.
Cross-platform CLIs work best with layered detection fallbacks.

See it for yourself.

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GitHub