1. HubSpot Sales
Email tracking, CRM for Gmail, and sales productivity tools in your inbox
Why it replaces SeeOnce Privacy: Covers similar ground in the Email category: Email tracking, CRM for Gmail, and sales productivity tools in your inbox
Best SeeOnce Privacy Alternatives in 2026
SeeOnce Privacy is a strong option, but it is not the right fit for everyone. Below are 10 alternatives compared on rating, install base, pricing and the use case each one actually wins on.
About SeeOnce Privacy
High strength end-to-end encryption with perfect forward secrecy for your favorite email, plus real-time secure chat
Free
Full reviewComparison at a glance
| Extension | Rating | Users | Pricing | Best for |
|---|---|---|---|---|
| SeeOnce Privacy (original) | — | — | Free | High strength end-to-end encryption with perfect forward secrecy for your favorite email, plus real-time secure chat |
| HubSpot Sales | — | — | Free | Email tracking, CRM for Gmail, and sales productivity tools in your inbox |
| SimpleLogin by Proton: Secure Email Aliases | — | — | Free | Easily create a different email for each website to hide your real email. Protect your inbox against spams, phishing, data breaches |
| SendSafely Encryption for Chrome and Gmail | 4.9 | 40K+ | Free | Chrome extension that provides end-to-end encryption for Gmail. Encrypt private emails and securely share files up to 10GB. |
| Quillbot: AI Writing Assistant with Humanizer, Paraphraser & AI Detector | 4.7 | 5M+ | Free | Write better emails, essays and messages with Quillbot's Grammar Checker, Paraphrasing Tool, Generative AI, Summarizer and more! |
| DeepL: translate and write with AI | 4.7 | 4M+ | Free | Translate while you read and write with DeepL Translate, the world’s most accurate translator. |
| Mailtrack | 4.4 | 3M+ | Freemium | Salespeople and recruiters who need to know when an email was actually opened. |
| Google Mail Checker | 4.1 | 2M+ | Free | Displays the number of unread messages in your Google Mail inbox. You can also click the button to open your inbox. |
| Apollo.io: Free B2B Phone Number & Email Finder | — | — | Free | Apollo enables users to find contact info, connect with buyers, track emails, and more for free. |
| Email Finder by ContactOut – Email Lookup Tool | 4.4 | 600K+ | Free | Find emails for 75% of Linkedin or ANY website. Save profiles to CRM. Chatgpt comments & email writer. Trusted by 76% of Fortune500. |
| Fathom AI Note Taker for Google Meet | 4.9 | 500K+ | Free | Records, transcribes & summarizes meetings FREE |
SeeOnce Privacy alternatives in detail
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2. SimpleLogin by Proton: Secure Email Aliases
Easily create a different email for each website to hide your real email. Protect your inbox against spams, phishing, data breaches
Why it replaces SeeOnce Privacy: Covers similar ground in the Email category: Easily create a different email for each website to hide your real email. Protect your inbox against spams, phishing, data breaches
3. SendSafely Encryption for Chrome and Gmail
Chrome extension that provides end-to-end encryption for Gmail. Encrypt private emails and securely share files up to 10GB.
Why it replaces SeeOnce Privacy: Covers similar ground in the Email category: Chrome extension that provides end-to-end encryption for Gmail. Encrypt private emails and securely share files up to 10GB.
4. Quillbot: AI Writing Assistant with Humanizer, Paraphraser & AI Detector
Write better emails, essays and messages with Quillbot's Grammar Checker, Paraphrasing Tool, Generative AI, Summarizer and more!
Why it replaces SeeOnce Privacy: Another popular Email extension: Write better emails, essays and messages with Quillbot's Grammar Checker, Paraphrasing Tool, Generative AI, Summarizer and more!
5. DeepL: translate and write with AI
Translate while you read and write with DeepL Translate, the world’s most accurate translator.
Why it replaces SeeOnce Privacy: Another popular Email extension: Translate while you read and write with DeepL Translate, the world’s most accurate translator.
6. Mailtrack
Read receipts and link tracking for Gmail.
Why it replaces SeeOnce Privacy: Another popular Email extension: Read receipts and link tracking for Gmail.
7. Google Mail Checker
Displays the number of unread messages in your Google Mail inbox. You can also click the button to open your inbox.
Why it replaces SeeOnce Privacy: Another popular Email extension: Displays the number of unread messages in your Google Mail inbox. You can also click the button to open your inbox.
8. Apollo.io: Free B2B Phone Number & Email Finder
Apollo enables users to find contact info, connect with buyers, track emails, and more for free.
Why it replaces SeeOnce Privacy: Another popular Email extension: Apollo enables users to find contact info, connect with buyers, track emails, and more for free.
9. Email Finder by ContactOut – Email Lookup Tool
Find emails for 75% of Linkedin or ANY website. Save profiles to CRM. Chatgpt comments & email writer. Trusted by 76% of Fortune500.
Why it replaces SeeOnce Privacy: Another popular Email extension: Find emails for 75% of Linkedin or ANY website. Save profiles to CRM. Chatgpt comments & email writer. Trusted by 76% of Fortune500.
10. Fathom AI Note Taker for Google Meet
Records, transcribes & summarizes meetings FREE
Why it replaces SeeOnce Privacy: Another popular Email extension: Records, transcribes & summarizes meetings FREE
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Direct comparisons with the extensions people weigh against it.
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Frequently asked questions
What is the best alternative to SeeOnce Privacy?
HubSpot Sales is the closest match. Covers similar ground in the Email category: Email tracking, CRM for Gmail, and sales productivity tools in your inbox
Is there a free alternative to SeeOnce Privacy?
Yes — HubSpot Sales, SimpleLogin by Proton: Secure Email Aliases, SendSafely Encryption for Chrome and Gmail are free.