Is Komga Down? Real-Time Status & Outage Checker

Komga is an open-source comics and manga server with 4,000+ GitHub stars, written in Kotlin and built on Spring Boot. It supports CBZ, CBR, PDF, and EPUB formats and features a web reader, OPDS feed for e-reader apps, Kobo sync, reading progress tracking, and comprehensive series management. Created by Gauthier Roebroeck, Komga exposes a full REST API for integrations and provides a mobile-friendly interface. It serves as a self-hosted alternative to Comixology and Marvel Unlimited — used by digital comic collectors who want full control over their libraries without DRM restrictions or subscription fees.

When Komga goes down, every e-reader and comic app that syncs via OPDS loses access simultaneously, reading progress stops syncing, and ongoing Kobo sync sessions fail mid-transfer. Because Komga runs on the JVM and often hosts large libraries on network storage, JVM out-of-memory events and storage unmounts are the most common — and most disruptive — failure modes.

Quick Status Check

#!/bin/bash
# Komga health check script
# Tests Spring Boot actuator, API, process, port, and library storage path

KOMGA_URL="${KOMGA_URL:-http://localhost:8080}"
KOMGA_USER="${KOMGA_USER:-admin@example.com}"
KOMGA_PASS="${KOMGA_PASS:-password}"
LIBRARY_PATH="${LIBRARY_PATH:-/comics}"

echo "=== Komga Health Check ==="

# 1. Check JVM/Java process
if pgrep -f "komga\|java" &>/dev/null; then
  echo "[OK] Komga JVM process is running"
else
  echo "[FAIL] Komga JVM process not detected"
fi

# 2. Check port 8080
if nc -z localhost 8080 2>/dev/null; then
  echo "[OK] Port 8080 is open"
else
  echo "[FAIL] Port 8080 is not responding"
fi

# 3. Spring Boot actuator health endpoint
HEALTH=$(curl -sf "${KOMGA_URL}/actuator/health" 2>/dev/null)
if echo "$HEALTH" | grep -q '"UP"'; then
  echo "[OK] Spring Boot actuator reports UP"
else
  echo "[FAIL] Actuator health check failed: ${HEALTH:0:120}"
fi

# 4. Library count via authenticated API
LIB=$(curl -sf \
  -u "${KOMGA_USER}:${KOMGA_PASS}" \
  "${KOMGA_URL}/api/v1/libraries" 2>/dev/null)
if echo "$LIB" | grep -q '"id"'; then
  LIB_COUNT=$(echo "$LIB" | python3 -c "import sys,json; print(len(json.load(sys.stdin)))" 2>/dev/null)
  echo "[OK] API authenticated — ${LIB_COUNT} library/libraries configured"
else
  echo "[FAIL] Authenticated API call failed: ${LIB:0:120}"
fi

# 5. Check library storage path
if [ -d "$LIBRARY_PATH" ]; then
  FILE_COUNT=$(find "$LIBRARY_PATH" -maxdepth 3 -name "*.cbz" -o -name "*.cbr" -o -name "*.pdf" 2>/dev/null | wc -l)
  echo "[OK] Library path accessible (${FILE_COUNT} comic file(s) found)"
else
  echo "[FAIL] Library path not accessible: $LIBRARY_PATH"
fi

echo "=== Check complete ==="

Python Health Check

#!/usr/bin/env python3
"""
Komga health check
Checks actuator health, library count, series count, book count, and storage paths.
"""

import os
import sys
import requests
from requests.auth import HTTPBasicAuth

KOMGA_URL = os.environ.get("KOMGA_URL", "http://localhost:8080")
KOMGA_USER = os.environ.get("KOMGA_USER", "admin@example.com")
KOMGA_PASS = os.environ.get("KOMGA_PASS", "password")
TIMEOUT = 15

AUTH = HTTPBasicAuth(KOMGA_USER, KOMGA_PASS)

def check(label: str, ok: bool, detail: str = "") -> bool:
    status = "OK  " if ok else "FAIL"
    msg = f"[{status}] {label}"
    if detail:
        msg += f" — {detail}"
    print(msg)
    return ok

results = []

# 1. Spring Boot actuator health (no auth required by default)
try:
    r = requests.get(f"{KOMGA_URL}/actuator/health", timeout=TIMEOUT)
    data = r.json() if r.status_code == 200 else {}
    ok = data.get("status") == "UP"
    results.append(check("Actuator health", ok, data.get("status", f"HTTP {r.status_code}")))
except Exception as e:
    results.append(check("Actuator health", False, str(e)))

# 2. Libraries configured
libraries = []
try:
    r = requests.get(f"{KOMGA_URL}/api/v1/libraries", auth=AUTH, timeout=TIMEOUT)
    ok = r.status_code == 200
    libraries = r.json() if ok else []
    count = len(libraries)
    ok = ok and count > 0
    results.append(check("Libraries configured", ok, f"{count} library/libraries"))
except Exception as e:
    results.append(check("Libraries configured", False, str(e)))

# 3. Series count
try:
    r = requests.get(
        f"{KOMGA_URL}/api/v1/series",
        auth=AUTH,
        params={"page": 0, "size": 1},
        timeout=TIMEOUT,
    )
    ok = r.status_code == 200
    data = r.json() if ok else {}
    total = data.get("totalElements", 0)
    results.append(check("Series accessible", ok, f"{total} series in library"))
except Exception as e:
    results.append(check("Series accessible", False, str(e)))

# 4. Book count
try:
    r = requests.get(
        f"{KOMGA_URL}/api/v1/books",
        auth=AUTH,
        params={"page": 0, "size": 1},
        timeout=TIMEOUT,
    )
    ok = r.status_code == 200
    data = r.json() if ok else {}
    total = data.get("totalElements", 0)
    results.append(check("Books accessible", ok, f"{total} book(s) total"))
except Exception as e:
    results.append(check("Books accessible", False, str(e)))

# 5. Storage path check via library metadata
if libraries:
    for lib in libraries:
        lib_name = lib.get("name", "unknown")
        lib_root = lib.get("root", "")
        if lib_root:
            path_ok = os.path.isdir(lib_root)
            results.append(check(
                f"Library storage: {lib_name}",
                path_ok,
                f"{lib_root} — {'accessible' if path_ok else 'NOT FOUND — may be unmounted'}"
            ))
else:
    results.append(check("Library storage paths", False, "no libraries returned to check"))

# Summary
passed = sum(results)
total = len(results)
print(f"\n{'='*40}")
print(f"Komga health: {passed}/{total} checks passed")
if passed < total:
    print("Action required: review FAIL items above")
    sys.exit(1)
else:
    print("All systems operational")
    sys.exit(0)

Common Komga Outage Causes

Architecture Overview

Uptime History

Monitor Komga Automatically

Komga is often the silent backbone of an entire household's comic reading setup — when the JVM crashes or the NAS unmounts at 2am, nobody knows until they pick up their Kobo or tablet and find empty shelves. External monitoring closes that gap immediately. ezmon.com monitors your Komga endpoints from multiple external probes and alerts your team via Slack, PagerDuty, or SMS the moment the Spring Boot actuator stops reporting UP or the API becomes unreachable.

Set up Komga monitoring free at ezmon.com →