fluent-bit
Fluent Bit is a lightweight, open-source agent for collecting, processing, and forwarding logs, metrics, and traces from any source to any destination. It runs on Linux, Windows, macOS, BSD, and embedded systems with minimal resource overhead and supports 70+ built-in plugins for flexible data pipeline configuration.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | fluent/fluent-bit |
| Owner | fluent |
| Primary language | C |
| License | Apache-2.0 — OSI-approved |
| Stars | 8k |
| Forks | 1.9k |
| Open issues | 737 |
| Latest release | v5.0.9 (2026-07-04) |
| Last updated | 2026-07-08 |
| Source | https://github.com/fluent/fluent-bit |
What fluent-bit is
Written in C with a pluggable architecture, Fluent Bit provides unified telemetry collection (logs, metrics, traces) via input/filter/output pipelines, SQL-based stream processing, Lua filter scripting, TLS/SSL networking, and Prometheus metrics exposure. Extensible via C plugins, Lua filters, and Go outputs.
Get the fluent-bit source
Clone the repository and explore it locally.
git clone https://github.com/fluent/fluent-bit.gitcd fluent-bit# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Configuration via TOML/YAML with plugin-based pipeline model; test thoroughly in staging before production rollout due to plugin interdependencies.
- Memory footprint and CPU usage scale with data volume and filter complexity; monitor resource consumption to avoid pipeline bottlenecks.
- TLS/SSL support is built-in but requires proper certificate management and validation—ensure endpoint security is configured for sensitive data.
- Lua-based filters and SQL stream processing add flexibility but require development effort and testing; pre-built plugins cover common use cases.
- Version upgrades follow a 3–4 month release cycle; plan for regular updates to stay current with bug fixes and feature additions.
When to avoid it — and what to weigh
- Stateful, high-complexity transformations — If you need extensive stateful processing or complex machine-learning-based enrichment, consider Kafka Streams, Spark, or full Fluentd—Fluent Bit optimizes for lightweight forwarding, not heavy computation.
- Windows-only or proprietary OS ecosystems — While Fluent Bit supports Windows, its primary optimization focus is Linux/containerized workloads. Niche or proprietary OS platforms may lack community testing and support.
- Low community expertise with C/Lua plugin development — Custom plugin development requires C and potentially Lua proficiency. Teams without this skillset may face steep learning curves for advanced extensibility beyond built-in plugins.
- Guaranteed commercial SLA requirements without vendor support — Fluent Bit is community-maintained. Organizations requiring guaranteed SLAs, priority support, or long-term vendor backing should evaluate commercial Fluentd or paid observability platforms.
License & commercial use
Licensed under Apache License 2.0, a permissive OSI-approved license allowing commercial use, modification, and distribution with minimal restrictions (retain copyright/license notices, no liability).
Apache 2.0 permits commercial use without licensing fees or vendor permission. However, the project is community-maintained; organizations requiring commercial support contracts, guaranteed SLAs, or indemnification should evaluate commercial options or support partnerships (not stated in data provided—requires review with vendor).
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Active |
| Documentation | Strong |
| License clarity | Clear |
| Deployment complexity | Low |
| DEV.co fit | Strong |
| Assessment confidence | High |
Built-in TLS/SSL support and async I/O reduce attack surface for network communication. No security audit or vulnerability disclosure timeline mentioned in data. Standard open-source practices apply: review upstream dependencies, validate plugin sources, keep version current, and apply principle of least privilege for sidecar/agent permissions. Consider network segmentation and API endpoint authentication in deployment.
Alternatives to consider
Fluentd
Heavier, more feature-rich alternative in the same ecosystem. Preferred if you need extensive stateful transformations, Ruby plugin ecosystem, or require commercial support; less suitable for resource-constrained environments.
Filebeat / ELK Stack
Elasticsearch-focused lightweight shipper with strong Kubernetes integration and commercial backing. Better if you're committed to the ELK stack; less flexible for multi-destination, multi-format telemetry pipelines.
Telegraf (InfluxDB)
Lightweight metrics and logs collector focused on InfluxDB and time-series platforms. Better for metrics-first use cases; less suitable for complex multi-source, multi-destination log aggregation.
Build on fluent-bit with DEV.co software developers
Fluent Bit offers flexible, resource-efficient telemetry collection for Kubernetes and cloud-native environments. Evaluate fit for your architecture and deployment strategy with our technical team.
Talk to DEV.coRelated open-source tools
Surfaced by semantic similarity across the DEV.co open-source index.
Related on DEV.co
Explore the category and the services that help you build with it.
fluent-bit FAQ
Does Fluent Bit support Kubernetes logs collection?
Can I write custom plugins?
What is the performance overhead?
Is Fluent Bit suitable for mission-critical production?
Software development & web development with DEV.co
From first prototype to production, DEV.co delivers software development services around tools like fluent-bit. Our software development agency staffs experienced software developers and web developers for custom software development, web development, integrations, and ongoing support across open-source observability and beyond.
Ready to streamline your observability pipeline?
Fluent Bit offers flexible, resource-efficient telemetry collection for Kubernetes and cloud-native environments. Evaluate fit for your architecture and deployment strategy with our technical team.