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Logging · head to head

Fluentd vs Graylog

Fluentd logo

Fluentd

Logging

Open Source Data Collector for Unified Logging

From
Free
Rated
-
Full reviewWebsite
Graylog logo

Graylog

Logging

Log Aggregation and Analysis Platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Fluentd fluentd needs more than 60 MB of memory at runtime, against roughly 450 KB for Fluent Bit; Graylog graylog Enterprise starts at $15,000 per year and Graylog Security at $18,000 per year, priced by daily volume or annual consumption
  • They diverge on capability: Fluentd covers Log collection, Graylog covers Log aggregation.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Fluentd and Graylog actually diverge.

Attributes where Fluentd and Graylog differ
AttributeFluentdGraylog

Identical on both: starting price (Free), pricing model (open-source), free tier (Yes), platforms (Web, Api), user rating (Not yet rated), category (Logging), founded (2011).

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 Fluentd

  • Log collection
  • Data parsing
  • Filtering and buffering
  • Event routing

Only in Graylog

  • Log aggregation
  • Full-text search
  • Parsing and extraction
  • Real-time analytics

Both cover

  • API
  • Webhooks
  • REST
  • Web support
  • Api support

What people use each for

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

Fluentd

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

Graylog

  • Log aggregation and analysis for SecOps teamsnot Fluentd
  • IT and DevOps monitoring and troubleshootingnot Fluentd
  • Enterprise security event monitoringnot Fluentd

Where each one falls short

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

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

Graylog

  • Graylog Enterprise starts at $15,000 per year and Graylog Security at $18,000 per year, priced by daily volume or annual consumption
  • Correlation engine, scheduled and custom reports, compliance reports and teams management are Enterprise-only
  • Data tiering across hot, warm and archive storage is an Enterprise feature, not available in Graylog Open
  • Graylog Open carries community support only; professional support requires a paid edition
  • UEBA anomaly detection, Sigma rules, MITRE ATT&CK alignment and SOAR automation are limited to Graylog Security

Pricing, plan by plan

Fluentd

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

Graylog

Free
  • FreeFree
    • Log aggregation
    • Full-text search
    • Parsing and extraction

Which should you pick?

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

Choose Graylog if

  • You need log aggregation.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want full-text search.
Graylog review

Questions people ask

Is Fluentd or Graylog better?
Neither clearly leads. Fluentd starts at Free and Graylog at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fluentd or Graylog?
Fluentd starts at Free and Graylog at Free.
Does Fluentd or Graylog run on more platforms?
Both run on Web, Api, so platform support will not decide this one for you.
Can I use Fluentd for free?
Both have a free tier, so you can try either at no cost before committing.
What is Fluentd best used for?
Fluentd is most often used for unified log collection and routing from many sources to many destinations, parsing and transforming log records before forwarding, aggregating logs from containers into elasticsearch, s3 or a siem. Of those, unified log collection and routing from many sources to many destinations and parsing and transforming log records before forwarding are not what Graylog is typically brought in for.
What can Fluentd do that Graylog cannot?
Fluentd covers Log collection, Data parsing, Filtering and buffering, Event routing. Graylog covers Log aggregation, Full-text search, Parsing and extraction, Real-time analytics. Both handle API, Webhooks, REST, Web support.

Answered from the vendors’ own pages

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
Graylog: Does Graylog have a free version?

Yes. Graylog Open is a free, open-source option for collecting, storing, searching, and analyzing log data. However, it includes only community support.

Source
Graylog: How much does Graylog Enterprise cost?

Graylog Enterprise pricing starts at $15,000/year based on daily log volume or annual data consumption. Exact pricing requires contacting sales.

Source
Graylog: What is the difference between Graylog Enterprise and Security editions?

Graylog Security starts at $18,000/year and includes advanced threat detection capabilities beyond the Enterprise edition. Both include technical support.

Source
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