Real-time · Self-hosted · Open source

Monitor APIs
without vendor
lock-in.

Lightweight, self-hosted endpoint monitoring. Real-time status updates, live latency line charts, and smart email alerts — running entirely on your infrastructure.

Designed for VPS, homelabs, and production monitoring.

Test in Playground Self-Host with Docker
~60MB
Docker image
0 calls
External services
100%
Data ownership
— Features

Everything you need.
Nothing you don't.

From endpoint checks to live latency line charts — full visibility, zero overhead.

Real-Time Monitoring

Live status via Server-Sent Events — no polling, no delays. HTTP, HTTPS, WS, and WSS all supported.

Latency Line Charts

30-check rolling line charts per endpoint. Spot degradation before your users notice.

Smart Email Alerts

Threshold-based alerts with cooldown. Up to 5 recipients. Signal only, no noise.

Privacy-First

Everything stays on your server. Zero vendor lock-in, zero telemetry, zero third-party calls.

Custom Requests

Choose method, set custom headers and body, define expected status codes, configure check intervals.

SQLite Storage

Zero-setup persistence. A single file, automatic cleanup. No separate database container.

— Quick Deploy

Up and running in four steps.

Single container, no orchestration needed. Email alerts are configured via environment variables. Pass your SMTP credentials and they work immediately.

01
Clone the repository
git clone https://github.com/your-username/koala.git
cd koala
02
Review the Docker Compose file
cp docker-compose.example.yml docker-compose.yml
# (optional) edit ports, volumes, and env vars
The compose file includes the API, dashboard, and SQLite volume.
03
Add SMTP config for email alerts
SMTP_HOST=smtp.gmail.com
SMTP_PORT=587
SMTP_EMAIL=your-email@gmail.com
SMTP_PASSWORD=your-app-password
Use a Gmail App Password — not your real password.
04
Run on your VM
docker compose up --build -d
Recommended: run on a VPS/VM for 24/7 monitoring.
— Tech Stack

Built on reliable primitives.

No magic dependencies. Each piece chosen for reliability and ease of self-hosting.

Node.js + Express
React + TypeScript
SQLite
SSE Real-Time
Docker Multi-Stage
SMTP Alerts
Why SQLite?
Zero setup — database is just a file
Automatic cleanup keeps storage lean
Back up with a single cp command
No separate DB process or container
— Privacy-First

Your data never leaves your server.

Uptime data is operational intelligence. With Koala it stays on your infrastructure — always.

Zero data sent to third-party servers
No analytics, no tracking, no telemetry
Run fully air-gapped or on a private network
Open source, audit every line of code
Your SLA data stays strictly internal
∞
Data retention, on your terms
0
External calls
$0
Monthly SaaS fee
None
Vendor dependency
~2 min
Setup time
GET /events — SSE stream
12:04:01200api/health42ms
12:04:31101ws/stream18ms
12:05:01200api/health38ms
12:05:31504api/v2/users8210ms
12:06:01200api/health44ms
streaming...
— Real-Time

Live updates via Server-Sent Events.

No page refreshes. No polling. Koala streams check results to your dashboard the moment they happen.

Instant status transitions
Green to red in under a second. No refresh needed.
Rolling line charts
30-check latency history per endpoint as a live line chart.
Multi-protocol
HTTP, HTTPS, WebSocket, and WSS — all in one dashboard.
— Get Started

Self-hosted. Lightweight.
Developer-first.

Deploy Koala in under two minutes. No account, no credit card, no SaaS subscription.

Test in Playground Self-Host with Docker

Open source · MIT License · No telemetry · 60MB image