Inbound email action processing

  • Release version: Zurich
  • Updated July 31, 2025
  • 6 minutes to read
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    Summary of Inbound email action processing

    Inbound email action processing in ServiceNow enables your instance to automatically handle incoming emails by matching them to specific inbound actions based on email type, subject prefixes, and conditions. This feature ensures that emails are correctly processed to create or update records, such as incidents, efficiently and accurately.

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    The system prioritizes inbound email flows triggered by email before processing inbound email actions. It evaluates inbound actions sequentially by their order, running only those that meet all criteria, including matching email type, valid watermark or record number, and condition evaluation.

    Key Features

    • Email Type Matching: Inbound actions run only if the email type matches the inbound action type.
    • Watermark and Record Number Matching: Emails containing recognized watermarks or record numbers in the subject or body link to existing records in the target table.
    • Reply and Forward Prefix Recognition: The system identifies email replies and forwards using configurable subject prefixes defined in system properties (glide.email.replysubjectprefix and glide.email.forwardsubjectprefix).
    • Configurable Prefixes: You can customize recognized prefixes to support non-standard email clients or processes, ensuring accurate reply or forward identification.
    • Forwarded Emails as Replies: Properties allow processing forwarded emails as replies to unify handling and updating of records like incidents.
    • User Matching: The sender's email address is matched to an active user in the User [sysuser] table to set the current user context for inbound actions, enabling personalized processing.
    • Watermark Transition Support: Both randomized and non-randomized watermarks are recognized during upgrade transitions.

    Practical Guidance for ServiceNow Customers

    • Define multiple case variations of reply prefixes (e.g., RE:, Re:) to ensure emails are consistently recognized.
    • Avoid including multiple record numbers in email subjects, as the system cannot predict which record to associate the email with.
    • Ensure user email addresses are unique or assign shared addresses to only one active user to avoid ambiguity in sender matching.
    • Be aware that unexpected characters (e.g., quotation marks) adjacent to record numbers in subject lines may prevent correct record matching, leading to creation of new records instead.
    • Use the inbound email action ordering and “Stop processing” flags to control workflow and prevent unnecessary action execution.

    Expected Outcomes

    By configuring inbound email action processing appropriately, your ServiceNow instance can:

    • Automatically link incoming emails to existing records via watermarks or record numbers, streamlining updates.
    • Correctly identify replies and forwards to trigger the proper inbound actions, reducing manual intervention.
    • Accurately match senders to users to personalize and secure email-driven processes.
    • Handle a variety of email formats and prefixes through property customization, improving compatibility with diverse email clients.

    This leads to more efficient incident management and record handling, with emails processed consistently according to your organization's needs.

    The system determines which inbound actions to run by comparing the inbound email type and inbound action conditions to the incoming email message. Certain properties are available to set the reply and forwarding prefixes in the email subject lines that your instance recognizes when processing inbound emails.

    Note:
    Inbound email flows take priority over inbound email actions. If you create flows with inbound email triggers, emails are first processed by the inbound email triggers before they are processed by inbound email actions.

    The system follows this processing flow to determine whether to run an inbound action.

    Figure 1. Inbound action processing workflow
    Inbound action processing workflow
    The system only runs an inbound action when:
    • The incoming email type matches the inbound action Type.
    • If present, the watermark or record number refers to a record in the Target table.
    • The inbound action Conditions evaluates to true.

    If any of these criteria are not met, the system skips the current inbound action and evaluates the next active inbound action. The system processes inbound actions from the lowest to highest Order value. If the inbound action has Stop processing enabled, the system updates the State of the email record to Processed after running the inbound action Script.

    Prefixes recognized in email subject lines

    Email reply prefixes
    When no watermark is present or the In-Reply-To email header is present, the instance recognizes email containing a prefix from the glide.email.reply_subject_prefix property as reply email. You can use this property to set non-standard reply prefixes in your email system.
    Property Description
    glide.email.reply_subject_prefix Specifies the comma-separated list of prefixes in the subject line that identify an email reply.
    • Type: string
    • Default value: re:,aw:,r:,Accepted:,Tentative:,Declined:
    Note:
    The case of the reply prefix in the email, for example RE:, must exactly match the case of the prefixes defined in this property. If, for example, an email contains the Re: prefix and only RE: is defined in the property, the email will not be recognized as a reply. Therefore, it is a best practice to define multiple versions of the prefix, including mixed-case versions, such as RE:, Re:, and so on.
    Email forward prefixes
    Emails with certain prefixes trigger the forward type of inbound email action. The instance recognizes any email whose subject line contains a prefix from the glide.email.forward_subject_prefix property as forwarded email. Emails with these prefixes trigger inbound email actions of the type forward. Use this property to set non-standard forward prefixes in your email system or you want email forwards to behave like replies. If the value of the system property is empty, then the system reverts to using the values fw: and fwd:.
    Property Description
    glide.email.forward_subject_prefix Specifies the list of prefixes (comma-separated) in the subject line that identify a forwarded email.
    • Type: string
    • Default value: fw:,fwd:
    • Location: Add to the System Properties [sys_properties] table
    Note:
    Prefixes are case insensitive.
    Email forwards as replies
    Properties are available to force inbound actions to process forwarded mail as replied mail. These properties control the subject prefix that the inbound actions use.
    Property Value needed
    glide.email.reply_subject_prefix re:,Re:,RE:,aw:,r:,fw:,fwd:,Fwd:,FWD:
    glide.email.forward_subject_prefix [any text that is not a forward prefix]
    These properties cause the Update Incident inbound action to process all forwarded and replied-to mail.
    Note:
    The glide.email.forward_subject_prefix property must contain some text so that the forwarded email can be processed as a Reply. It can be any text except a forward prefix (that is, fw:,fwd:,Fwd:,FWD:).

    Matching a sender email address to a user

    The instance matches a senders email address to an active user in the User [sys_user] table using inbound actions.

    When processing an email, the instance sets the current user to the user whose email address matches email.from. Inbound actions can then reference that current user. For example, the base system inbound action Create Incident sets the caller_id of the incident to the value returned by gs.getUserID().

    If multiple users have the same email address, the instance first searches for an active user with the email address. The instance does not match inactive users.

    Note:
    Each user record must have a unique email address so that the instance can reliably match the email to the correct user.
    If a unique email address for each user is not possible, assign a shared email address to only one active user so that the instance always matches incoming email from that address to the active user.

    Matching watermarks in the Subject line or Body

    The following examples illustrate how the instance matches randomized watermarks in an email subject line or body.

    Note:
    For instances upgraded from a release before Jakarta, the system can recognize both randomized and non-randomized watermarks during a watermark transition period.
    Table 1. Examples of matching watermarks in the Subject line or body
    Subject Line or Body Contents Matching Results
    Ref:MSG0000008_ aLJc130zDhCVuh3spXmt The instance recognizes this string as a watermark and searches the Email Watermarks [sys_watermark] table for a record with the number MSG0000008_ aLJc130zDhCVuh3spXmt. If this watermark exists, the instance matches the email to the associated record. If this watermark does not exist, the system processes inbound email messages as described in .
    Ref:MSGWTR0000008_wfLLz42IxCgUvG2JlYnh The instance recognizes this string as a watermark and searches the Email Watermarks [sys_watermark] table for a record with the number MSGWTR0000008_wfLLz42IxCgUvG2JlYnh. If this watermark exists, the instance matches the email to the associated record. If this watermark does not exist, the system processes inbound email messages as described in .

    Matching record numbers in the Subject line or Body

    The following examples illustrate how the instance matches record numbers in the subject line of an email to an existing record when no watermark is present.

    Table 2. Examples of matching record numbers in the Subject line
    Subject line contents Matching results
    RE: Example INC0005574 The instance recognizes this subject line as a reply and recognizes the INC prefix as belonging to the Incident table. The instance searches the Incident table for an existing record INC0005574. If this incident exists, the email is associated with this incident. If this incident record does not exist, the instance uses the inbound action for new emails to create an incident and associates the new incident with the email.

    RE: Example "INC0005574"

    RE: Example *INC0005574

    		 The instance recognizes this subject line as a reply but does not recognize the "INC prefix as belonging to the Incident table because of the quotation mark. The same error occurs for any character other than a space before the record number. The instance instead uses the inbound action for new emails to create an incident and associates the new incident with the email.

    RE: "Example INC0005574"

    RE: Example INC0005574*

    		 The instance recognizes this subject line as a reply and recognizes the INC prefix as belonging to the Incident table. The instance searches the Incident table for an existing record INC0005574", which it cannot find because of the quotation mark. The same error occurs for any character other than a space at the end of the record number. The instance instead uses the inbound action for new emails to create an incident and associates the new incident with the email.
    RE: CHG0008593 and INC000576 The instance recognizes this subject line as a reply and recognizes one, but not both, of the number prefixes. There is no way to predict which prefix the instance matches first. Whichever prefix it matches, it searches the corresponding table for a matching record. If the record exists, the email is associated with the table. If the record does not exist, the instance uses the inbound action for new emails to create an incident and associates the new incident with the email.
    Note:
    The instance does not support processing email with multiple numbers in the subject line because there is no way to predict which record the instance matches first. For this reason, do not include more than one $number variable in your notifications.
    FW: Example INC0005574 The instance recognizes this subject line as a forward because of the FW: prefix. It uses the inbound action for forwarded emails to create an incident and associates the new incident with the email.
    Example INC0005574 The instance recognizes this subject as a new email because it does not contain a matching reply or forward prefix. It uses the inbound action for new emails to create an incident and associates the new incident with the email.