A typical problem for a webmaster with a fleet of domains: every new site (for example, an aggregator or a catalog) needs an email for contact (info@) and a reliable SMTP for sending technical emails (registration, notifications). Multiplying paid boxes on Zoho or Google Workspace for each micro-project is expensive, and setting up your own mail server carries the risk of ending up in spam and puts unnecessary load on the VPS (OOM risk).
Below is a proven architecture that allows you to manage mail on dozens of domains using one “master mailbox” and cloud services.
1. Inbound: Single Window Principle
Instead of creating and paying for real mailboxes for each new domain or satellite, forwarding (Email Routing) is used. This allows you to consolidate all message flows and not waste time checking dozens of different control panels.
Today, almost every modern domain registrar offers free email forwarding — this feature has become an industry standard and is available immediately after purchasing a domain. If your project is already under Cloudflare protection, their Email Routing service will be the fastest solution for “one-click” setup.
- How it works: You create a virtual alias, for example — [email protected], which transparently redirects all incoming emails to your main “master mailbox” (for example, a secure account in Zoho or Proton).
- Pros: Completely free, does not require setting up complex MX records for storing mail on the server, and does not consume your VPS’s RAM. Sets up in 2 minutes.
2. Master Mailbox: Where to Store and Read Email
To receive all redirected emails, it is better to use services with a high level of security:
Zoho Mail (Free Tier): An excellent solution if you already have one domain set up. Stable, has a good mobile app. Limitation — the free plan allows you to work with only one confirmed domain for outgoing mail.
Proton Mail: The choice for those who put privacy first. You can use a free account as the destination point for all forwardings from Cloudflare.
3. Outbound: Transactional SMTP
Site engines (PHP/JS) require an SMTP connection to send system emails. To ensure that emails are guaranteed to reach users, use specialized services with free limits:
| Service | Limit (free) | Features |
|---|---|---|
| MailerSend | up to 500 emails/month | Very simple integration, excellent API, fast SMTP. |
| Resend | up to 3000 emails/month | Minimalist design, popular with JS developers, limit 100 emails/day. |
| Brevo | 300 emails/day | The most stable giant, good deliverability in RU and CIS. |
MailerSend
One of the most balanced services from the creators of MailerLite. Focused specifically on transactional mail (via API or SMTP).
- Limits: The free plan includes up to 500 emails per month. Then — flexible rates (from $5.60 for 5000 emails).
- Pros: Ideal documentation, very simple domain verification process, and high sending speed. There is a powerful template builder if you need to send beautiful registration emails.
- For whom: The best choice for “medium” sized projects where 100 emails a day (Resend limit) might be not enough.
Resend
The most “trendy” and modern service among developers. Focused on maximum API purity and integration with the React stack (React Email).
- Limits: Free tier gives 3000 emails per month with a limit of 100 emails per day.
- Pros: Incredibly clean interface, instant setup, and very detailed real-time logs. If the project is on JS/PHP and does not send mass mailings, this is the fastest way to working email.
- Features: On the free plan, logs are stored for only 1 day — this is enough for debugging registration, but not enough for long-term monitoring.
Brevo (formerly Sendinblue)
A French giant that historically works well with European and CIS providers (mail.ru, gmail).
- Limits: 300 emails per day (about 9000 per month) on the free plan without a total term limit.
- Pros: No limit on the total number of emails per month — only a daily limit. Very reliable infrastructure and built-in CRM.
- For whom: Ideal for large catalogs and forums with high user activity during the day.
Proton Mail (Business SMTP)
Although Proton Mail is known as secure mail, in business plans they have an SMTP Relay feature.
- Features: This is not a classic “mailer” like MailerSend. It is a tool for sending emails through Proton’s encrypted servers using your domain.
- Pros: Maximum privacy and server reputation. Emails sent via Proton have the highest credit of trust from other mail services.
- For whom: If the project is related to privacy (VPN, Proxy) and you need correspondence with tech support or notifications not to be analyzed by Google’s advertising algorithms.
Amazon SES (Simple Email Service)
The “professional’s” choice when the email count goes into the hundreds of thousands.
- Price: The cheapest on the market — $0.10 per 1000 emails. The free tier (3000 emails/month) is valid only for the first 12 months.
- Pros: Infinite scalability and minimum price.
- Cons: Most complex setup (need to confirm “Identity”, request “Sandbox” exit). AWS support can be slow.
- For whom: When a project “takes off” and the free limits of MailerSend/Brevo become tight.
Postmark
A service with a fanatical attitude towards deliverability. They separate transactional and marketing email flows onto different servers.
- Limits: Free trial period — 100 emails per month forever (for tests only). Paid plans start at $15 for 10,000 emails.
- Pros: The highest speed of reaching the “Inbox” among all competitors. Most detailed analytics for each email (opens, clicks, bounces).
- For whom: For critical notifications (e.g., password recovery or payment) where delay or landing in spam is unacceptable.
4. Technical Setup (DNS)
In the case of a MailerSend and Cloudflare combo, MailerSend will offer to authorize in Cloudflare and automatically configure the necessary DNS records — very convenient.
To prevent mail from falling into spam, for each domain (even if it’s a copy or alternative site), it is necessary to register three records in Cloudflare:
1. SPF (Sender Policy Framework) Allows the selected service (e.g., MailerSend) to send mail.
TXT @ v=spf1 include:_spf.mailersend.net ~all2. DKIM (DomainKeys Identified Mail) Digital signature of the email. The value (public key) is provided by the service itself (MailerSend/Resend) after adding the domain.
3. DMARC Instruction for mail servers on what to do with suspicious emails. To start, a soft policy is suitable:
TXT _dmarc v=DMARC1; p=none;Strategy Summary
Inbound: All fly to one protected mailbox (Zoho/Proton) via Cloudflare Routing.
Outbound: Configured via the SMTP of an external service (MailerSend/Resend).
Result: Zero load on your VPS, no costs for mail licenses, and high deliverability of emails to users worldwide.
