Inbox Zero vs Mailbutler Smart Assistant
Inbox Zero
inbox-zero.ai
Mailbutler Smart Assistant
mailbutler.ioSide by side
| Figure | Inbox Zero | Mailbutler Smart Assistant |
|---|---|---|
| Price from | $20/mo | $7/mo |
| Free plan | — | Yes |
| Free trial | Yes | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| Linux | — | Yes |
| iOS | Yes | Yes |
| Android | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | — |
| Plans published | 4 | 10 |
| Spec score · AI Email Assistants | 8.4 (#8) | 9.2 (#3) |
| Headquarters | Newark, Delaware, United States | Berlin, Germany |
| Security | The hosted product is SOC 2 compliant, and the Trust Center identifies SOC 2 Type 2 compliance. | Mailbutler says it is ISO/IEC 27001 certified and GDPR compliant, and that backend data is encrypted. |
| Support | Customers can contact support at [email protected]. | Mailbutler says its customer support team answers queries 24/7 and provides a Support Center. |
Plans
Inbox Zero
- Starter$20 a month
- Plus$35 a month
- Professional$50 a month
- EnterprisePriced on request
Mailbutler Smart Assistant
- StarterFree
- Professional$9 a month
- Smart$14 a month
- Business$32 a month
- Professional (yearly billing)$7 a month
- Professional (monthly billing)$9 a month
- Smart (yearly billing)$11 a month
- Smart (monthly billing)$14 a month
- Business (yearly billing)$24 a month
- Business (monthly billing)$32 a month
In their own words
Inbox Zero
Inbox Zero has no write-up on Specifiction yet; its figures are above.
Mailbutler Smart Assistant
Mailbutler Smart Assistant adds AI writing and email-management tools to Apple Mail, Microsoft Outlook, and Gmail. It drafts messages from keywords or prepares replies using details a user supplies, with controls for format, length, style, tone, and language. It can summarize selected emails, identify to-dos for Mailbutler Tasks, and suggest spelling and grammar improvements to drafts. Mailbutler says the assistant uses OpenAI GPT-4o. Smart Assistant is included in a 14-day trial, then requires a Smart or Business subscription. The separate free Starter plan includes a visible Mailbutler watermark on sent emails. Mailbutler says email subjects and bodies are processed by Microsoft Azure OpenAI Service in the EU, with personal data redacted before submission to the underlying model. It also says backend data is encrypted and that it is ISO/IEC 27001 certified and GDPR compliant. Apple Mail support is listed for macOS Tahoe, Sequoia, Sonoma, and Ventura; mobile apps require iOS 15 or later or Android 7 or later.