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Logging · head to head

Checkmk vs Fluentd

Checkmk logo

Checkmk

Logging

Comprehensive IT monitoring, open and flexible

From
Free
Free plan
Yes
Visit CheckmkFull review
Fluentd logo

Fluentd

Logging

Open Source Data Collector for Unified Logging

From
Free
Free plan
Yes
Visit FluentdFull review

The short version

  • Fluentd is an open-source data collector.
  • Fluentd is free; Checkmk starts at €190/mo.
  • Where Checkmk falls short: pricing calculated by service count, not hosts (approximately 30 services per host on average).
  • Where Fluentd falls short: Fluentd needs more than 60 MB of memory at runtime, against roughly 450 KB for Fluent Bit.
  • Prices and features on this page were last checked on 13 November 2026.

Where they differ

Only the attributes on which Checkmk and Fluentd actually diverge.

Attributes where Checkmk and Fluentd differ
AttributeCheckmkFluentd
Pricing modelSubscriptionOpen-source
PlatformsWebWeb, API

Identical on both: starting price (Free), free tier (Yes), category (Logging).

Not yet recorded: founded for Checkmk.

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 Checkmk

Nothing recorded that Fluentd does not also cover.

Only in Fluentd

  • Log collection
  • Data parsing
  • Filtering and buffering
  • Event routing
  • API
  • Webhooks
  • REST
  • Web support

What people use each for

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

Checkmk

  • Infrastructure monitoringnot Fluentd
  • System observabilitynot Fluentd
  • Enterprise compliance monitoringnot Fluentd

Fluentd

  • Unified log collection and routing from many sources to many destinationsnot Checkmk
  • Parsing and transforming log records before forwardingnot Checkmk
  • Aggregating logs from containers into Elasticsearch, S3 or a SIEMnot Checkmk

Where each one falls short

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

Checkmk

  • Pricing calculated by service count, not hosts (approximately 30 services per host on average)
  • Professional support limited to 8-10 hours per week on base plans
  • Synthetic monitoring is separate add-on with per-test pricing

Fluentd

  • Fluentd needs more than 60 MB of memory at runtime, against roughly 450 KB for Fluent Bit
  • Fluentd is built as a Ruby gem and depends on other gems, so a Ruby runtime is required
  • Its capability comes from over 1,000 external plugins rather than built in functionality, so each added input or output is a separate dependency
  • The Fluent Bit documentation states that cloud providers have switched from Fluentd to Fluent Bit for performance and compatibility and calls Fluent Bit the next generation solution

Pricing, plan by plan

Checkmk

Free
  • Community (Self-Hosted)Free
    • No cost, forever
    • Up to ~100 hosts
    • Basic infrastructure monitoring
  • Pro (Self-Hosted)€190/mo
    • Advanced analytics
    • Reporting
    • Distributed monitoring
  • Ultimate (Self-Hosted)€275/mo
    • Full-stack observability
    • Advanced security compliance
    • 10 hours x 5 days professional support (upgradable to 24/7)
  • CloudAI (SaaS)€240/mo
    • Fully managed cloud hosting
    • 99.5% uptime SLA
    • Supports up to 50000 services

Fluentd

Free
  • FreeFree
    • Log collection
    • Data parsing
    • Filtering and buffering

Which should you pick?

Choose Checkmk if

  • You want to start without paying.
Checkmk review

Choose Fluentd if

  • You need log collection.
  • You want to start without paying.
  • You work on Web, API.
  • You also want data parsing.
Fluentd review

Questions people ask

Is Checkmk or Fluentd better?
Neither clearly leads. Checkmk starts at Free and Fluentd at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Checkmk or Fluentd?
Checkmk starts at Free and Fluentd at Free.
Does Checkmk or Fluentd run on more platforms?
Checkmk runs on Web. Fluentd runs on Web, API.
Can I use Checkmk for free?
Both have a free tier, so you can try either at no cost before committing.
What is Checkmk best used for?
Checkmk is most often used for infrastructure monitoring, system observability, enterprise compliance monitoring. Of those, infrastructure monitoring and system observability are not what Fluentd is typically brought in for.
What can Checkmk do that Fluentd cannot?
Fluentd covers Log collection, Data parsing, Filtering and buffering, Event routing.

Answered from the vendors’ own pages

Checkmk: Is there a free version of Checkmk?

Yes, Checkmk Community edition is free forever and supports up to approximately 100 hosts for basic infrastructure monitoring with no cost.

Source
Fluentd: How much does Fluentd cost?

Fluentd is free and open-source under the Apache 2 License from the Cloud Native Computing Foundation (CNCF). There are no subscription fees, licensing costs, or commercial pricing tiers.

Source
Checkmk: How does Checkmk calculate pricing by host count?

Checkmk uses service-based pricing where each monitored aspect (file system, hardware sensor, switch port, metric) counts as one service. On average, there are approximately 30 services per host.

Source
Checkmk: What is the difference between Checkmk Pro and Ultimate tiers?

Pro tier at 190 EUR/month includes advanced analytics and 8x5 support, while Ultimate at 275 EUR/month adds full-stack observability, advanced compliance features, and upgradable 24/7 support.

Source
Checkmk: Does Checkmk offer a managed SaaS option?

Yes, Checkmk CloudAI is a fully managed SaaS tier at 240 EUR/month with 99.5% uptime SLA and support for up to 50000 services.

Source
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