Apache Solr vs Vespa
A side-by-side comparison of two self-hosted search engines options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Apache Solr | Vespa |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 81 · Excellent | 91 · Excellent |
| Category | Search Engines | Search Engines |
| License | Apache-2.0 | Apache-2.0 |
| Language | Java | Java |
| Setup difficulty | Hard | Hard |
| Min. RAM | 1,024 MB | 4,096 MB |
| Deployment | docker, kubernetes, bare-metal | docker, kubernetes, bare-metal |
| GitHub stars | ★ 1,673 | ★ 7,107 |
| First released | 2006 | 2017 |
| Replaces | Elasticsearch, Algolia | Elasticsearch, Algolia |
What are Apache Solr and Vespa?
Apache Solr
Apache Solr is a highly reliable, scalable and fault-tolerant open-source search platform built on Apache Lucene. It powers full-text search, faceting and analytics for many large websites and applications.
- Lucene-powered full-text search
- Faceting and rich querying
- Distributed SolrCloud mode
- Extensive plugin ecosystem
Vespa
Vespa is an open-source platform for low-latency computation over large data sets, powering search, recommendation and AI applications. It combines storing, searching, ranking and organizing data.
- Combined search and ML ranking
- Vector and tensor computation
- Real-time indexing at scale
- Used for large recommendation systems
Apache Solr vs Vespa: key differences
Both projects are written in Java. Apache Solr is the lighter option, starting around 1,024 MB of RAM against 4,096 MB for Vespa. Apache Solr is the more established project (first released 2006), while Vespa arrived in 2017. Vespa has the considerably larger community, at 7,107 GitHub stars versus 1,673.
Why pick each one
Choose Apache Solr if…
- Mature and battle-tested
- Powerful faceting
Watch out for
- Configuration is complex
Choose Vespa if…
- Extremely powerful and scalable
- Built-in ML ranking
Watch out for
- Steep learning curve
- Heavy resource needs
Frequently asked questions
Is Apache Solr or Vespa better?
Neither is universally better. Vespa has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Apache Solr and Vespa free and open-source?
Yes. Apache Solr is licensed under Apache-2.0 and Vespa under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Apache Solr and Vespa with Docker?
Apache Solr: yes. Vespa: yes.
Which is lighter on resources, Apache Solr or Vespa?
Apache Solr has the smaller minimum footprint at 1,024 MB of RAM, compared to about 4,096 MB for Vespa. Real-world usage depends on library size, user count, and enabled features.