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Software · head to head

Azure Monitor vs Prometheus

Azure Monitor logo

Azure Monitor

Software

Azure's Monitoring and Diagnostics Service

From
Free
Rated
-
Full reviewWebsite
Prometheus logo

Prometheus

Software

Open source monitoring and alerting toolkit for cloud native environments

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Azure Monitor billed per GB ingested across three separate log plans, Auxiliary, Basic and Analytics, so the plan chosen changes the rate as much as the volume does; Prometheus not suitable for per-request billing as collected data lacks 100% accuracy
  • They diverge on capability: Azure Monitor covers Log collection, Prometheus covers Multi-dimensional Data Model.

Where they differ

Only the attributes on which Azure Monitor and Prometheus actually diverge.

Attributes where Azure Monitor and Prometheus differ
AttributeAzure MonitorPrometheus
Pricing modelusage-basedopen-source
PlatformsWeb, ApiLinux, macOS, Windows
Founded20102015

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Unknown).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Azure Monitor

  • Log collection
  • Metrics collection
  • Alerts and notifications
  • Custom dashboards
  • API
  • Webhooks
  • REST
  • Web support

Only in Prometheus

  • Multi-dimensional Data Model
  • PromQL Query Language
  • Pull-based Collection
  • Service Discovery
  • Alerting Rules
  • Federation
  • Local Storage
  • Grafana

What people use each for

The jobs each tool is most often brought in to do.

Azure Monitor

  • Collecting logs and metrics from Azure resourcesnot Prometheus
  • Alerting on metric thresholds and log queriesnot Prometheus
  • Application performance monitoring through Application Insightsnot Prometheus
  • Long-term log retention for compliancenot Prometheus
  • Querying operational data with KQLnot Prometheus

Prometheus

  • Cloud-native monitoring and alertingnot Azure Monitor
  • Time-series metrics collectionnot Azure Monitor
  • Infrastructure monitoringnot Azure Monitor

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Azure Monitor

  • Billed per GB ingested across three separate log plans, Auxiliary, Basic and Analytics, so the plan chosen changes the rate as much as the volume does
  • Only the first 5 GB a month of Analytics logs is free per billing account
  • Retention beyond the base period is charged per GB per month, up to 2 years interactive and 12 years long term
  • Log queries and search jobs are billed per GB scanned, so investigating an incident costs money
  • Alert rules are billed per time series for metrics and by execution frequency for logs
  • The pricing page shows placeholders rather than rates until a region and currency are chosen

Prometheus

  • Not suitable for per-request billing as collected data lacks 100% accuracy
  • Hard limit on scrape body size; large responses cause scrape failure
  • Per-scrape sample limit enforced; exceeding limit marks targets as failed
  • Not designed for long-term durable storage; optimised for metrics collection

Pricing, plan by plan

Azure Monitor

Free
  • FreeFree
    • Log collection
    • Metrics collection
    • Alerts and notifications

Prometheus

Free

No published plan breakdown. See the Prometheus review.

Which should you pick?

Choose Azure Monitor if

  • You need log collection.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want metrics collection.
Azure Monitor review

Choose Prometheus if

  • You need multi-dimensional data model.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want promql query language.
Prometheus review

Questions people ask

Is Azure Monitor or Prometheus better?
Neither clearly leads. Azure Monitor starts at Free and Prometheus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Azure Monitor or Prometheus?
Azure Monitor starts at Free and Prometheus at Free.
Does Azure Monitor or Prometheus run on more platforms?
Azure Monitor runs on Web, Api. Prometheus runs on Linux, macOS, Windows.
Can I use Azure Monitor for free?
Both have a free tier, so you can try either at no cost before committing.
What is Azure Monitor best used for?
Azure Monitor is most often used for collecting logs and metrics from azure resources, alerting on metric thresholds and log queries, application performance monitoring through application insights, long-term log retention for compliance. Of those, collecting logs and metrics from azure resources and alerting on metric thresholds and log queries are not what Prometheus is typically brought in for.
What can Azure Monitor do that Prometheus cannot?
Azure Monitor covers Log collection, Metrics collection, Alerts and notifications, Custom dashboards. Prometheus covers Multi-dimensional Data Model, PromQL Query Language, Pull-based Collection, Service Discovery.
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