ntfy-logging

ntfy notifications for the JVM: a framework-neutral engine with zero-code adapters for java.util.logging, Logback, Spring Boot and Micronaut, a one-line Log4j2 appender, a native-ready Quarkus extension, and a plain programmatic client.

Publish your application's ERROR-level log events as ntfy push notifications — and, if you opt in, WARN-level ones to a topic of their own. The engine is:

• storm-resistant — rate-limited with a count-never-lost suppressed-count digest, so a burst of errors collapses into one follow-up notification instead of flooding your topic;
• loop-safe — it never logs its own diagnostics back through the logging pipeline it publishes from, so a failure inside the notifier can never trigger itself;
• non-blocking by default — delivery is offloaded to a bounded queue drained by a daemon worker (the first-class alternative to hand-wrapping an AsyncAppender), so a slow or unreachable ntfy server never back-pressures your application threads during an error storm (async=false restores synchronous delivery);
• early — the JUL, Logback, Log4j2 and Quarkus adapters install through the logging framework itself, so alerting is live before your Spring ApplicationContext (or any DI container) exists — exactly the startup window where early fatal errors are otherwise invisible;
• verifiable at boot — an opt-in startup-ping self-test makes one real round-trip when the engine starts and reports a clear diagnostic ("the token may be revoked or expired", "url must be the base url with the topic NOT appended"), so a broken alerting config is found at deploy time instead of when the first real error silently fails to deliver;
• GraalVM-native ready — the Quarkus extension builds its HTTP client at runtime-init, and ntfy-core ships native-image metadata for hand-rolled native builds.

Pick your stack

Each library has its own guide with the dependency snippet, the Maven Central link, and the base config to get error alerts publishing:

Guide	Artifact	The 30-second version
Spring Boot	ntfy-spring-boot-starter	Add the starter, set ntfy.url/ntfy.topic in application.yml — error logs auto-publish; @Autowired NtfyClient for manual ones.
Quarkus	ntfy-quarkus-runtime	Add the extension, set quarkus.ntfy.url/.topic — error logs auto-publish (native-ready); @Inject NtfyClient for manual ones.
Micronaut	ntfy-micronaut	Add the module, set ntfy.url/ntfy.topic in application.yml — error logs auto-publish on the Logback root logger; @Inject NtfyClient for manual ones.
Plain Logback	ntfy-logback	Add the appender, set NTFY_URL/NTFY_TOPIC — zero-code auto-install, or wire it explicitly in logback.xml.
Plain Log4j2	ntfy-log4j2	Add the appender, set NTFY_URL/NTFY_TOPIC — declare <Ntfy .../> in log4j2.xml, or NtfyLog4j2Installer.install() in main.
java.util.logging	ntfy-jul	Add the handler, set NTFY_URL/NTFY_TOPIC — declare it in logging.properties, or NtfyJulInstaller.install() in main.
Core	ntfy-core	Build a NtfyConfig, drive NtfyClient yourself from any JVM app.

Each module pulls ntfy-core transitively — you only ever declare the one that matches your stack. Everything beyond the base config — the full key reference, authentication, alert behavior, level routing, filtering, MDC context, observability, troubleshooting, compatibility and the BOM — is shared across all seven and listed in the sidebar.

API documentation

The aggregated Javadoc for every published module is part of this site, versioned alongside it:

Browse the Javadoc

Runnable examples

Every adapter has a small, realistic example application, and the guides above embed their real configuration files directly. They are not illustrations: their integration tests boot the example apps against a loopback ntfy stand-in in CI — covering the base alert path, the synchronous-vs- asynchronous delivery difference, and the clean-shutdown digest flush — so the examples on this site can never drift from the code.