Overview

Fess is an open-source search server that brings websites, files and database content into a self-hosted search experience. It is best suited to teams that can operate Java or Docker software and need control over indexing and access. The trade-off is a capable free system without guaranteed community support.

Key features

Fess combines crawling, indexing, administration and a search interface on OpenSearch. Its crawler covers web pages, file systems, Windows shared folders and databases, and handles formats such as Office documents and PDFs; external extraction tools such as OCR can extend coverage. That breadth suits mixed repositories, but teams remain responsible for the runtime and deployment.

Facets and drill-down help users narrow results, while autocomplete, suggestions, cached results and thumbnails make the search interface more useful beyond a simple query box. Authentication includes BASIC, DIGEST, NTLM and FORM, plus single sign-on through Active Directory, SAML and other methods. Permission synchronization is supported, which matters when search must respect access boundaries rather than expose a common index indiscriminately.

For integration, Fess can return JSON, connect to websites with JavaScript and accept plugins for extensions. Its API documentation and access tokens support connections to external systems. These options make it adaptable to an existing stack, although they still call for implementation and operational ownership.

Pricing

Fess Open Source: 0.00 USD per free. The Apache-licensed edition is free for personal and commercial use, with community support and no guaranteed support. It is the natural fit for teams able to maintain the deployment themselves.

Professional Support: custom pricing. Support is per site by email: Silver includes 5 incidents/3 months, Gold 10 incidents/3 months and Platinum unlimited incidents. First-response targets are three business days for Silver, two for Gold and one for Platinum. This is the route for organizations that need a defined support channel and response target; the free edition does not include that assurance.

Platforms

Fess is self-hosted and runs on operating systems with a Java or Docker runtime. It is listed for Linux, macOS and Windows, as well as web and API use. The latest stable release is Fess 15.8.0, with Java 21 and OpenSearch 3.8.0.

Who it's for

Fess fits organizations that need to search across varied internal and web sources, require permission-aware access, and want to operate the search service within their own environment. It is less suitable for teams seeking a managed service or guaranteed support without arranging professional support.

Pros and cons

Pros: Broad crawling across web, file and database sources makes it useful for heterogeneous repositories.
Pros: Multiple authentication methods, single sign-on and permission synchronization support controlled search access.
Pros: Apache licensing permits personal and commercial use without a software license fee.
Cons: Java or Docker runtime requirements and self-hosting put deployment and ongoing operation on the adopting team.
Cons: Community support has no guaranteed response; professional support has custom pricing and incident-based tiers.

Alternatives

For a directory of related options, browse AI Enterprise Search Software.

Choose PipesHub if a self-hosted, open-source option with Docker deployment, core indexing and search, BYO LLMs and embeddings, and a no-code agent builder better matches the stack.

OpenSearch is a fit when the priority is the underlying open-source search engine itself, with no licensing fees, rather than Fess's bundled crawler, administration console and search interface.

Consider SWIRL AI Search if a paid evaluation pilot is preferable to adopting a free self-hosted server outright.

Amazon Kendra is an alternative for teams considering a paid search service with a free trial, rather than a self-hosted system.

Choose SearchBlox SearchAI if its paid annual plan and stated document and monthly search allowances suit the expected workload.

Dropbox Dash is worth considering for teams seeking a paid product with plans sized by user count rather than a self-managed search server.

InSearch may suit teams that want a paid web product with cited answers and permission-aware access.

Onyx is another option for teams considering a freemium product with paid business capabilities.

Verdict

Choose Fess if your team needs broad, permission-aware search across mixed sources and is prepared to run a self-hosted service. Its strongest case is the combination of source coverage and search controls under a free Apache license. Look elsewhere if managed deployment or guaranteed support is central to the decision.

	Fess	Glean Agent Builder
Free plan	Yes	No
Free trial	No	No
Paid from	Free	—
Open source	No	No
Platforms	api, Linux, macOS, self-hosted, Web, Windows	Web
Free plan	Yes	—
Permission sync	Yes	—
Answer citations	Yes	—
Deployment options	self-hosted	—
Admin controls	Yes	—

Fess vs Glean Agent Builder

Fess

Glean Agent Builder