Email is one of the most common ways cybercriminals target businesses. Traditional email security tools can block many threats, but some malicious emails still reach users’ inboxes. This is where API-based email security comes in. An Application Programming Interface (API) allows two software applications to communicate and share data.<\/p>\n\n\n\n
In the past, many businesses hosted their own email servers and used secure email gateways (SEGs) to check messages before they reached employees. Today, more organizations rely on cloud email services such as Microsoft 365 and Google Workspace, which have changed how email security works. Although traditional gateways still play an important role, they mainly check emails as they pass through them. <\/p>\n\n\n\n
Let\u2019s say an email looks harmless at first. A few hours later, the security team discovers that the sender’s domain is linked to a phishing campaign. The email has already been delivered, and an employee may have clicked the link.<\/p>\n\n\n\n
So what happens when a threat is discovered after a message reaches an employee’s inbox?<\/p>\n\n\n\n
In such scenarios, API-based email security gives businesses another way to handle these threats. By connecting directly to the email platform, it can help security teams find and remove malicious messages even after delivery, depending on the solution’s features and permissions.<\/p>\n\n\n\n
In this blog, we’ll explain what API-based email security is, how it works, how it compares with secure email gateways, and what businesses should consider before choosing a solution.<\/p>\n\n\n\n
API-based email security protects email accounts by connecting a security tool directly to an email service through an API. In simple terms, an API helps two applications share information and work together.<\/p>\n\n\n\n
Traditional secure email gateways inspect emails as they pass through before they reach their destination. API-based solutions work differently. They connect to email platforms such as Microsoft 365 and Google Workspace and use their APIs to check emails, links, attachments, and sender details.<\/p>\n\n\n\n
This helps security teams catch threats such as phishing, malware, spam<\/a>, and business email compromise (BEC)<\/a>. If a suspicious email slips into someone’s inbox, the security tool can flag it, move it to quarantine, or remove it. It can also alert the security team so they can investigate the threat.<\/p>\n\n\n\n Here is the step-by-step process of how API-backed email security accesses messages, checks against potential threats, and takes adequate security actions:<\/p>\n\n\n\n First, the security tool connects to an email service such as Microsoft 365 or Google Workspace through its API. The organization grants the permissions needed for the tool to check email data and take certain actions. These permissions control what the tool can access and do.<\/p>\n\n\n\n Once connected, the tool can access email data based on the permissions and features supported by the platform. This may include incoming and outgoing messages, sender details, email content, links, and attachments.<\/p>\n\n\n\n Next, the tool checks emails for signs of an attack. For example, it may find a link that leads to a fake login page, an attachment that contains malware, or a message asking an employee to send money to an unfamiliar account. Some tools also use machine learning to spot unusual patterns that could point to an attack.<\/p>\n\n\n\n If the tool finds a suspicious email, it can respond based on its settings and permissions. It may flag the message, move it to quarantine, or alert the security team. Some tools can also remove dangerous links or attachments, depending on their features.<\/p>\n\n\n\n Not every threat is caught right away. An email that looks safe at first may later be identified as malicious when new information becomes available. In such cases, the tool can use the email platform’s API to find and remove the message from inboxes, if the platform supports this action and the tool has permission to perform it.<\/p>\n\n\n\n Email security needs are changing, and businesses are moving operations to the cloud, so APIs are getting the attention they deserve. Below is a detailed explanation of the core reasons contributing to the pickup of this type of email security:<\/p>\n\n\n\n Email attacks aren’t always easy to spot. A message may look like it came from a manager, a supplier, or a company the recipient trusts. Attackers often use fake login pages, misleading links, or urgent payment requests to trick employees into sharing information or sending money.<\/p>\n\n\n\n The financial impact can be huge. The FBI’s 2025 Internet Crime Report<\/a> recorded about $3.05 billion in reported BEC losses. These attacks often involve criminals impersonating executives or trusted business contacts to request payments or sensitive information.<\/p>\n\n\n\n API-enabled email security can help businesses identify suspicious messages and investigate potential attacks. By accessing mailbox data, these tools can help security teams spot threats and take action before more damage is done.<\/p>\n\n\n\n Attackers don’t always need a malicious attachment to cause damage. Sometimes, a convincing email and a link to a fake login page are enough to steal an employee’s password. Cloudflare’s 2025 Year in Review<\/a> found that 5.6% of the emails analyzed by its email security service were classified as malicious, highlighting why businesses need to look beyond obvious signs of an attack. <\/p>\n\n\n\n An email can pass security checks and still be dangerous. For example, a link in the email might be marked as harmful only after researchers find out that it leads to a phishing website. By then, the email may have already reached several employees. Blocking the sender will stop future emails, but it won’t remove the ones already sitting in employees’ inboxes.<\/p>\n\n\n\n API-backed email security helps solve this problem. Depending on the tool and its permissions, it can find and remove harmful emails even after they have been delivered. This helps security teams deal with threats that were missed during the first round of security checks.<\/p>\n\n\n\n Many businesses use cloud platforms like Microsoft 365 and Google Workspace to manage their emails. These platforms have built-in security features, but some businesses may need extra protection based on their size, risks, and security needs.<\/p>\n\n\n\n API-based email security tools connect directly to the email platform instead of checking emails only as they pass through a security gateway. With the right permissions, these tools can access mailbox data and investigate suspicious emails. This makes them a good fit for businesses that use cloud email. They can add another layer of security without necessarily changing how emails are delivered.<\/p>\n\n\n\n Adding a new email security tool can be a hassle if it means changing the existing email setup. Traditional secure email gateways may require changes to MX records, mail routing, and other settings before they can start working.<\/p>\n\n\n\n API-based solutions work a little differently. They connect directly to platforms like Microsoft 365 and Google Workspace, usually through an authorization process. They don’t sit in the path of incoming and outgoing emails, so businesses may not need to make major changes to their mail flow.<\/p>\n\n\n\n This can make setup easier for IT teams that want to improve email security without messing with their existing setup. Of course, the amount of work involved still depends on the tool and the organization’s environment.<\/p>\n\n\n\n Choosing the right tool is only the first step. How you set it up, manage access, and respond to alerts will also affect how well it protects your organization.<\/p>\n\n\n\n Don’t choose a security tool just because it has lots of features. Check how well it works with your email platform, which threats it can detect, and what actions it can take when it finds a suspicious message. Vendor support and clear documentation matter, too, especially when your team needs help with setup or troubleshooting.<\/p>\n\n\n\n Every business has different risks, so your security settings should reflect the threats you are most likely to face. For example, you may want closer checks for unexpected payment requests, suspicious links, or emails from unfamiliar senders. Review these rules regularly. If they’re too strict, employees may struggle to access legitimate emails. If they’re too relaxed, threats could slip through. <\/p>\n\n\n\n Email threats change, and security tools need regular updates to keep up. Check that your provider maintains its threat detection features and fixes security issues when they arise.<\/p>\n\n\n\n Also, keep an eye on changes to the email platform’s API. Updates to permissions or supported features can affect how your security tools work. If you use a DMARC API<\/a> to send authentication data to other security systems, review that integration regularly to make sure the data is still flowing correctly.<\/p>\n\n\n\n Even with security tools in place, employees need to know what suspicious emails look like. Teach them to be careful with unexpected payment requests, unusual login links, and messages that pressure them to act quickly.<\/p>\n\n\n\n Make sure they know how to report suspicious emails, too. Their reports can help the security team investigate threats that automated tools may have missed and check whether similar messages have reached other inboxes.<\/p>\n\n\n\n Before enabling the solution for everyone, test it with a small group of users. This helps you see how it handles real email traffic and whether it flags legitimate messages by mistake. Use the results to fix any issues before expanding the rollout. Once the solution is in place, continue checking its performance and adjust the settings as your organization’s needs change.<\/p>\n\n\n\n Installing a security tool is only the beginning. Your team should review alerts, investigate suspicious activity, and check whether the solution is catching the threats it is designed to detect.<\/p>\n\n\n\nHow Does API-Based Email Security Work?<\/strong><\/h2>\n\n\n\n
Step 1: Connect to the Email Platform<\/strong><\/h3>\n\n\n\n
Step 2: Check email activity<\/strong><\/h3>\n\n\n\n
Step 3: Look for suspicious signs<\/strong><\/h3>\n\n\n\n
Step 4: Take action against threats<\/strong><\/h3>\n\n\n\n
Step 5: Remove threats found later<\/strong><\/h3>\n\n\n\n
Why Are More Businesses Turning to API-Based Email Security?<\/strong><\/h2>\n\n\n\n
Email Attacks Can Cost Businesses Billions<\/strong><\/h3>\n\n\n\n
Phishing Emails Are Getting Harder to Spot<\/strong><\/h3>\n\n\n\n
Threats Can Be Discovered After an Email Is Delivered<\/strong><\/h3>\n\n\n\n
Cloud Email Needs a Different Approach to Security<\/strong><\/h3>\n\n\n\n
Businesses Want Easy Setup Without Changing How Email Works<\/strong><\/h3>\n\n\n\n
Best Practices for Implementing API-Based Email Security<\/strong><\/h2>\n\n\n\n
Choose a Solution That Fits Your Needs<\/strong><\/h3>\n\n\n\n
Set Security Rules That Work for Your Business<\/strong><\/h3>\n\n\n\n
Keep the Integration Updated<\/strong><\/h3>\n\n\n\n
Help Employees Recognize Suspicious Emails<\/strong><\/h3>\n\n\n\n
Test the Solution Before a Full Rollout<\/strong><\/h3>\n\n\n\n
Review Alerts and Security Reports Regularly<\/strong><\/h3>\n\n\n\n