What is email threading?

An email thread is an email conversation that starts with one message and includes all replies and forwards connected to that message. An email thread consists of one long email conversation containing all messages and replies related to the original email. Sifting through multiple emails to piece together a discussion can be a frustrating experience for users.
Email threading is the technique that groups this chain of messages, giving users an organized view of each email conversation.

hero banner

If you are a developer thinking about integrating email functionality into your app, read on to learn more about email threading, its benefits, and its challenges. Want to learn more about the value of threading in an email API? Check out this post.

Challenges of email threads

As the number of emails generated and received by the average company grows, it becomes increasingly difficult to manage email threading. To compound the problem, emails usually don’t have metadata identifying them as part of a specific thread, so it’s up to the email client to determine how to group emails and display the threads. 

How the thread is displayed depends on the user interface of the email client, which may cause display issues. Therefore, building an email threading feature in an application with email capabilities can be time- and resource-consuming. 

Email threading in an application

Incorporating email threading into an app can be extremely useful for end users, as it reduces confusion in the inbox, preventing users from sifting through countless emails and enhancing your app’s user experience. 

Despite how useful email threading features are, implementing them in widely known email clients can be cumbersome and time-consuming. To add email client functionality to your application, you need to configure the settings and options for each client, such as how to group the threads, which messages to show and which to hide, and how to mark the threads. All these require considerable time and effort. 

A simpler alternative is using an email API like Nylas that supports multiple integrations. Nylas simplifies email threading across clients, so you don’t need to set them up individually. Nylas integrates with every email provider including Gmail, Microsoft Exchange, MS Office365, Microsoft Graph, Outlook, iCloud, and IMAP. Check out the complete list of supported email providers with Nylas.

Benefits of email threading in your application 

Adding an email threading capability to your application provides many benefits for users and product teams. Of course, for both, there are some considerations to be aware of. Let’s take a closer look:

Benefits for end users 

Keeps all recipients informed
By grouping all emails related to the original one, all recipients are in the same loop. This feature then enhances communication, especially for business and commercial applications. For instance, customer service apps may benefit from email threading by keeping all communications related to one customer’s ticket in the same place. Customer service agents can see a holistic view of a customer’s conversation, enabling them to reply or resolve issues with accuracy and efficiency. 

Enhances the user experience
Simplified email threading helps end users understand the key messages in the thread, so it’s easy to follow the conversation. This can be a valuable feature for technical support teams in an application, as it allows agents and users to follow the entire ticket process in a single place. 

Reduces inbox clutter
Email threads simplify inbox management by keeping all the connected messages in one place. Users can scan through a thread and find the information they need without having to scour the entire mailbox, as well as search and filter emails by keyword. Email threading reduces email duplication and saves users from having multiple emails related to the same subject. 

Considerations when building email threading
Some recipients may get irrelevant emails. Not all the emails in a thread may be relevant to all the recipients. In a long thread, some emails may be relevant only to a portion of the recipients. 

Emails can get convoluted
Some threads can get too long and convoluted to be followed easily by users. Also, if users delete an email in the thread, it can delete other emails that may be important. 

Benefits for product teams 

Simplifies e-discovery
E-discovery is a type of digital investigation that attempts to find evidence in emails to use in criminal or legal processes. The evidence may include data from instant messages, email accounts, and other online documents. Email threading is an essential tool for e-discovery, as it can provide key information in cases of data breaches. 

Emails can have dozens or hundreds of segments, some of which are important for an investigation and many of which may be irrelevant. Reviewers benefit from email threading because it allows them to see the inclusive messages and get the whole conversation in one place. 

Simplifies email analytics
Email threading detects and correlates the relationship between emails, normalizing email metadata. This feature simplifies email analytics, such as for security purposes. 

Saves developers time and resources
Integrating an email threading API reduces most of the building work by giving a single, integrated solution. The development time and resources needed decrease dramatically. 

Considerations when building email threading for product teams
Email threading is not universally supported. Some email providers — such as Gmail and Outlook — don’t support email threading, so the options for setup in an app can be limited.

Build with the Nylas Email API

Focus on your business strategy, NOT on infrastructure. Investing in pre-built productivity tools frees up resources so your team can focus on building unique features your customers love.

Speak to a specialist

How does email threading work?

An email threading feature analyzes and identifies elements of an email, looking for connections between them, and then groups the emails together into a continuous thread. Here is how it works: 

Step 1. First, a text analytics algorithm in the email threading functionality examines a data set and identifies segments — parts of the conversation — within the data set. The algorithm compares the segments, looking for similarities that indicate they belong to the same conversation. 

Step 2. The email threading algorithm next determines which type of communication exists in the embedded messages inside the emails, such as whether each is a reply, a reply-all, or a forward. 

Step 3. The email threading functionality then correlates and groups the emails and attachments. When the algorithm matches the segments, it groups the emails and attachments into a neat thread, called a thread group. 

Step 4. The algorithm then analyzes variables in the thread group. The email threading functionality will analyze and normalize the header data, including dates, senders, and recipients in the original email and subsequent messages, as well as sent time, attachments, and email text, to determine if the emails are inclusive (they contain all the text and attachments) or non-inclusive (a single reply or the last message in a thread). 

Email threading with an email API 

Developers integrating email capabilities into an application aim to provide a consistent and easy-to-understand view of email conversations. An API solution can simplify email threading by establishing which messages belong to which threads. Deleting and archiving messages can also be done individually or as part of a thread.

The Nylas Email API integrates with the user’s inbox, providing bi-directional email. Building a threaded email inbox view will help your users access their email data from within the application.  

Ship faster with the Nylas Email API 

No more convoluted and difficult-to-group threads. The Nylas Email API takes care of this complexity by offering an all-in-one solution that simplifies email threading and connects all email, calendar, and contact service providers with yourapplication. It uses REST APIs to take the hassle out of building email threading algorithms, allowing you to deploy your engineering resources towards other critical work. 

Discover how the Nylas Email API makes it easier to build a threaded email inbox. Request your free API key and start building. 

Frequently asked questions

What is a threaded message?

A threaded message is a message within a thread. Messages before any replies are called “unthreaded messages,” and the message that gives origin to the thread is called a “parent“ message. The replies are also called “child messages.” 

How does email threading handle unsupported header languages?

Typically, when headers are in unsupported languages, the groups of emails in a thread are split into multiple threads according to the language used. 

How do email clients track conversation threads?

Email clients match in-reply-to and message-ID headers to identify which thread corresponds to what email. 

What’s the role of email threading in email security?

Email threading is essential for email security processes, such as review and forensic analysis. An email thread groups all connected documents from an email conversation, including attachments. This simplifies the reviewer’s task by identifying inconsistencies or discrepancies.  

What are indentation levels and their role in the email threading ID?

Messages inside a thread are assigned an order number and an indentation level that goes both in the document and in the visualization field. The indentation aims to create a visual separation between the different email segments. 

Nyla waiving Nylas flag

Ready to get started?

Unlock your API key and sync up to 10 accounts.

Additional Resources

10 Best Email APIs in 2023
10+ Best Email APIs in 2023 for Developers [Free & Paid]
hero banner image for blog post
5 Ways to Improve Email Deliverability
How to Create a Mail Merge Template with Ruby

Ready to start building?

Contact us to schedule a technical consultation. We’ll review your goals and help you identify the best solution with the Nylas platform.