# Invitation Piping Tags Following piping tags can be used within your invitation message, these tags will be replaced dynamically by ngSurvey for each recipient before the invitation is send out. * **`[--surveyid--]`** survey id to which the respondent is invited to. Some piping tags are only available to some [distribution](/form-management/campaigns/campaign.md) options. ## 📧 Email distribution invitation message * **`[--invitationid-]`** is the unique generated code that grants access to the survey and uniquely identify the recipient. * **`[--invitationtoken--]`** will be replaced by either a random taken token from your pre-generated [token](/form-management/security/security-items/tokens.md) list or if ngSurvey matches an unused token with an email that is the same as the recipient email it will use that token. ## 👪 Panel distribution invitation message * **`[--panelistid-]`** is the [panelist](/panels/panelists.md) id of the panel member. * **`++panelattribute++`** will be replaced by the [panelist](/panels/panelists.md) value of that [panel attribute](/panels/untitled.md). The panelattribute in the tag must be replaced by the mailing pipe alias of the [panel attribute](/panels/untitled.md) of your choice. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.ngsurvey.com/form-management/campaigns/campaign/invitation-message/invitation-piping-tags.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.