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Software · head to head

Fluent Bit vs Grafana Loki

Fluent Bit logo

Fluent Bit

Software

Fast and Lightweight Log Processor

From
Free
Rated
-
Full reviewWebsite
Grafana Loki logo

Grafana Loki

Software

Log Aggregation for Grafana Stack

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Fluent Bit fluent Bit ships over 100 built in plugins against more than 1,000 external plugins available for Fluentd, so fewer integrations exist out of the box; Grafana Loki grafana Cloud Logs Pro plan includes only 30-day retention; retention beyond 30 days requires Enterprise plan with minimum $25,000 annual commitment
  • They diverge on capability: Fluent Bit covers Log collection, Grafana Loki covers Log aggregation.

Where they differ

Only the attributes on which Fluent Bit and Grafana Loki actually diverge.

Attributes where Fluent Bit and Grafana Loki differ
AttributeFluent BitGrafana Loki
Pricing modelopen-sourcefreemium
PlatformsWeb, ApiSelf-hosted (open source), Managed (Grafana Cloud Logs), Enterprise (self-managed with support)
Founded20152014

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 Fluent Bit

  • Log collection
  • Lightweight processing
  • Data parsing
  • Event filtering

Only in Grafana Loki

  • Log aggregation
  • Label-based indexing
  • LogQL language
  • Cost-effective

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.

Fluent Bit

  • Lightweight log and metric forwarding from containers and edge devicesnot Grafana Loki
  • Kubernetes node level log collection with a small memory footprintnot Grafana Loki
  • Filtering and enriching telemetry before shipping it to a backendnot Grafana Loki

Grafana Loki

  • Cost-sensitive organisations deploying Kubernetes and Prometheus ecosystemsnot Fluent Bit
  • Teams needing index-free log aggregation for high-volume environmentsnot Fluent Bit

Where each one falls short

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

Fluent Bit

  • Fluent Bit ships over 100 built in plugins against more than 1,000 external plugins available for Fluentd, so fewer integrations exist out of the box
  • It is written in C, so extending it beyond the built in plugins means writing C rather than Ruby
  • Dependencies are zero only until a plugin requires one

Grafana Loki

  • Grafana Cloud Logs Pro plan includes only 30-day retention; retention beyond 30 days requires Enterprise plan with minimum $25,000 annual commitment
  • Open-source version requires self-hosting all infrastructure including storage and scaling

Pricing, plan by plan

Fluent Bit

Free
  • FreeFree
    • Log collection
    • Lightweight processing
    • Data parsing

Grafana Loki

Free

No published plan breakdown. See the Grafana Loki review.

Which should you pick?

Choose Fluent Bit if

  • You need log collection.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want lightweight processing.
Fluent Bit review

Choose Grafana Loki if

  • You need log aggregation.
  • You want to start without paying.
  • You work on Self-hosted (open source), Managed (Grafana Cloud Logs), Enterprise (self-managed with support).
  • You also want label-based indexing.
Grafana Loki review

Questions people ask

Is Fluent Bit or Grafana Loki better?
Neither clearly leads. Fluent Bit starts at Free and Grafana Loki at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fluent Bit or Grafana Loki?
Fluent Bit starts at Free and Grafana Loki at Free.
Does Fluent Bit or Grafana Loki run on more platforms?
Fluent Bit runs on Web, Api. Grafana Loki runs on Self-hosted (open source), Managed (Grafana Cloud Logs), Enterprise (self-managed with support).
Can I use Fluent Bit for free?
Both have a free tier, so you can try either at no cost before committing.
What is Fluent Bit best used for?
Fluent Bit is most often used for lightweight log and metric forwarding from containers and edge devices, kubernetes node level log collection with a small memory footprint, filtering and enriching telemetry before shipping it to a backend. Of those, lightweight log and metric forwarding from containers and edge devices and kubernetes node level log collection with a small memory footprint are not what Grafana Loki is typically brought in for.
What can Fluent Bit do that Grafana Loki cannot?
Fluent Bit covers Log collection, Lightweight processing, Data parsing, Event filtering. Grafana Loki covers Log aggregation, Label-based indexing, LogQL language, Cost-effective. Both handle API, Webhooks, REST, Web support.
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