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Logging · head to head

CloudWatch vs Fluentd

CloudWatch logo

CloudWatch

Logging

AWS Monitoring and Observability

From
Free
Rated
-
Full reviewWebsite
Fluentd logo

Fluentd

Logging

Open Source Data Collector for Unified Logging

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: CloudWatch the free tier covers 5 GB of log ingestion and 10 custom metrics a month, after which log ingestion is $0.50 per GB from 5 to 30 GB; Fluentd fluentd needs more than 60 MB of memory at runtime, against roughly 450 KB for Fluent Bit
  • They diverge on capability: CloudWatch covers Metrics collection, Fluentd covers Log collection.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which CloudWatch and Fluentd actually diverge.

Attributes where CloudWatch and Fluentd differ
AttributeCloudWatchFluentd
Pricing modelusage-basedopen-source
Founded20062011

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

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 CloudWatch

  • Metrics collection
  • Log aggregation
  • Dashboards
  • Alarms and notifications

Only in Fluentd

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

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.

CloudWatch

  • Metrics and log collection for AWS workloadsnot Fluentd
  • Alarming on thresholds across AWS servicesnot Fluentd
  • Querying logs with Logs Insightsnot Fluentd
  • Live tailing logs during an incidentnot Fluentd
  • Distributed tracing alongside X-Raynot Fluentd

Fluentd

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

Where each one falls short

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

CloudWatch

  • The free tier covers 5 GB of log ingestion and 10 custom metrics a month, after which log ingestion is $0.50 per GB from 5 to 30 GB
  • Custom metrics are $0.30 each for the first 10,000, so instrumenting broadly gets expensive before volume discounts apply
  • Each custom dashboard beyond the free three is $3 a month
  • Alarms are billed at $0.10 per alarm metric a month, with high-resolution alarms costing more
  • Log storage beyond the free 5 GB is $0.03 per GB per month on top of the ingestion charge

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

CloudWatch

Free
  • Pay-as-you-goFree
    • Logs ingestion: $0.50/GB (first 5GB free), down to $0.05/GB at scale
    • Logs storage: $0.03/GB/month
    • Live Tail: $0.01/minute after 1,800 free minutes
  • Free tierFree
    • 5GB logs ingestion per month
    • 10 custom metrics
    • 3 custom dashboards

Fluentd

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

Which should you pick?

Choose CloudWatch if

  • You need metrics collection.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want log aggregation.
CloudWatch 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 CloudWatch or Fluentd better?
Neither clearly leads. CloudWatch 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, CloudWatch or Fluentd?
CloudWatch starts at Free and Fluentd at Free.
Does CloudWatch or Fluentd run on more platforms?
Both run on Web, Api, so platform support will not decide this one for you.
Can I use CloudWatch for free?
Both have a free tier, so you can try either at no cost before committing.
What is CloudWatch best used for?
CloudWatch is most often used for metrics and log collection for aws workloads, alarming on thresholds across aws services, querying logs with logs insights, live tailing logs during an incident. Of those, metrics and log collection for aws workloads and alarming on thresholds across aws services are not what Fluentd is typically brought in for.
What can CloudWatch do that Fluentd cannot?
CloudWatch covers Metrics collection, Log aggregation, Dashboards, Alarms and notifications. Fluentd covers Log collection, Data parsing, Filtering and buffering, Event routing. Both handle API, Webhooks, REST, Web support.

Answered from the vendors’ own pages

CloudWatch: How much does Amazon CloudWatch cost?

CloudWatch uses pay-as-you-go pricing with no upfront commitment. Logs ingestion costs $0.50/GB (first 5GB free), logs storage is $0.03/GB/month, custom metrics cost $0.30/metric/month (first 10,000), custom dashboards are $3/month, and standard alarms are $0.10/metric/month.

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
CloudWatch: Does CloudWatch offer a free tier?

Yes, CloudWatch free tier includes 5GB logs ingestion, 10 custom metrics, 3 custom dashboards, and 10 alarm metrics per month at no charge. Usage beyond these limits incurs pay-as-you-go fees.

Source
CloudWatch: What are CloudWatch's pricing tiers for high-volume usage?

CloudWatch offers tiered pricing with volume discounts: logs ingestion starts at $0.50/GB and decreases to $0.05/GB at higher volumes; custom metrics start at $0.30/metric/month and decline to $0.05 at higher volumes; Application Signals cost $1.50 per million traces initially, declining to $0.30.

Source
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