Apache Solr

Free plan Open source APILinuxMacSelf-hostedWebWindows

What Apache Solr is

Apache Solr is a free, self-hosted search platform built on Apache Lucene, with full-text, vector, and geospatial search capabilities. It accepts documents over HTTP in JSON, XML, CSV, or binary formats and returns results in those formats through a REST query interface. Matching options include phrases, wildcards, joins, and grouping; discovery tools include faceting, autocomplete, spelling suggestions, hit highlighting, and result clustering. Solr can distribute indexing, replicate data, balance queries across servers, and provide automated failover and recovery. It integrates Apache Tika to extract and process content from PDFs and Microsoft Word documents. Administrators can use its interface to control instances and inspect cluster state, logs, threads, and metrics. Listed security capabilities include SSL, authentication, and role-based authorization. Solr runs on Linux, macOS, and Windows, with API access, and is licensed under Apache License, Version 2.0. Community support is available through the users mailing list and other channels. Releases are not scheduled in advance; versions below 9.10 are end of life and will not receive further updates.

Who it suits

Solr suits teams that need self-hosted full-text, vector, or geospatial search, from small projects to enterprise applications. It also fits operators seeking distributed indexing and query management.

What it does well

Supports full-text, vector, and geospatial search.
Offers faceting, autocomplete, and result clustering.
Provides distributed indexing and automated failover.
Includes SSL, authentication, and role-based authorization.

What to know first

Release dates are not scheduled in advance.
Versions below 9.10 are end of life.

Limits

Solr is free, with no free-plan quota listed. Versions older than 9.10 are end of life and will not receive further updates; release timing is not scheduled in advance.

Plans

Plan	Billed and limits	Price
Apache Solr	Open-source search platform · binary and source releases · Apache License, Version 2.0	Free
Apache Solr Free	Source and binary releases · self-hosted deployment · no usage fee	Free

As solr.apache.org lists them, read 4 Oct 2026. The maker's own page has the final word.

Getting started

Visit https://solr.apache.org/.
Choose a binary or source release.
Select a Linux, macOS, or Windows environment for self-hosted deployment.
Send documents over HTTP in JSON, XML, CSV, or binary format.
Use the REST interface to query the index.

Verdict

Solr combines varied search modes with distributed operation, administration, and listed security capabilities. Note that older versions below 9.10 no longer receive updates, and future release timing is not announced in advance.

Questions

How much does Apache Solr cost?

The listed plan is free under Apache License, Version 2.0.

Is Apache Solr open source?

Yes. It is open source and licensed under Apache License, Version 2.0.

Which platforms does Solr support?

It is listed for Linux, macOS, Windows, API access, and self-hosted deployment.

How do applications send queries to Solr?

Solr has a REST query interface. It accepts documents over HTTP in JSON, XML, CSV, or binary formats and returns results in those formats.

Does Solr offer free support?

The Solr community provides free user support through its users mailing list and other listed channels.

Which Solr versions receive updates?

Versions older than 9.10 are end of life and will not receive further updates. Releases are not scheduled in advance.

Facts from Apache Solr's own pages

Administration: A responsive web administration interface and JMX metrics are supplied. · solr.apache.org, 15 Oct 2026
Community support: The Solr community provides free user support through its users mailing list and other listed channels. · solr.apache.org, 4 Oct 2026
Current release: Solr 10.0.0 is listed as the current stable major release, with 9.10.x receiving limited critical fixes. · solr.apache.org, 15 Oct 2026
Data formats: Documents can be indexed through HTTP as JSON, XML, CSV or binary, with results returned in those formats. · solr.apache.org, 15 Oct 2026
Deployment integrations: Official documentation covers Docker deployment and the project website links Kubernetes integration resources. · solr.apache.org, 15 Oct 2026
Discovery features: Solr supports faceting, autocomplete, spelling suggestions, hit highlighting, and search results clustering. · solr.apache.org, 4 Oct 2026
Discovery tools: Autocomplete, spell suggestions, result clustering and configurable hit highlighting are included. · solr.apache.org, 15 Oct 2026
Distributed scale: Solr provides distributed indexing, replication, load-balanced querying, automated failover, and recovery. · solr.apache.org, 4 Oct 2026
Documentation: The official reference guide covers concepts, deployment, configuration, indexing, querying and upgrades, and is written by Solr committers. · solr.apache.org, 15 Oct 2026
Downloads and support limits: Solr releases are not scheduled in advance; older versions below 9.10 are end of life and will not receive further updates. · solr.apache.org, 4 Oct 2026
Extensibility: Plugins can extend indexing, analysis, request handling and query parsing, and the source can be modified. · solr.apache.org, 15 Oct 2026
Faceting: Term, query, range, date and pivot faceting are built in for filtering and data exploration. · solr.apache.org, 15 Oct 2026
Founded: 2006 · solr.apache.org, 23 Sept 2026
Full-text search: It supports phrase, wildcard, join, grouping and other Lucene-powered matching methods. · solr.apache.org, 15 Oct 2026
Geospatial: Solr supports location filtering, polygons, latitude/longitude queries and Java Topology Suite integration. · solr.apache.org, 15 Oct 2026
Indexing and queries: Solr accepts documents as JSON, XML, CSV, or binary over HTTP and returns query results in those formats. · solr.apache.org, 4 Oct 2026
Intended users: The project describes Solr as suitable for global enterprises and weekend projects, and says it powers heavily trafficked websites and applications. · solr.apache.org, 4 Oct 2026
License: Solr is released under the permissive Apache License 2.0. · solr.apache.org, 15 Oct 2026
Limit: configuration and scaling: Gartner reviewers cite complex configuration, imperfect schema management, scaling difficulties and dependence on ZooKeeper. · gartner.com, 15 Oct 2026
Limit: documentation: G2 reviewers repeatedly request clearer documentation, more examples and better guidance for beginners. · g2.com, 15 Oct 2026
Limit: learning curve: Reviewers report that Solr is complex for newcomers and requires substantial technical skill during setup and operation. · gartner.com, 15 Oct 2026
Limit: real-time and UI gaps: G2 reviews mention weaker real-time architecture, slow feature evolution and no built-in JavaScript data-grid component. · g2.com, 15 Oct 2026
Maker funding model: Crunchbase describes the foundation as a US nonprofit funded by individual donations and corporate sponsors. · crunchbase.com, 15 Oct 2026
Maker headquarters and size: LinkedIn lists the Apache Software Foundation headquarters in Wilmington, Delaware, with 5,001–10,000 employees. · linkedin.com, 15 Oct 2026