Riemann review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Riemann is self-hosted, open-source software for processing events from servers and applications, with a focus on monitoring distributed systems. Developers and operations teams can use it to detect service and host state changes, combine event streams, and forward results to notification or metrics systems. Its configuration is executable Clojure code, making it a better fit for teams that want to define custom stream logic than for buyers seeking a point-and-click alerting service.

The processing model is the main draw. Riemann ingests events over Protocol Buffers using TCP or UDP, then supports composable filtering, transformation, and combination. It can track indexed event state with TTL-based expiration, detect state transitions, and use rollups and throttling to reduce notification volume. Configured streams can send email, SMS, or phone alerts, including PagerDuty alerts, while Graphite and Librato Metrics forwarding supports metrics workflows. A web dashboard provides querying and visualization of event state. This breadth within event processing makes Riemann useful when alert behavior needs to be expressed as code rather than assembled from fixed rules.

The tradeoff is operational and ecosystem fit. Teams need to self-host Riemann and be comfortable maintaining a Clojure-based configuration; it is not presented as a hosted commercial service. Its listed integrations include PagerDuty, Graphite, and Librato Metrics, alongside its event transports, so organizations relying on a wider set of ready-made alert destinations may prefer a product with a broader integration catalog. Choose Riemann for programmable, self-managed alert streams; look elsewhere if hosted operation, visual configuration, or extensive out-of-the-box integrations are priorities.

Riemann pros and cons

• Where it wins
  • Composable streams filter, transform, and combine incoming events.
  • State transitions, rollups, throttling, and TTLs help manage alert volume.
  • Forwards alerts and metrics, with a dashboard for querying event state.
• Where it doesn't
  • Configuration as Clojure code is a poor fit for teams seeking no-code setup.
  • Self-hosted deployment requires teams to operate the software themselves.
  • Its listed integrations are narrower than a broad alert-management ecosystem.

Riemann fact sheet, pricing and score →

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Last updated 7 Oct 2026 · How we research and update