Ennyn

A local development proxy that routes requests to your services by hostname, with automatic HTTPS.

Overview

Ennyn ("Doors" in Sindarin) runs on your development machine and sits in front of your local services. Instead of juggling localhost ports, you give each service a hostname like myapp.localhost and access it over HTTPS.

All services use <name>.localhost hostnames, which resolve to 127.0.0.1 automatically on all platforms (per RFC 6761). No /etc/hosts editing required.

Features:

• Reverse proxy -- route requests to local services by hostname
• Automatic HTTPS -- local CA with a wildcard *.localhost certificate
• Process management -- starts your app and proxies to it in one command
• Instance tracking -- list running instances, stop them by name
• Cross-platform -- single binary for macOS, Linux, and Windows

Installation

Download the latest binary for your platform from Releases, or build from source (see Contributing).

Getting Started

1. Set up HTTPS (one-time)

ennyn trust

Generates a local Certificate Authority and a wildcard certificate for *.localhost, then installs the CA into your system trust store. Requires sudo/admin access.

On WSL, Ennyn detects the environment and offers to install the CA in the Windows trust store as well.

To remove the CA and all certificates:

ennyn trust --uninstall

2. Start a service

ennyn server myapp 3000 npm run dev

This starts npm run dev, then proxies myapp.localhost:7890 to 127.0.0.1:3000. Run multiple services in separate terminals:

ennyn server api 4000 go run ./cmd/api
ennyn server web 3000 npm run dev -p 3001

3. Manage running instances

ennyn list

HOST  PID    PROXY PORT  APP PORT  COMMAND  UPTIME
api   12345  7890        4000      go       2m30s
web   12346  3001        3000      npm      1m15s

Stop a specific instance:

ennyn stop api

Or press Ctrl+C in the terminal where the instance is running.

Commands

Command	Description
ennyn server [flags] <host> <app-port> <app-cmd> [args...]	Start the proxy and app
ennyn list	Show all running instances
ennyn stop <host>	Stop a running instance by hostname
ennyn trust	Generate CA and certificates, install into trust store
ennyn trust --uninstall	Remove CA from trust store and delete certificate files

Server flags

Flag	Default	Description
-p, -port	7890	Proxy port to listen on

File locations

All files stored under $XDG_CONFIG_HOME/ennyn/ (defaults to ~/.config/ennyn/):

Path	Description
ca/ca.crt	Root CA certificate
ca/ca.key	Root CA private key
ca/localhost.crt	Wildcard cert for *.localhost
ca/localhost.key	Wildcard cert private key
run/<host>.json	State file for running instance

Contributing

Prerequisites

• Go 1.25 or later

Build from source

git clone https://github.com/gmoigneu/ennyn.git
cd ennyn
go build -o ennyn .

Cross-compilation

Ennyn compiles to a single binary with no cgo dependencies:

# macOS (Apple Silicon)
GOOS=darwin GOARCH=arm64 go build -o ennyn-darwin-arm64 .

# Linux (x86_64, for WSL)
GOOS=linux GOARCH=amd64 go build -o ennyn-linux-amd64 .

# Windows
GOOS=windows GOARCH=amd64 go build -o ennyn-windows-amd64.exe .

Run tests

go test ./...
go vet ./...