Recoll is a desktop full-text search tool. Finds documents based on their contents as well as their file names. Can search most document formats, even if they're compressed (even Maildir/ and mailboxes). You may need external applications for text extraction. Based on Xapian. Primarily desktop but it could be run server-side. Indices are backwards-compatible.
Source code: https://framagit.org/medoc92/recoll
Flies on solid state storage!
Can be plugged into Searx: https://searx.github.io/searx/admin/engines/recoll.html
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