Email Security Blog

API vs. Inline - What You Need to Know

Entering the email security business is not a decision for the faint of heart. It’s a competitive industry where your greatest adversaries – namely cybercriminals – are continually trying to outsmart the very platform you’ve built to stop them. So why would anyone want to enter the market? The answer is simple: to make a difference. For INKY, this meant looking beyond the existing (and unexceptional) solutions to find a better science. One piece of that puzzle was deciding which email deployment model is most effective – API or Inline.

To determine which approach was best, INKY built and tested three implementation models – API, Inline, and full Secure Email Gateway (SEG) with MX redirect.

Application programming interface, commonly known as API, is a software intermediary that allows two applications to talk to each other. In the world of email security services, API solutions are commonplace, and they access the inbox through the backend storage. However, due to a nearly simultaneous sync, the email races to the recipient’s inbox, outpacing more thorough security measures. API does have its advantages as it is easy to implement, simple to deploy, and it’s relatively painless for developers without a great deal of email technical knowledge to understand.

SEG with MX redirect deployments are painful: they require changing the public DNS records for all email, to route the mail to a third party. However, if that third party is down, the customer’s mail simply won’t be delivered!

Inline solutions are positioned between the email transport engine and the back-end cloud mail store, allowing the email to be thoroughly (yet instantly) examined before it reaches a recipient’s inbox. While Inline solutions do require more skill and knowledge to create, they offer several advantages over API.

INKY’s inline position allows it to unleash more than three dozen models simultaneously on every email that passes through. This high-level analysis uses computer vision, artificial intelligence, and machine learning to see – and catch – everything. Then, based on the result of its analyses, INKY’s Email Assistant injects an HTML block with one or more of nearly 60 simple-to-understand email security warnings banners into the email between the header and the body. In this way, the Email Assistant provides gentle but persistent cues whenever it detects something is amiss. This provides clear context and continually educates your employees, training them on what to look out for and easing the burden on your IT department. As an added extra, INKY’s Email Assistant can remove the warning block from any outgoing replies.

At INKY we started without a dog in this fight: we explored all three deployment methods (API, MX, and inline downstream) and landed on our standard model simply because it works the best for most customers.

To truly have a handle on securing your company’s email, you need a third party’s assistance. INKY’s Inline positioning allows for a relentlessly effective level of email security, capable of detecting and eliminating the greatest cybersecurity threats, including phishing and malware.

If you’d like to learn more about API vs. Inline-based solutions, we encourage you to read our guide entitled, API vs. Inline – Which Deployment Model is Right for Me? Then, be sure to sign-up for a free INKY demonstration so you can see the dozens of other benefits of INKY’s design.

Schedule your INKY demonstration. 


INKY is an award-winning, cloud-based email security solution developed to proactively eliminate phishing emails and malware while simultaneously providing real-time assistance to employees handling suspicious emails so they can make safer decisions. INKY’s patented technology incorporates sophisticated computer vision, machine learning models, social profiling, and stylometry algorithms to effectively sanitize emails, rewrite malicious links, detect and block security threats, mitigate sender impersonation, and more. Cost-effective and powerful, the INKY platform was developed for mobile-first IT organizations and works seamlessly on any device, operating system, and mail client. Learn more about INKY™ or request an online demonstration today.