Search inside every document on your computer. By content. By context. Not just filenames.
LocalSynapse is a desktop app
It runs on Windows and macOS. Open localsynapse.com on your computer to download.
v2.17.0 · Free forever · No login required · Apache 2.0
Features
Everything Search finds filenames. LocalSynapse finds the answer inside your files.
Word, Excel, PowerPoint, PDF, HWP, EML, MSG, and more. Search by what's inside, not the filename.
Every search, every embedding, every byte stays on your machine. No network. No upload. Works in air-gapped environments.
Privacy firstPhrase search, word-boundary boost, click learning. Files you open often rank higher next time. Drafts and revisions auto-grouped.
Four indexing modes from Stealth (invisible background) to Mad Max (full hardware). Switch any time. Your PC stays responsive, your way.
GPU execution paths for embedding — DirectML, CoreML, CUDA — are in development. They are not enabled in the current release: indexing runs on your CPU today.
In developmentA global hotkey opens search from anywhere. Lives in your tray. Two seconds, no window switching, back to work.
Double-click for search UI. Run for MCP server. Same binary, two modes.LocalSynapse mcp
Comparison
Everything finds filenames fast. Windows Search is built in. LocalSynapse reads what's inside.
| Capability | Windows Search | Everything | LocalSynapse |
|---|---|---|---|
| Filename search | Yes (fastest) | ||
| Search inside file contents | Partial | — | Yes (13+ formats) |
| Word, Excel, PowerPoint | Partial | — | |
| PDF, HWP | — | — | |
| AI semantic search | — | — | |
| 100% offline | |||
| MCP server for AI agents | — | — | |
| Price | Free | Free | Free |
Filename search
Search inside file contents
Word, Excel, PowerPoint
PDF, HWP
AI semantic search
100% offline
MCP server for AI agents
Price
Everything finds filenames. LocalSynapse finds answers. Read the full comparison →
Roadmap
Your files didn't appear out of nowhere. We're building the full picture.
Recently shipped
Choose how indexing uses your machine, from Stealth (invisible background) to Mad Max (full hardware).
Apple Silicon and Intel builds. Ad-hoc signed for safe first launch.
Global hotkey, tray icon, auto-start with your system. Find a file in two seconds without breaking your flow.
Every outbound connection is disclosed in plain English. The free tier sends zero data, and we prove it.
Embedding pipeline rewritten for 2–3× throughput. Performance Mode that adjusts itself to what you're doing.
In development
See how your work unfolded. Email threads, attachments, and file edits in one time-ordered view. 100% offline by default, like always.
DirectML (Windows), CoreML (Apple Silicon), and CUDA execution paths for embedding. Not enabled in the current release — indexing runs on CPU today.
Updates
Continuously improving.
LocalSynapse 2.17.0
LocalSynapse 2.16.1
LocalSynapse 2.16.0
LocalSynapse 2.15.3
LocalSynapse 2.15.2
Your feedback directly shapes what we build next.
Free, offline, no account needed. Just install and search.
Apache 2.0 · Open source on GitHub