Spike
8.5#4 in email clientsFrom $4 a monthFree planAndroidiOSWebmacOS
VisitSpike vs Synapse
What both publish
| Fact | Spike | Synapse |
|---|---|---|
| App coverage | all | desktop |
| Calendar tools | Yes | Yes |
| Free plan | Yes | No |
| Integrations | Spike supports Google Drive, Dropbox, and OneDrive for cloud attachments, and its calendar feature names Google Calendar, Outlook, and Apple Calendar. | Listed plugins include Asana, ClickUp, Google Calendar, and Reminders; the site also describes adding integrations in Rust. |
| Privacy | Spike says it is ad-free and does not rent, sell, distribute, or monetize user data, while non-personal data may be used to improve its service. | The site lists zero telemetry events, analytics scripts, cloud relays, and stored passwords. |
| Product | Spike describes itself as an AI-powered inbox that brings email, calls, notes, tasks, and to-dos into one hub and turns email threads into chat-like conversations. | Synapse is a Windows email client with on-device AI. |
| Security | Spike says message data is encrypted with AES-256 using a per-message private key and that it has periodic external security audits. | The site says credentials are encrypted with AES-256 and the key is sealed inside the device's hardware TPM. |
| Support | The pricing page lists standard support for Starter, priority support for Team and Pro, and VIP support for Business and Ultimate. | The site lists [email protected] as its contact email. |
| Unified inbox | Yes | Yes |
Spike plans
- StarterFree
- Team$4 a month
- Business$8 a month
- FreeFree
- Pro$6 a month
- Ultimate$12 a month
Synapse plans
- Synapse€4.99, paid once
Pick Spike if…
Spike may suit people or teams looking to bring email, scheduled messages, and calendar tools together across desktop and mobile platforms. Its plans cover different email, storage, team, and file-upload needs.
Pick Synapse if…
You want what its maker publishes above — check its page for the details.