Synapse
by Synapse
What Synapse is
Synapse is a Windows 11 desktop email client from Synapse in Turin, Italy. It provides a unified inbox, offline access and calendar tools, with on-device AI available as an option. Gmail accounts use the Gmail REST API, while other providers connect through IMAP IDLE push. Search combines BM25 full-text indexing with 768-dimensional multilingual semantic embeddings and supports more than 100 languages. The optional Qwen3.5-4B model can run on a Vulkan GPU, or you can provide a cloud API key. Plugins listed include Asana, ClickUp, Google Calendar and Reminders. Google and Microsoft sign-in uses OAuth2 with PKCE, and the maker says passwords are not stored. Credentials use AES-256 encryption with the key sealed in the device TPM. Mail is cached locally in SQLite, and inference is offline after the model download. Pricing starts at €4.99, with no free plan.
Who it suits
Synapse suits Windows users who want email, calendars and offline AI features in one desktop client. It also fits people needing multilingual search and locally cached mail.
What it does well
- Unified inbox, offline access and calendar tools
- Search supports more than 100 languages
- Optional local Qwen3.5-4B AI model
- AES-256 credential encryption with hardware TPM key
- Listed plugins include Asana and Google Calendar
What to know first
- Windows 11 x86_64 is the only listed platform
- No free plan
- Requires 16 GB RAM and storage
- Optional AI model needs about 2.5 GB
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Synapse | One-time purchase · No subscription · Lifetime access · All future updates included · No tiers | €4.99, paid once |
As synapsemail.app lists them, read 11 Oct 2026. The maker's own page has the final word.
Verdict
Synapse combines a unified Windows inbox with calendar tools, multilingual semantic search and optional local AI. Its one-time €4.99 purchase includes lifetime access and future updates, while platform support remains limited to Windows 11 x86_64.
Facts from Synapse's own pages
- App coverage
- desktop · synapsemail.app, 20 Sept 2026
- Availability
- The site says Synapse is in active development and invites visitors to join a launch-notification list. · synapsemail.app, 11 Oct 2026
- Calendar tools
- Yes · synapsemail.app, 20 Sept 2026
- Email accounts
- Synapse supports OAuth2 for Google and Microsoft via PKCE and says it does not store passwords. · synapsemail.app, 11 Oct 2026
- Email sync
- It uses the Gmail REST API for Gmail and IMAP IDLE push for other providers. · synapsemail.app, 11 Oct 2026
- Free plan
- No · synapsemail.app, 20 Sept 2026
- Headquarters
- Turin, Italy · synapsemail.app, 28 Sept 2026
- Integrations
- Listed plugins include Asana, ClickUp, Google Calendar, and Reminders; the site also describes adding integrations in Rust. · synapsemail.app, 11 Oct 2026
- Local AI
- Its optional Qwen3.5-4B model runs on a Vulkan GPU, or users can provide their own cloud API key. · synapsemail.app, 11 Oct 2026
- Local data
- Mail is cached in a local SQLite database, and the site says AI inference is offline after the model's one-time download. · synapsemail.app, 11 Oct 2026
- Maker
- The site identifies Valerio as the builder of Synapse. · synapsemail.app, 11 Oct 2026
- Notable limit
- Windows 11 x86_64 is listed as the only supported platform. · synapsemail.app, 11 Oct 2026
- Offline access
- Yes · synapsemail.app, 20 Sept 2026
- Privacy
- The site lists zero telemetry events, analytics scripts, cloud relays, and stored passwords. · synapsemail.app, 11 Oct 2026
- Product
- Synapse is a Windows email client with on-device AI. · synapsemail.app, 11 Oct 2026
- Requirements
- The stated requirements include Windows 11 x86_64, 16 GB RAM, and 1 GB storage, plus about 2.5 GB for the optional AI model. · synapsemail.app, 11 Oct 2026
- Search
- It combines BM25 full-text search and 768-dimensional multilingual semantic embeddings, with support for 100+ languages. · synapsemail.app, 11 Oct 2026
- Security
- The site says credentials are encrypted with AES-256 and the key is sealed inside the device's hardware TPM. · synapsemail.app, 11 Oct 2026
- Support
- The site lists [email protected] as its contact email. · synapsemail.app, 11 Oct 2026
- Unified inbox
- Yes · synapsemail.app, 20 Sept 2026
Where Synapse stands on Freedom251
- Email clients#131 of 142