APIMonitor

A Windows system tray application that monitors an API endpoint and displays its status as a tray icon. The icon changes color based on the API response, giving an at-a-glance view of service health.

Features

• System tray icon that reflects API status (success, fail, error)
• Configurable API URL with live validation, check interval, logging toggle, and history limit
• Modern WebView2-based configuration and history dialogs (React + Tailwind CSS)
• Status change history with timestamps, copy-to-clipboard, and clear
• Configuration stored in the Windows registry (HKCU\SOFTWARE\JPIT\APIMonitor)
• First-launch configuration dialog
• Automatic retry on network errors (3 attempts, 2s delay)
• Accelerated polling (every 10s) when the API is in a non-success state
• Log file at ProgramData\APIMonitor\APIMonitor.log (auto-truncated at 10MB)
• Single-instance enforcement
• Display/DPI change detection for RDP reconnects

Requirements

• Windows 7+
• Microsoft Edge WebView2 Runtime — required for the configuration and history dialogs. Usually pre-installed on Windows 10/11; can be downloaded from Microsoft.

API Response Format

The monitored endpoint must return XML containing a <result> (or short <r>) tag with a value of success or fail. An optional <message> tag provides detail shown in the tooltip.

Success Response

<result>success</result>
<message>All systems operational</message>

Or using the short tag:

<r>success</r>
<message>All systems operational</message>

Fail Response

<result>fail</result>
<message>Database connection timeout</message>

Tray Icon States

State	Icon	Refresh Interval
Success	Green	Configured interval (default 60s)
Fail	Red	10 seconds
Error (network/HTTP)	Empty	10 seconds
Invalid (bad XML)	Empty	10 seconds

Building

Requires MinGW-w64 cross-compiler and Node.js (for the frontend build).

make

This builds the React frontend (assets/dist/index.html), compiles resources, and outputs release/APIMonitor.exe.

To regenerate .ico files from .svg sources (requires ImageMagick):

make icons

To clean all build artifacts (including assets/dist and assets/node_modules):

make clean

Configuration

On first launch a configuration dialog is shown. It can also be opened from the tray icon right-click menu under Configure.

Setting	Registry Value	Type	Default
API URL	ApiUrl	REG_SZ	http://example.com/api/status
Check Interval	RefreshInterval	REG_DWORD	60 (seconds)
Enable Logging	LoggingEnabled	REG_DWORD	1
History Limit	HistoryLimit	REG_DWORD	100 (10–10,000)

Settings are stored under HKEY_CURRENT_USER\SOFTWARE\JPIT\APIMonitor.

If a config.ini file exists from a previous version, settings are migrated to the registry on first launch.

Project Structure

├── main.c              # Application source (tray icon, API polling, WebView2 integration)
├── resource.h          # Resource IDs
├── resources.rc        # Resource definitions (icons, HTML, DLL)
├── Makefile            # Cross-compilation build system
├── assets/
│   ├── src/
│   │   ├── App.tsx           # Root component (view router, resize reporting)
│   │   ├── ConfigView.tsx    # Configuration form with URL validation
│   │   ├── HistoryView.tsx   # Status change history table
│   │   ├── lib/
│   │   │   ├── bridge.ts     # C <-> JS communication bridge
│   │   │   └── utils.ts      # Tailwind merge utility
│   │   └── components/ui/    # Reusable UI components (button, input, switch, etc.)
│   ├── *.ico, *.svg          # Tray icons and source SVGs
│   ├── WebView2Loader.dll    # Embedded WebView2 loader
│   ├── package.json          # Frontend dependencies
│   ├── vite.config.ts        # Vite + single-file plugin config
│   └── tailwind.config.ts    # Tailwind CSS config
└── release/
    └── APIMonitor.exe        # Built executable

License

MIT