Sloth review
A self-hosted tool for turning declarative SLOs into Prometheus rules and dashboards.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Sloth is an open-source tool that generates Prometheus recording and alerting rules from declarative service-level objective specifications. It is aimed at teams that already operate Prometheus-based monitoring and want SLO definitions to fit into their workflows, particularly Kubernetes teams managing SLOs declaratively. Distributed as a CLI and container images, it is self-hosted rather than a vendor-hosted service, so teams own the runtime and operational setup.
The main appeal is its SLO workflow: Sloth can generate SLI recording rules, SLO metadata, error-budget metrics, and multi-window, multi-burn-rate alerts for paging and tickets. It also validates specifications for GitOps and CI, which can help teams check SLO changes as part of their delivery process. A Grafana dashboard displays SLO state. Kubernetes CRDs and controller/operator mode support declarative management, while OpenSLO input, a plugin system for SLIs and SLOs, and a Go library offer additional ways to integrate Sloth into existing practices.
Sloth fits best where Prometheus, Grafana, and Kubernetes are already central to monitoring. Its open-source distribution avoids a vendor-hosted subscription model, but self-hosting means the team must handle deployment and ongoing operation; support channels are documentation and community. The tool is a focused generator and workflow aid, not a general hosted reliability platform. Teams seeking managed service delivery or broader observability capabilities should consider alternatives. For Kubernetes operators who want SLO configuration checked in and translated into Prometheus rules, Sloth's scope is a close match.
Sloth pros and cons
- Where it wins
- Generates recording rules, error-budget metrics, and multi-burn-rate alerts
- Validates SLO specifications for GitOps and CI workflows
- Supports Kubernetes CRDs, OpenSLO, Grafana, and plugins
- Where it doesn't
- Requires teams to operate it in a self-hosted environment
- Focused on Prometheus-based monitoring rather than hosted observability
- Support is through documentation and community
Sloth fact sheet, pricing and score →
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