#1★ TOP PICK
Grafana + Prometheus
The open-source observability standard.
90
OPEN SOURCEAGPL-3.0 (Grafana) / Apache-2.0 (Prometheus)SELF-HOSTLOCAL-FIRST
Prometheus scrapes and stores metrics; Grafana visualizes them (and logs and traces via Loki and Tempo). Together they are the de-facto open-source monitoring stack, fully self-hostable.
Strengths
- +Industry-standard, huge ecosystem
- +Metrics, logs, and traces via the same UI
- +Enormous community and dashboards
Trade-offs
- −You assemble and operate the stack
- −Steeper initial setup than a SaaS agent
#2
SigNoz
An OpenTelemetry-native, single-app Datadog alternative.
88
OPEN SOURCEMIT (core)SELF-HOSTLOCAL-FIRST
SigNoz brings metrics, traces, and logs into one open-source application built natively on OpenTelemetry, so you get APM-style visibility without per-host SaaS pricing.
Strengths
- +One app for traces, metrics, and logs
- +OpenTelemetry-native
- +Purpose-built as a Datadog replacement
Trade-offs
- −Younger ecosystem than Grafana
- −Self-hosting needs a datastore to operate
Free / self-host; optional managed cloud #3
Netdata
Real-time, per-second monitoring with zero-config auto-discovery.
85
OPEN SOURCEGPL-3.0SELF-HOSTLOCAL-FIRST
Netdata delivers high-resolution, real-time metrics with automatic discovery and minimal configuration, ideal for fast, granular infrastructure visibility on your own machines.
Strengths
- +Per-second resolution out of the box
- +Auto-discovers most services
- +Very low setup effort
Trade-offs
- −Less of a long-term query store than Prometheus
- −Best paired with other tools for logs/traces
Free / self-host; optional paid cloud