Turn a Raspberry Pi Zero W into a Mini Web Server with SSH and Ngrok

Raspberry Pi (RPi) is a credit‑card‑sized Linux‑based computer popular among hobbyists; the Zero W model is a miniature version roughly one‑third the size of a Pi 3 B+ while retaining most interfaces.

Hardware specifications of the Zero W

BCM2835 1 GHz processor, 512 MB RAM

BCM43438 Wi‑Fi / Bluetooth chip

Micro‑USB power and OTG ports

Mini‑HDMI port

Composite video and reset pins

CSI camera connector

Micro‑SD slot for the OS

40‑pin GPIO header

Dimensions: 65 mm × 30 mm

The board is powerful enough to run a small website despite its modest CPU and memory.

Preparing the SD card

16 GB or 32 GB SanDisk micro‑SD card

Standard USB‑A to micro‑USB cable (not Type‑C)

SD card formatter (e.g., SDFormatter)

Win32DiskImager (or similar flashing tool)

Raspbian Stretch Lite image (official, no desktop)

Download the raspbian‑stretch‑lite.zip file (≈360 MB), unzip it, and locate the .img file (≈1.7 GB).

Flashing the image

Insert the SD card into a reader, open Win32DiskImager, select the .img file, choose the correct device, and click “Write”. After completion, safely eject the card.

Enabling head‑less SSH and Wi‑Fi

After flashing, the card will have a single boot partition (≈40 MB) visible on Windows. In this partition:

Create an empty file named ssh (no extension) to enable the SSH daemon on first boot.

Create a file named wpa_supplicant.conf with the following content, replacing YOUR_SSID and YOUR_PASSWORD with your Wi‑Fi credentials:

country=CN
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="YOUR_SSID"
    psk="YOUR_PASSWORD"
}

This makes the Zero W connect to your Wi‑Fi automatically, allowing SSH access without a monitor.

Booting and connecting

Insert the SD card into the Zero W, power it via the micro‑USB cable, and wait a few minutes. The board’s LED will flash during boot and stay solid when ready. Locate the Pi’s IP address on your router (e.g., 192.168.0.104) and connect with an SSH client (default user pi, password raspberry).

System optimisation

Because foreign apt mirrors are slow in China, replace them with a domestic mirror (e.g., USTC). Edit /etc/apt/sources.list:

sudo nano /etc/apt/sources.list
# comment existing lines and add:
deb http://mirrors.ustc.edu.cn/raspbian/raspbian/raspbian stretch main contrib non-free rpi

Also edit /etc/apt/sources.list.d/raspi.list:

sudo nano /etc/apt/sources.list.d/raspi.list
# comment existing lines and add:
deb http://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian stretch main ui

Update the package index and upgrade installed packages:

sudo apt-get update
sudo apt-get upgrade

Set the correct timezone (e.g., Asia/Shanghai):

sudo dpkg-reconfigure tzdata

Ensuring SSH starts on boot

Method 1: run sudo raspi-config, navigate to “Interfacing Options → SSH”, and enable it.

Method 2: add /etc/init.d/ssh start before the exit 0 line in /etc/rc.local so the service launches automatically after a reboot.

Installing nginx

# install nginx
sudo apt-get install nginx
# start the service
sudo /etc/init.d/nginx start
# restart if needed
sudo /etc/init.d/nginx restart
# stop the service
sudo /etc/init.d/nginx stop

Open a browser on a device in the same LAN and navigate to the Pi’s IP (e.g., http://192.168.0.104) to see the default nginx page.

Exposing the server to the internet

Use an ngrok‑compatible tunnel service. The author tested three providers (ittun, sunny, natapp) and chose the ittun arm binary because it runs on the Zero W. After registering, run the ngrok client (e.g., ngrok http 80) inside a screen session so it stays alive after logout.

When the tunnel is active, the public URL (e.g., http://zerow.ittun.com/) forwards traffic to the Pi’s nginx server, making the site reachable from anywhere.

Note: the tunnel must be restarted manually after power or network loss; automatic startup is a known limitation.

Result

After the above steps, the Zero W runs a lightweight web server, accessible locally and via an ngrok public URL, with about 250 MB free RAM and CPU temperature stable around 37‑39 °C after two days of continuous operation.

Further exploration

The Zero W can be used for many other projects; the Raspberry Pi community provides abundant tutorials and examples.