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Fluent Bit

fluentbit.io

Free plan WindowsmacOSLinuxSelf-hosted
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Spec score 8.1 #13 of 28 in Telemetry Pipeline Software

What it is

Fluent Bit is a free, open-source telemetry agent for collecting and processing logs, metrics, and traces. It can run as an edge agent on constrained systems or as a central collector for cloud infrastructure, and is designed for high throughput with low resource consumption. Built-in parsers cover JSON, Regex, LTSV, and Logfmt; metrics compatibility includes Prometheus and OpenTelemetry. More than 100 built-in plugins cover inputs, filters, analytics, and outputs, with destinations including Splunk, Elasticsearch, OpenSearch, and Kafka. Buffering in memory or on the file system and backpressure handling support data flow, while network input and output plugins include TLS and SSL. Stream processing supports SQL queries, aggregation windows, forecasting, and data analysis. Users can write plugins in C, Lua, Golang, or WebAssembly. The Open-source Fluent Bit plan costs nothing, with self-hosted deployment under the Apache License 2.0. Official packages and installation guidance cover Linux, macOS, Windows, containers, and selected BSD and IBM Z Linux environments.

Spec sheet

Purpose
Fluent Bit is an open-source telemetry agent for collecting and processing telemetry across constrained systems and cloud infrastructures.Read 1 Oct 2026 · docs.fluentbit.io
Deployment
It can run as an edge agent or as a central aggregator or collector.Read 1 Oct 2026 · docs.fluentbit.io
Integrations
Output destinations include Splunk, Elasticsearch, OpenSearch, Kafka, and other services.Read 1 Oct 2026 · fluentbit.io
Security
Fluent Bit has integrated TLS and SSL support for network input and output plugins.Read 1 Oct 2026 · docs.fluentbit.io
License
Fluent Bit, its core, plugins, and tools are distributed under the Apache License 2.0.Read 1 Oct 2026 · docs.fluentbit.io
Founded
2014Read 28 Sep 2026 · fluentbit.io
Data types
Fluent Bit processes logs, metrics, and traces.Read 1 Oct 2026 · fluentbit.io
Extensibility
Users can write plugins in C, Lua, Golang, or WebAssembly.Read 1 Oct 2026 · docs.fluentbit.io
Metrics
Fluent Bit is compatible with Prometheus and OpenTelemetry metrics.Read 1 Oct 2026 · docs.fluentbit.io
Operating systems
Official packages and installation guidance cover Linux, macOS, Windows, containers, and selected BSD and IBM Z Linux environments.Read 1 Oct 2026 · docs.fluentbit.io
Parsing
Built-in parsers support JSON, Regex, LTSV, and Logfmt.Read 1 Oct 2026 · docs.fluentbit.io
Performance
The project is designed for high throughput with low resource consumption.Read 1 Oct 2026 · docs.fluentbit.io
Plugins
The project provides more than 100 built-in input, filter, analytics, and output plugins.Read 1 Oct 2026 · fluentbit.io
Reliability
It provides backpressure handling and buffering in memory and on the file system.Read 1 Oct 2026 · docs.fluentbit.io
Stream processing
Fluent Bit supports stream processing with SQL queries, aggregation windows, forecasting, and data analysis.Read 1 Oct 2026 · docs.fluentbit.io
Support limitation
Not all plugins and filters are supported on BSD systems or every other platform.Read 1 Oct 2026 · docs.fluentbit.io

Plans and prices

Open-source Fluent Bit Free Apache License 2.0 · self-hosted deployment Read 1 Oct 2026 · docs.fluentbit.io

Every Fluent Bit plan and price →

Strong points and limits

Strong points

  • Processes logs, metrics, and traces.
  • Offers more than 100 built-in plugins.
  • Supports memory and file-system buffering.
  • Plugins can be written in four listed languages.

Limits

  • Not all plugins and filters work on BSD or every platform.
  • Deployment is self-hosted.

Who it suits

Fluent Bit suits teams collecting telemetry across constrained systems or cloud infrastructure, whether at the edge or in a central collector. It may also fit users who need plugin-based routing and stream processing in a self-hosted, open-source agent.

Verdict

Fluent Bit covers collection, processing, buffering, and routing in a free, self-hosted package. Check platform support for the specific plugins and filters you need, particularly on BSD.

Where Specifiction places it

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