head to head · open source
monolog vs slog
monolog has 21,402 GitHub stars, 1,920 forks, 3 open issues and last shipped 3 days ago. slog has 1,706 stars, 98 forks, 57 open issues and last shipped 5 months ago. monolog leads on adoption by 1,155% (21,402 vs 1,706 stars). monolog is written in PHP under MIT; slog is written in Rust under Apache-2.0. monolog has attracted 9% as many forks as stars, slog 6%. monolog was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (logging), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| monolog | slog | |
|---|---|---|
| GitHub stars | ★ 21K | ★ 1.7K |
| License | MIT | Apache-2.0 |
| Written in | PHP | Rust |
| Last push | 2026-11-01 | 2026-06-01 |
| Forks | ⑂ 1.9K | ⑂ 98 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick monolog if
- You weight community size — 21K stars and counting
- You want the MIT license terms
- Your stack matches PHP
- You value the larger contributor base for long-term maintenance
pick slog if
- You want the slog feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and slog fits your workflow better
About monolog
Monolog Logging for PHP Note This is the documentation for Monolog 3.x , if you are using older releases see the documentation for Monolog 2.x or Monolog 1.x Monolog sends your logs to files, sockets, inboxes, databases and various web services. See the complete list of handlers below. Special handlers allow you to build advanced logging strategies. This library implements the PSR 3 interface that you can type hint against in your own libraries to keep a maximum of interoperability. You can also use it in your applications to make sure you can always use another compatible logger at a later time. As of 1.11.0…
read the full monolog overview →
About slog
Getting started Introduction FAQ Crate list slog rs The Logging for [Rust][rust] You might consider using tracing instead It's been a while since slog was created and it served Rust community well all this time. It remains a stable, featureful and battle tested library, used in many important projects. In last few years, another ecosystem for Rust was created with similar features and a very good support for debugging async code and already larger dev team and community. Please check tracing and see if it is more suitable for your use case. It seems that it is already a go to logging/tracing solution for Rust…
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Frequently asked questions
Is monolog or slog more popular?
monolog has 21,402 GitHub stars and slog has 1,706. monolog has the larger community by that measure.
Are monolog and slog free?
Both are open source. monolog is licensed under MIT and slog under Apache-2.0. Neither carries a licence fee.
What is the difference between monolog and slog?
monolog is written in PHP and slog in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, monolog or slog?
Choose monolog if you want the larger community (21,402 stars) or its MIT licence terms. Choose slog if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.