timbre
Timbre is a pure Clojure/ClojureScript logging library that eliminates Java logging complexity with configuration via simple Clojure data structures. It provides built-in appenders, middleware, rate limiting, and async logging out of the box.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | taoensso/timbre |
| Owner | taoensso |
| Primary language | Clojure |
| License | EPL-1.0 — Requires review (not clearly OSI) |
| Stars | 1.5k |
| Forks | 174 |
| Open issues | 4 |
| Latest release | v6.8.0 (2025-08-21) |
| Last updated | 2025-11-06 |
| Source | https://github.com/taoensso/timbre |
What timbre is
Timbre implements a functional logging model with appenders (fn [data] -> ?effects) and middleware (fn [data] -> ?data), supporting compile-time level/namespace elision, SLF4J interop, and cross-platform ClojureScript execution. The library includes configurable filtering, async queues, and raw argument capture for database persistence.
Get the timbre source
Clone the repository and explore it locally.
git clone https://github.com/taoensso/timbre.gitcd timbre# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Requires fluency in Clojure data structures and the functional appender/middleware model; Java developers unfamiliar with Clojure will need ramp-up time.
- Compile-time elision depends on correct linting configuration; misconfiguration may leave unexpected logging overhead in compiled code.
- Async appenders and rate limiting introduce queue management and backpressure considerations; proper tuning needed for high-volume logging.
- SLF4J interop is optional; existing tools.logging or Java logging integration must be explicitly configured.
- ClojureScript logging differs from Clojure (browser console output, no file appenders by default); dual-runtime testing required.
When to avoid it — and what to weigh
- Java-first or polyglot teams — Organizations deeply invested in Java logging ecosystems (Logback, Log4j) or requiring all team members to configure logging via standards may find Timbre's Clojure-specific approach limiting.
- Non-Clojure JVM languages — Timbre is not a general-purpose JVM logger; Scala, Kotlin, or Java projects should use established JVM logging frameworks.
- Enterprise audit/compliance-first logging — If your primary requirement is pre-built, certified compliance appenders (e.g., for healthcare, finance) and formal support contracts, Timbre may lack out-of-the-box solutions.
- Lightweight embedded or GraalVM constraints — Although GraalVM tests exist, runtime footprint and startup time in highly constrained environments may not be optimal compared to minimal loggers.
License & commercial use
Licensed under Eclipse Public License 1.0 (EPL-1.0), the same license as Clojure. EPL-1.0 is an OSI-approved, copyleft license requiring derivative works to be licensed under EPL-1.0 and providing explicit patent grants.
EPL-1.0 permits commercial use; however, any modifications or derivative works must also be licensed under EPL-1.0. Commercial users should review the full EPL-1.0 terms (particularly reciprocal license obligations) and consult legal counsel if creating proprietary derivative works.
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 | Good |
| Assessment confidence | High |
No explicit security vulnerabilities or audits mentioned in the provided data. Standard considerations: (1) appender implementations must sanitize/filter sensitive data before output; (2) async queues and rate limiting do not guarantee data loss prevention under extreme load; (3) no built-in encryption for log transport; (4) custom appenders bear responsibility for secure storage/transmission. Requires review of appender implementations for your use case.
Alternatives to consider
Telemere
Author's modern rewrite of Timbre; recommended for new Clojure projects. Likely offers refined API, performance improvements, and updated integrations; migration documented but requires code changes.
Logback / SLF4J (Java ecosystem)
Industry-standard JVM logging framework with extensive integrations, vendor support, and mature tooling; better fit for polyglot or Java-first teams.
tools.logging
Lighter-weight Clojure facade over SLF4J; simpler configuration if you prefer delegating to Java logging infrastructure rather than a pure Clojure implementation.
Build on timbre with DEV.co software developers
Timbre brings Clojure-native logging with built-in appenders, rate limiting, and async support. Evaluate for your Clojure/ClojureScript stack today.
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timbre FAQ
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Can I use Timbre in a commercial product?
Does Timbre work in ClojureScript?
What is the performance overhead?
Software developers & web developers for hire
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Simplify Clojure logging—skip Java config headaches
Timbre brings Clojure-native logging with built-in appenders, rate limiting, and async support. Evaluate for your Clojure/ClojureScript stack today.