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Fess vs Sosse: catalog facts
Fess	Sosse
Free Free and open source under Apache-2.0; commercial support is available.	Free Open source under the AGPL-3.0 license.
Windows, macOS, Linux, Web, Self-hosted	Web, Self-hosted, Command line
Crawler, indexer, admin console and search UI included Indexes Office, PDF and archive files from many sources	Searches crawled and archived pages Supports offline browsing of saved pages
Non-Docker installs need a separate OpenSearch setup Requires Java 21 and server resources	Requires self-hosting
Downloadable app, Self-hosted	Downloadable app, Web application, Self-hosted
Open source	Open source
License: Apache-2.0	License: AGPL-3.0
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 8, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.