einoko / watchdog

Self-hosted website monitoring

Watchdog

Watchdog is a visual website monitoring app. It was created as a self-hosted alternative to commercial solutions such as visualping and sken.io. With Watchdog, you can monitor changes on websites. Two comparison methods are supported.

Visual comparisons

Watchdog periodically captures a screenshot of any given web page, and looks for any pixel-level changes between the current and previously captured screenshot. If a change is big enough, a notification email will be sent. You can crop the screenshot to focus only on a specific part on the page.

watchdog_demo.mp4

Sample notification

Text comparisons

Watchdog can also detect text-based changes on the page. Whenever there is a change, a notification email will be sent. You can use CSS selectors to monitor changes only in a single element. Alternatively, you can define a set of keywords, and Watchdog will notify you whenever those words are either found or not found on the page.

How to deploy

It is recommended to deploy Watchdog using Docker. However, you can also deploy it manually.

Once deployed, create a new admin account with the same username as defined in ADMIN_USERNAME. Log in, go to Settings and configure the email settings.

Docker

Backend

Provide your own values for JWT_SECRET, and APP_URL in environment in the watchdog_api container in docker-compose.yml. If needed, adjust port and network values to suit your needs.

Frontend

Add the REACT_APP_API_PATH environment variable to the watchdog_frontend container in docker-compose.yml. This should be the base URL of the API, i.e. the same value as APP_URL in watchdog_api container.

Start the containers with the following command.

docker compose up -d

The frontend should be available at port 3000.

To stop the containers, run

docker compose down

Manual deployment

Backend

In order to run the backend server, a .env file must be placed in the backend folder. Fill in the following details.

# Database settings
MONGODB_URI="mongodb://127.0.0.1:27017/watchdog"

# JWT settings
JWT_SECRET=<Some long random string>
JWT_EXPIRES_IN=<e.g. "30d">

# Port
PORT=3001

# Base URL
APP_URL=<Base URL of the api, e.g. https.//example-api.com>

# File path
FILES_PATH="./files"

# Admin username
# Account with this name will receive admin rights
ADMIN_USERNAME="admin"

After this, you can start the server. If you want to run it persistently, use forever or pm2.

Install packages needed for the server

cd backend
npm install

PM2

npm install -g pm2@latest
pm2 start index.js

Forever

npm install -g forever
forever start index.js

Frontend

Install and build.

npm install
npm run build

The built site will be in /build.