What is Fess used for?

Fess is a self-hosted enterprise and site search server built on OpenSearch, with crawlers, an admin UI, a REST API and AI-assisted search. It is a good fit for building intranet search across files and wikis, adding site search to a public website, and searching documents with permission-aware results.

Yes. Fess is open source under the Apache-2.0 licence. Its source code is on GitHub at codelibs/fess and is written mainly in Java.

Yes. Fess is open source, so the software itself is free to use.

Can I self-host Fess?

Yes. Fess can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is Fess an alternative to?

Fess is an open-source alternative to Coveo, Amazon Kendra, Mindbreeze and Lucidworks. Other open-source alternatives to Coveo include Open Semantic Search, OpenSearchServer and Swirl.

Is Fess actively maintained?

Yes. The most recent commit to Fess was on 2 October 2026. The project has 1.1k stars on GitHub.

Fess: open-source alternative to Coveo, Amazon Kendra

About Fess

Fess is an open-source enterprise search server that you install and run on any platform with a Java runtime. It is built on OpenSearch but does not require prior OpenSearch knowledge, because everything is configured in a browser-based administration interface. It can also serve as a free site search for your own website.

A built-in crawler collects documents from web sites, file systems and data stores such as databases, CSV files, cloud storage and SaaS sources, and handles many formats including Microsoft Office files, PDF and archives. Search supports faceting, sorting and suggestions, results can be filtered by role and permission, and single sign-on works with LDAP, OpenID Connect, SAML, SPNEGO and Microsoft Entra ID. It offers a REST API, text analysis for over 20 languages, plugins, and AI features for RAG and semantic search.

Fess is written in Java and licensed under Apache-2.0. It needs Java 21 or newer for the ZIP, RPM and DEB packages, and Docker images bundle OpenSearch. It suits organizations that want a private, self-managed alternative to Elasticsearch-based setups or Google Site Search.

Key features

Crawlers for web, files, and databases
Browser-based administration UI
Full-text search with facets and suggestions
Role-based filtering of results
SSO with LDAP, OIDC, SAML, and Entra ID
AI, RAG, and semantic search support

Good fit for

→Building intranet search across files and wikis
→Adding site search to a public website
→Searching documents with permission-aware results

Built with: Java; Docker
Tags: enterprise-search; opensearch; crawler; full-text-search; java; rag; site-search; self-hosted; semantic-search

Fess: questions and answers

What is Fess used for?: Fess is a self-hosted enterprise and site search server built on OpenSearch, with crawlers, an admin UI, a REST API and AI-assisted search. It is a good fit for building intranet search across files and wikis, adding site search to a public website, and searching documents with permission-aware results.
Is Fess open source?: Yes. Fess is open source under the Apache-2.0 licence. Its source code is on GitHub at codelibs/fess and is written mainly in Java.
Is Fess free?: Yes. Fess is open source, so the software itself is free to use.
Can I self-host Fess?: Yes. Fess can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is Fess an alternative to?: Fess is an open-source alternative to Coveo, Amazon Kendra, Mindbreeze and Lucidworks. Other open-source alternatives to Coveo include Open Semantic Search, OpenSearchServer and Swirl.
Is Fess actively maintained?: Yes. The most recent commit to Fess was on 2 October 2026. The project has 1.1k stars on GitHub.