One moves you to an encrypted mailbox. The other keeps you in Gmail.
The real choice is privacy-by-default vs staying in the inbox you already use.
Proton Mail is an encrypted mailbox you migrate to: to use a custom domain you need a paid Proton plan (roughly $48-$120/yr), and you give up Gmail's interface, search, and integrations because mail now lives inside Proton's own app. SendMailAs takes the opposite path - it keeps you in your existing free Gmail and simply adds custom-domain send and receive for $29/yr flat, with unlimited domains and automatic DNS configured through Cloudflare. The honest tradeoff is this: Proton gives you end-to-end encryption, zero-access storage, and privacy-by-default under Swiss law, which SendMailAs does not provide. SendMailAs instead prioritizes staying in the Gmail inbox you already use and a low flat price, not end-to-end encryption. So if encrypted, private email matters most, choose Proton; if keeping Gmail and minimal cost matter most, choose SendMailAs.
Proton Mail is its own encrypted mailbox with its own web and mobile apps. Using it means leaving Gmail's interface, search, labels, and integrations behind. SendMailAs keeps your existing free Gmail as your inbox and just adds custom-domain addresses to it - nothing to migrate, no second app to check.
Proton does not support custom domains on its free plan - you need a paid plan, roughly $48-$120/yr depending on tier and billing. That price bundles a broader privacy suite. SendMailAs is $29/yr flat for unlimited domains, with the first domain free forever. If you only want custom-domain email, the cost gap is significant.
With Proton you manually add MX, SPF, DKIM, and DMARC records at your registrar for every domain and verify them in Proton's settings. SendMailAs pre-generates the exact records and you paste them into your existing DNS host once - no nameserver change, and the dashboard verifies them automatically with no per-domain guesswork.
This is Proton's real advantage and an honest tradeoff. Proton provides end-to-end encryption between Proton users, zero-access encrypted storage so Proton itself cannot read your stored mail, and is based in Switzerland under strong privacy law. SendMailAs does not offer end-to-end encryption - it relays mail through your Gmail account using standard transport encryption. If privacy-by-default is your priority, Proton Mail is the better choice.
| Feature | SendMailAs$29/yr | Proton Mail |
|---|---|---|
| Custom domain email | Yes - Custom domain email | Yes - Custom domain email |
| Works inside existing Gmail | Yes - Works inside existing Gmail | - |
| Free custom domain | 1 domain free | - |
| End-to-end encryption | - | Yes - End-to-end encryption |
| Zero-access encrypted storage | - | Yes - Zero-access encrypted storage |
| Privacy-focused jurisdiction | - | Switzerland |
| Keep Gmail search & filters | Yes - Keep Gmail search & filters | - |
| DNS setup | Automatic | Manual (MX, SPF, DKIM, DMARC) |
| Domains (paid) | Unlimited | Limited by tier |
| Send + receive on custom domain | Yes - Send + receive on custom domain | Paid plan |
| Separate mailbox to manage | No (stays in Gmail) | Yes (Proton app) |
| Yearly price | $29/yr flat | ~$48-$120/yr |
| Setup time | 5 minutes | Migration + DNS |
Proton bundles a privacy suite into paid tiers. SendMailAs charges once.
| Scenario | SendMailAs | Proton Mail |
|---|---|---|
| Custom domain, 1 domainProton needs a paid plan for any custom domain | Free | ~$48/yr |
| Send + receive, 1 domainFirst SendMailAs domain free forever | Free | ~$48/yr |
| Send + receive, 5 domainsMore domains needs Proton Unlimited/Business | $29/yr | ~$120/yr |
| Send + receive, 10+ domainsSendMailAs Pro has no domain cap | $29/yr | ~$120/yr+ |
| Privacy: end-to-end encryptionProton's core advantage - SendMailAs is not E2E encrypted | Not offered | Included |
Proton pricing is approximate (~$48-$120/yr depending on tier and billing cycle) and bundles a broader privacy suite. SendMailAs Pro: $29/yr flat. Prices as of May 2026 - check Proton's site for exact current numbers.
Proton Mail is a genuinely strong privacy product. End-to-end encryption, zero-access storage, and a Swiss jurisdiction are real advantages, and SendMailAs does not match them. If private, encrypted email is what you are optimizing for, Proton is the right tool and worth the move.
But if you just want you@yourdomain.com working in the Gmail you already use - sending and receiving, with automatic DNS, without migrating to a new mailbox - SendMailAs does that for $29/yr with unlimited domains. Proton requires a paid plan (~$48-$120/yr) and moving your email life into Proton's app.
For privacy-by-default, choose Proton. For staying in Gmail at a low flat price, choose SendMailAs. They optimize for different things.
No. Proton Mail's free plan does not support custom domains. To use you@yourdomain.com with Proton you need a paid plan - Proton Mail Plus or Proton Unlimited - which runs roughly $48-$120/yr depending on tier and billing cycle. SendMailAs adds custom-domain send and receive to your existing free Gmail, with the first domain free forever and $29/yr flat for unlimited domains.
Effectively yes. Proton Mail is its own encrypted mailbox with its own web app and mobile apps. To get Proton's end-to-end encryption you read and send mail inside Proton, not Gmail. You lose Gmail's search, filters, labels, and integrations. SendMailAs is the opposite approach - it keeps you in the Gmail inbox you already use and just adds custom-domain addresses.
Yes, and this is the honest tradeoff. Proton provides end-to-end encryption between Proton users, zero-access encrypted storage, and is based in Switzerland under strong privacy law. SendMailAs does not provide end-to-end encryption - it relays mail through your Gmail account, which uses standard transport encryption. If E2E encryption and privacy-by-default are your priority, Proton is the better fit.
Different products. Proton is a full encrypted mailbox provider with apps, calendar, VPN, and drive bundled into its paid tiers, so custom-domain support comes with a broader privacy suite at ~$48-$120/yr. SendMailAs does one thing - custom-domain email inside your existing Gmail - for $29/yr flat with unlimited domains. You are not paying for a new mailbox or a privacy bundle.
Not really. Proton can import old mail and forward, but the Proton experience expects you to use the Proton mailbox going forward. With SendMailAs your primary inbox stays your normal free Gmail account - custom-domain mail simply arrives there and you send from it using Gmail's 'Send mail as'.
Yes. With Proton you research and add MX, SPF, DKIM, and DMARC records at your registrar for each domain and verify them in Proton's settings. SendMailAs pre-generates the exact MX, SPF, DKIM, and DMARC records for you to copy-paste at your existing DNS host and then verifies them automatically - no figuring out the records per domain by hand.
Proton's lower paid tier typically supports a small number of domains, with more on Proton Unlimited or Business. SendMailAs Pro is $29/yr for unlimited domains and unlimited addresses with no per-domain charge. Proton pricing and limits are approximate and as of May 2026 - check Proton's site for exact current numbers.
Choose Proton Mail if end-to-end encryption, zero-access storage, and a privacy-focused jurisdiction matter most and you are willing to move out of Gmail and pay for it. Choose SendMailAs if you want to stay in your existing free Gmail, get custom-domain send and receive with pre-generated records you paste at your existing DNS host and auto-verification, and pay $29/yr flat for unlimited domains - accepting that it is not end-to-end encrypted.
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