What Are BIMI and MTA-STS? The Future of Email Security Standards

Email communication is protected by an ever-evolving stack of security layers. The trio of SPF, DKIM, and DMARC — the foundation of antispam protection — has now become almost a standard. But the cybersecurity world doesn’t stand still; new protocols like BIMI and MTA-STS are stepping in to both raise security and elevate corporate prestige.

So what exactly are BIMI and MTA-STS, and what advantages do they offer your organization?

What Is BIMI (Brand Indicators for Message Identification)?

BIMI is, in short, a standard that lets your emails appear in the recipient’s inbox with your own brand logo. While email clients (Gmail, Yahoo, Apple Mail, etc.) normally show the first letter of the company name in place of a brand logo, BIMI-compliant emails light up with your trademarked brand logo.

Why Should You Use BIMI?

1. Visual Reputation and Brand Recognition: It makes you stand out in the inbox. Logos do more than build trust; they also help your brand stick in memory.
2. Trust and Phishing Protection: When users see the logo of a brand they recognize, they understand the email isn’t a forgery.
3. It Encourages DMARC: A non-negotiable prerequisite for using BIMI is that your email infrastructure has a DMARC policy at p=quarantine or p=reject. In other words, BIMI rewards companies (with logo display) for taking their email security to the highest level.

How Is BIMI Set Up?

BIMI setup involves a number of technical and procedural steps:

• A DMARC policy configured in strict mode.
• Your logo hosted in .SVG format (TinyPS profile) on a secure HTTPS server.
• A VMC (Verified Mark Certificate) — some providers like Gmail require this certificate to prove the logo is legally trademarked.
• Adding the BIMI TXT record to your DNS records.

You can use our BIMI Lookup tool to check the status and validity of your BIMI record.

What Is MTA-STS (Mail Transfer Agent Strict Transport Security)?

MTA-STS is a security mechanism that enforces connection encryption (TLS) between mail servers and prevents emails from being intercepted in transit (Man-in-the-Middle attacks).

Why Do You Need MTA-STS?

Email has been sent in “plaintext” since the very beginnings of the internet. Today, mail servers attempt to encrypt the connection using the STARTTLS protocol (Opportunistic TLS). But an attacker can step in during the connection, block the STARTTLS signal (a downgrade attack), and force the communication back to an unencrypted format.

MTA-STS comes in at exactly this point. It tells other servers: “You can only connect to my mail servers with a valid certificate over a secure TLS connection. If you cannot establish an encrypted connection, do not deliver the email at all!”

Advantages of MTA-STS

• Enterprise Communication Security: Confidential company data is prevented from being read in transit.
• Prevention of Manipulation: Makes it impossible to alter emails along the way.
• Compliance with International Standards: Especially helpful for finance and healthcare organizations in meeting regulations such as the Turkish Personal Data Protection Law (KVKK), GDPR, and similar frameworks.

MTA-STS Setup Process

1. Host a policy file (.well-known/mta-sts.txt) accessible over HTTPS on a subdomain (e.g., mta-sts.yourcompany.com).
2. Add the dedicated MTA-STS TXT record to your DNS.
3. Configure TLS Reporting (TLS-RPT) to monitor encryption failures.

To analyze your policy and create a valid configuration, take a look at our MTA-STS Lookup tool.

With BIMI you achieve visual trust; with MTA-STS, infrastructural trust. Both protocols are “next-generation” standards that lift your business email reputation not just in the eyes of antispam filters but directly in the eyes of your customers.

If you are looking for a secure, professional business email solution that complies with these standards, you can get in touch about our services.