Overview

Fess is a self-hosted search server for organizations that need one search experience across websites, files and databases. It suits teams prepared to manage software on Java or Docker, especially when access controls and customizable integration matter. Its broad search and authentication toolkit is compelling at no license cost, but community support carries no guaranteed response.

Key features

Fess brings crawling, indexing, administration and the search interface into one system built on OpenSearch. Its crawler reaches web pages, file systems, Windows shared folders and databases, and can index Office documents and PDFs; external text extraction such as OCR can extend coverage. That range makes Fess useful for mixed repositories, though the self-hosted model means the organization must provide and operate the runtime.

Searchers can narrow results with facets and drill-down, while autocomplete, suggestions, cached results and thumbnails help users find and assess material. Secure search supports BASIC, DIGEST, NTLM and FORM authentication, as well as single sign-on through Active Directory, SAML and other methods. Permission synchronization is supported, an important distinction for organizations that cannot expose a shared index without respecting source access.

For integration, Fess can return JSON, connect to websites through JavaScript, and extend functionality with plugins. Its documentation covers an API, and access tokens can be used for external-system integration. These options make it adaptable, but organizations should expect to own the deployment and integration work.

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 response. It is the natural fit for organizations with the technical capacity to run and maintain a self-hosted search service.

Professional Support — custom pricing. Email support is priced per site. Silver includes 5 incidents/3 months and a first-response target of three business days; Gold includes 10 incidents/3 months with a two-business-day target; Platinum offers unlimited incidents and a one-business-day target. Organizations that need a defined support path can choose a tier, while teams comfortable relying on the community can avoid support fees.

Platforms

Fess is self-hosted and runs on operating systems with a Java or Docker runtime. Its listed platforms include Linux, macOS, Windows, web and API; it is not a hosted search service.

Who it's for

Fess is best suited to organizations that need to search across varied internal and public content, require authentication and permission-aware access, and can handle self-hosting. It is less suitable for teams that need guaranteed help without purchasing professional support or that want a managed service rather than operating their own deployment.

Pros and cons

Pro: Broad crawler coverage, including databases, Windows shares and common office documents, helps consolidate search across unlike repositories.
Pro: Multiple authentication methods, single sign-on and permission synchronization support secure search rather than merely indexing content.
Pro: Apache licensing allows free personal and commercial use, while JSON, JavaScript integration, plugins and API support offer routes to extend it.
Con: Self-hosting on Java or Docker places runtime and deployment responsibility on the organization.
Con: The open-source edition has no guaranteed support; response targets require paid, per-site professional support.

Alternatives

For a broader category comparison, see AI Enterprise Search Software.

SWIRL AI Search is worth considering if you want a free tier and trial alongside paid evaluation and departmental options.
PipesHub is another free, self-hosted option, with a community edition that includes Docker deployment, core indexing and search, BYO LLMs and embeddings, and a no-code agent builder.
Dropbox Dash may fit teams seeking a paid, cross-platform product with a free trial and plans sized by user count rather than a self-hosted server.
Onyx is an alternative if you want a freemium web product with a business plan that includes chat and search, major LLM access and custom AI agents.
SearchBlox SearchAI is a paid alternative with a stated annual plan covering up to 10,000 documents or URLs and 100,000 searches per month.
Viglet Turing ES is another free search option for web, Windows and Linux.
Elastic Search AI is another freemium web option.
Amazon Kendra is a paid alternative with a free trial and API and web platforms.

Verdict

Choose Fess if you need flexible, permission-aware enterprise search and have the capacity to run a Java- or Docker-based service. Its breadth of content sources, authentication and integration options is the strongest reason to choose it; the main reason to look elsewhere is the operational burden or the need for guaranteed support without a paid plan.

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

Fess vs Sinequa

Fess

Sinequa