Lunr.js vs Sonic
A side-by-side comparison of two self-hosted search engines options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Lunr.js | Sonic |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Health score | 29 · At risk | 96 · Excellent |
| Category | Search Engines | Search Engines |
| License | MIT | MPL-2.0 |
| Language | JavaScript | Rust |
| Setup difficulty | Easy | Medium |
| Min. RAM | 64 MB | 32 MB |
| Deployment | source | docker, binary |
| GitHub stars | ★ 9,203 | ★ 21,349 |
| First released | 2013 | 2019 |
| Replaces | Algolia, Elasticsearch | Algolia, Elasticsearch |
What are Lunr.js and Sonic?
Lunr.js
Lunr.js is a small, full-text search library for use in the browser that provides a simple search index without needing a backend service. It is commonly used to add offline search to static sites and documentation.
- Browser-based search
- No backend needed
- Prebuilt index support
- Tiny library size
Sonic
Sonic is a fast, lightweight and schema-less search backend that can be used as a simpler, more efficient alternative to Elasticsearch. It is designed to ingest and query text with minimal resources.
- Extremely low memory usage
- Schema-less ingestion
- Fast prefix and word search
- Simple text protocol
Lunr.js vs Sonic: key differences
Lunr.js is written in JavaScript, while Sonic is built with Rust. Licensing differs — MIT for Lunr.js versus MPL-2.0 for Sonic. Sonic is the lighter option, starting around 32 MB of RAM against 64 MB for Lunr.js. Lunr.js is the more established project (first released 2013), while Sonic arrived in 2019. Sonic has the considerably larger community, at 21,349 GitHub stars versus 9,203. Sonic lists first-class Docker deployment; Lunr.js does not.
Why pick each one
Choose Lunr.js if…
- Released under the MIT license
- Easy to set up — beginner-friendly
- Mature project with 9.2k GitHub stars
- Written in JavaScript
Choose Sonic if…
- Tiny resource footprint
- Very fast for autocomplete
Watch out for
- No relevance scoring or filtering
Frequently asked questions
Is Lunr.js or Sonic better?
Neither is universally better. Sonic has the larger community, while Lunr.js is simpler to set up (easy difficulty). Choose based on the comparison table above and your own setup.
Are Lunr.js and Sonic free and open-source?
Yes. Lunr.js is licensed under MIT and Sonic under MPL-2.0. Both can be self-hosted at no software cost.
Can I run Lunr.js and Sonic with Docker?
Lunr.js: check the project docs for container support. Sonic: yes.
Which is lighter on resources, Lunr.js or Sonic?
Sonic has the smaller minimum footprint at 32 MB of RAM, compared to about 64 MB for Lunr.js. Real-world usage depends on library size, user count, and enabled features.