How to self-host your Datadog alternative
"Datadog" is a brand that bundles several distinct functions — dashboards, error tracking, traces, infrastructure monitoring — as one product. None of this catalog's alternatives covers all of them with the same depth, so the real question isn't "which one replaces Datadog" but "which part of Datadog do I need to replace."
Tools that meet this intent
Alternative to Datadog
Observability dashboards, a self-hosted alternative to Datadog.
Alternative to Bugsnag, Datadog
Production error tracking, the official self-hosted version.
Alternative to Datadog, New Relic
Unified metrics + traces + logs, an alternative to Datadog/New Relic.
Alternative to Datadog, New Relic
Ultra-lightweight server monitor, a single binary, a minimal alternative to Datadog.
Real server requirements
Between 256MB and 4GB of RAM depending on the tool — never a single number.
Grafana is just the visualization layer — the project itself says so: you need Prometheus, Loki or Tempo separately to have any data to show. Sentry (self-hosted) is the official error-tracking and application performance (APM) server, with a heavy stack behind it (Postgres, Redis, Kafka and ClickHouse) installed via its own script, not a loose Docker image. SigNoz unifies metrics, traces and logs in one panel, built on OpenTelemetry, also on top of ClickHouse. Beszel covers only infrastructure — CPU, RAM, disk, network across your servers — as a single binary with no dependencies; the project itself is clear that it does no application error tracking.
If what you want from Datadog is "see errors in production," Sentry is the direct match. If it's "see metrics and traces," SigNoz. If it's "a dashboard over data I already collect some other way," Grafana. If it's "know when a server is running low on RAM," Beszel — these are different pieces, not different sizes of the same thing.
What you gain and lose versus the SaaS
About Sentry: even though its code is publicly available, its license (FSL-1.1) isn't a classic FOSS or Open-Core license — it carries its own conditions around distribution. It isn't "just open source," and if you need to know exactly what it permits before using it, check the full terms at the official source rather than assuming anything from the name. About the rest: none of the 4 replaces Datadog wholesale — combining several is normal, and picking "the most complete one" (SigNoz) doesn't spare you from deciding whether you also need the error tracking that only Sentry covers.