Pretty domains for
local development
Map localhost:3000 to https://myapp.local with path routing,
HTTPS, WebSocket passthrough, and zero config.
$ slim start web --port 3000
✓ https://web.local → localhost:3000
$ slim start myapp --port 3000 --route /api=8080
✓ https://myapp.local
→
localhost:3000
https://myapp.local/api
→
localhost:8080
$ slim up # .slim.yaml
✓ https://myapp.local
→
localhost:3000
https://myapp.local/api
→
localhost:8080
✓ https://dashboard.local
→
localhost:5173
MIT Licensed · macOS & Linux · Single Binary
$ curl -sL https://slim.sh/install.sh | sh Install using script above or build from source.
Automatic HTTPS Trusted certificates, green lock, no warnings.
WebSocket & HMR Next.js, Vite, and others work out of the box.
Multiple Domains Each gets its own certificate and proxy.
Access Logging Full, minimal, or off. Tail and filter by domain.
Health Monitoring See which upstreams are reachable at a glance.
Path Routing Route different URL paths to different upstream ports.
Project Config Share your dev setup with teammates via .slim.yaml.
Zero Config First run handles CA, trust, and port forwarding.
Commands
Everything is one slim command away.
slim start <name> Map a domain to a port
slim start <name> Map a domain to a port # Map your Next.js app
$ slim start myapp --port 3000
# Add your API server
$ slim start api -p 8080
# Route /api requests to a different port
$ slim start myapp -p 3000 --route /api=8080
# Enable access logging
$ slim start dashboard -p 5173 --log-mode full
# Wait for upstream to be ready
$ slim start myapp -p 3000 --wait --timeout 30s slim list See what's running
slim list See what's running # Show all domains with health status
$ slim list
# Output as JSON
$ slim list --json slim logs View access logs
slim logs View access logs # Tail all access logs
$ slim logs
# Follow logs for a specific domain
$ slim logs -f myapp
# Clear all logs
$ slim logs --flush slim up Start all services from .slim.yaml
slim up Start all services from .slim.yaml # Start all services from .slim.yaml
$ slim up
# Or specify a config path
$ slim up --config /path/to/.slim.yaml slim down Stop project services
slim down Stop project services # Stop all project services
$ slim down
# Or specify a config path
$ slim down --config /path/to/.slim.yaml slim stop Stop proxying
slim stop Stop proxying # Stop a specific domain
$ slim stop myapp
# Stop all domains and shutdown daemon
$ slim stop slim doctor Diagnose setup issues
slim doctor Diagnose setup issues # Check your local setup
$ slim doctor slim uninstall Remove everything
slim uninstall Remove everything # Removes everything: CA, certs, hosts entries,
# port-forward rules, and config
$ slim uninstallProject Config
Share your local dev setup with teammates using a .slim.yaml file.
services:
- domain: myapp
port: 3000
routes:
- path: /api
port: 8080
- domain: dashboard
port: 5173
log_mode: minimal
Run slim up to start every service in one shot, and slim down to tear them all down.
# Start all services defined in .slim.yaml
$ slim up
# Or specify a config path
$ slim up --config /path/to/.slim.yaml
# Stop all project services
$ slim downPath Routing
Route different URL paths to different upstream ports on the same domain.
# Route /api and /ws to different ports
$ slim start myapp --port 3000 --route /api=8080 --route /ws=9000
Requests to https://myapp.local/api/* go to port 8080, while everything else hits 3000. Routes also work in your project config:
services:
- domain: myapp
port: 3000
routes:
- path: /api
port: 8080
- path: /ws
port: 9000Diagnostics
Run slim doctor to check your local setup at a glance.
$ slim doctor
✓ CA certificate valid, expires 2035-02-28
✓ CA trust trusted by OS
✓ Port forwarding active (80→10080, 443→10443)
✓ Hosts: myapp.local present in /etc/hosts
! Daemon not running
✓ Cert: myapp.local valid, expires 2027-06-03
Checks your CA certificate, OS trust, port forwarding rules, hosts file entries, daemon status, and per-domain certificates.
How it works
A single Go binary that handles everything under the hood.
1
Generates a root CA and trusts it in macOS Keychain or Linux CA store.
2
Creates per-domain certificates on demand, served via SNI for each
.local domain. 3
Manages
/etc/hosts entries automatically, pointing domains to 127.0.0.1. 4
Forwards ports 80/443 via
pfctl or iptables so the proxy runs unprivileged. 5
Reverse proxies requests with HTTP/2, WebSocket upgrades, and CORS headers.