LocalSynapse review
Free, open-source local search with semantic matching and support for 13+ file formats.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
LocalSynapse is a free, open-source desktop search application for Windows and macOS. It is aimed at people who want to find information inside local documents rather than search only filenames, with particular appeal for solo users and small teams prioritizing private semantic search. The vendor says indexing and search run on the local machine, with no file uploads. Search covers more than 13 formats, including Word, Excel, PowerPoint, PDF, HWP, EML and MSG.
Its search combines semantic matching with phrase search and word-boundary ranking. Ranking learns from files a user opens, while grouping drafts and revisions can help distinguish related versions. Four indexing performance modes provide a choice of indexing behavior. For quick access, the application offers a global hotkey, tray icon and system auto-start. An MCP server mode also lets AI agents search local files, extending its use beyond a standalone search interface. These features make it a broader local search tool than a filename finder, though the supported index locations are not specified.
The vendor describes the product as free and open source under Apache 2.0, making it suitable for buyers who want desktop search without a paid plan. GPU acceleration is described as in development, not enabled in the current release. Choose LocalSynapse if Windows or Mac support, local indexing, and semantic and phrase search across documents are the priorities. It is less suitable for people who need a different platform or need assurance about specific index locations before adopting a tool. Email support is listed as a support channel.
LocalSynapse pros and cons
- Where it wins
- Searches contents across 13+ formats, including Word, PDF, EML and MSG
- Indexes and searches files locally, with no uploads, according to the vendor
- Combines semantic and phrase search with ranking informed by opened files
- Where it doesn't
- Limited to Windows and macOS desktop use
- Supported index locations are not specified
- GPU acceleration is still in development
LocalSynapse fact sheet, pricing and score →
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