head to head · open source
monolog vs Logstash
monolog has 21,405 GitHub stars, 1,910 forks, 3 open issues and last shipped yesterday. Logstash has 14,946 stars, 3,495 forks, 2,254 open issues and last shipped 2 days ago. monolog leads on adoption by 43% (21,405 vs 14,946 stars). monolog is written in PHP under MIT; Logstash is written in Java under a custom or non-standard licence. monolog has attracted 9% as many forks as stars, Logstash 23%. 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 | Logstash | |
|---|---|---|
| GitHub stars | ★ 21K | ★ 15K |
| License | MIT | Custom / other |
| Written in | PHP | Java |
| Last push | 2026-09-19 | 2026-09-18 |
| Forks | ⑂ 1.9K | ⑂ 3.5K |
| 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 Logstash if
- You want the Logstash feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Java
- You evaluated both and Logstash fits your workflow better
About monolog
Monolog is a logging library for PHP that sends log records to files, sockets, inboxes, databases, and various web services. It ships with the handlers, formatters, and processors needed to route records where they belong, and special handlers allow more advanced logging strategies than a single output stream. The library lives in the PHP ecosystem and is distributed through Packagist as monolog/monolog . It is released under the MIT license and has been developed for sixteen years, with more than twenty one thousand stars and roughly nineteen hundred forks on GitHub.
read the full monolog overview →
About Logstash
Logstash is a server side data processing pipeline that transports and processes logs, events, or other data. It is part of the Elastic Stack with Beats, Elasticsearch, and Kibana, and it sits in the Infrastructure & Operations / Monitoring & Observability category. The project uses Java and JRuby, and its topics describe it as an ETL framework for logging, real time processing, and streaming.
read the full Logstash overview →
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Frequently asked questions
Is monolog or Logstash more popular?
monolog has 21,405 GitHub stars and Logstash has 14,946. monolog has the larger community by that measure.
Are monolog and Logstash free?
Both are open source. monolog is licensed under MIT, and Logstash has no licence declared in this registry. Both are free to self-host.
What is the difference between monolog and Logstash?
monolog is written in PHP and Logstash in Java. 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 Logstash?
Choose monolog if you want the larger community (21,405 stars) or its MIT licence terms. Choose Logstash if its feature set, stack or Custom / other licence fits better. Both are self-hostable.