# Using internal threads over email > Internal threads let your team discuss a conversation privately the customer never sees it With Internal Threads over Email agents can loop in people out Source: https://help.kustomer.com/en_us/using-internal-threads-over-email-HJCQgVH4fe Last updated: 2026-07-23T15:45:32.749Z Internal threads let your team discuss a conversation privately — the customer never sees it. With **Internal Threads over Email**, agents can loop in people _outside_ Kustomer (a vendor, a partner, a subject-matter expert) by email, straight from the thread. The outside person gets a normal email, and when they reply — attachments included — their reply lands right back in the internal thread. Nothing about the exchange is ever visible to the customer. ### Prerequisites Your org must have **at least one email address set up** in the email channel settings. ### Toggling internal threads on To turn on internal threads, click **Settings>Administration>Organization**, scroll to **Internal Threads** and toggle this option to turn it on. This setting toggles on internal threads, which can be used via Email and Slack. ![](https://cdn.kustomerhostedcontent.com/media/570fad9d9001bc1000163b28/32b1bb04bc9c04292eb002640f65c0e9.png) Next, toggle on **Internal threads over email** to enable internal threads. Next, you'll need to configure the authorized email domains that should be able to receive these internal threads.  ### Managing settings for internal threads Settings for internal threads manage: * Allowed recipient domains. * The list of recently used recipients. * Adding suggested recipients. * Sharing of certain types of content. To manage settings, visit **Settings > Channels > Email**, and then click the **Settings** tab.  ![](https://cdn.kustomerhostedcontent.com/media/570fad9d9001bc1000163b28/90b97501ccff7862fe832fe063f78044.png) #### Allowing recipient domains Allowed recipient domains allow your team to securely manage who can receive internal threads via email. The system stops users from attempting to send emails to domains not allowed in this list. To authorize domains: 1. From the left navigation panel, click **Application Store**.   2. Beneath **Channels**, click **Email**.  3. Click **Settings**, and scroll to **Internal Threads.**  4. Enter the domain names that your internal threads can send to. Press the ENTER key after entering a domain to enter it into the list of authorized domains.  #### Managing suggested recipients List email addresses in this field to make those addresses suggested recipients, which are displayed in the rep's composer as suggestions.  To remove a suggested recipient, click the **X** next to that recipient's email address.  #### Managing recently used recipients Recently used recipients are listed beneath suggested recipients. This list is also visible in the composer as part of the suggested email recipient list.  Click **Clear** beneath the list of suggested recipients to clear this list at any time.  #### Controlling how internal threads are shared over email Toggling any of these settings allows sharing of specific content types: * Include conversation context in the first email. Context includes: * Who sent the internal thread. * The thread's title. * The thread's channel. * The number of messages in the thread.  * The status of the thread (whether it is open or closed).  * Who the thread is assigned to.  * Include conversation history in the first email. * Include new conversation activity in later emails.  ### Using internal threads in conversations An internal thread can exist in any conversation. It is a thread between the conversation (and all reps that have access to it), and the recipient(s) of the email.  To use internal threads: 1. Open a conversation and click **Add Internal Threads**. 2. From the **Share in** dropdown, select **Email.** 3. In the **To:** field, enter the email address(es) that should receive the message.  1. Suggested emails are listed when interacting with this field.  2. This field accepts more than one email address. 3. Email addresses listed here must be from domains you have approved as a recipient.  4. In the **Name** field, enter a name for the internal thread.  5. Write your message. 6. Click **Send**. Replies appear within the internal thread, under their name. Attachments work in both directions. The entire exchange is transferred as a single email conversation to the recipient(s), and exists as a continuous thread within the customer conversation on the timeline.  #### What the recipient sees ![](https://cdn.kustomerhostedcontent.com/media/570fad9d9001bc1000163b28/1dd1eff9ed5859a9dc0caa1d5e3838b4.png) * A friendly sender name — **"‹Agent name› (Internal Thread)"** — from the email address managed by your org. Replying just works. * A clean, Kustomer-branded message (a purple message bubble with a short note that replying will respond in the thread). It never uses your customer-facing email branding. * On the **first email only**, a context card summarizing the conversation: who the customer is, the conversation's status and assignee, and — if your org has Kustomer's AI features — an **AI-generated summary**. Below that, the **recent conversation history** is included in a collapsible quoted section (email apps tuck it behind "show trimmed content"), so the outside person has the full picture without a wall of text. * No links back into Kustomer — recipients are external and do not get access to your workspace. ### FAQ **Can I turn off internal threads?** Yes, this is possible when you visit **Settings>Administration>Organization** and toggling **Internal Threads** off. Turning this feature off will allow existing threads to persist, but will prevent new threads from being created or replied to.  **Can I email anyone, even someone outside my org?** Any agent can email any address from your list of allowed domains. There's no per-thread or per-team restriction. **Do internal threads generate summaries of the existing conversation?** An AI conversation summary is available in the first outbound email of an internal thread if your org has [**Enabled AI features**](https://help.kustomer.com/en_us/using-the-ai-agent-team-assistant-to-build-better-ai-agents-B1s6VhVebl). Without this setting, the email still includes a context card and conversation history.  **I can't see responses in my email.**  Brand-new sending domains can land in spam folders at first; check your spam folder. Email deliverability improves as your domain builds reputation.