Outlook Add-in Visual Preview capabilities and tradeoffs

Overview

Visual Preview is one of three deployment methods for the Opensense Outlook Add-in. When it is turned on, the add-in renders a live HTML signature inside the Outlook compose window, so users see their signature while composing. This article covers how Visual Preview works, what it supports, and where its boundaries are, so admins can make an informed decision about whether it fits their organization’s requirements.

Compare the methods first

If you haven’t reviewed the deployment methods side by side, start with the Outlook Add-in overview or Comparing Outlook Add-in deployment methods before you read this article.

How Visual Preview works

When a user opens a new compose window in Outlook, the add-in renders their assigned HTML signature and inserts it into the compose window. The signature is applied client-side, and exists in the email body before the user sends.

Because the signature is in the compose window, the user can see it and change it throughout composition. When the email is sent, it goes to the recipient with the signature as it is. It doesn’t route through Opensense servers for transformation.

What Visual Preview supports

1. 01
   Compose-window visibility

   Users see their full rendered HTML signature, including any banners, while composing. This is the main reason organizations choose Visual Preview: employees have clear confirmation that their signature is active on every email.

2. 02
   Automatic signature insertion

   The add-in inserts the signature automatically on every new compose, reply, and forward when Automatic Signatures is turned on in Domain Settings. No user action is required.

3. 03
   Sender-based banner targeting

   Banner campaigns can target the sender's attributes, including department, role, and group membership. Rules that target based on who is sending the email work as expected.

4. 04
   Basic analytics

   Views and clicks can be captured for banners when the HTML is coded to support it. This gives basic engagement data for banner campaigns.

5. 05
   Inline images

   Supported across all Microsoft 365 Outlook versions. Turn on Inline Images in Domain Settings, and add ?inline=1 to all image URLs in the signature HTML.

6. 06
   Reply and forward signatures

   Either one consistent template for all replies and forwards, or a designated reply template for reply and forward actions. Configure this through signature assignment and routing.

Tradeoffs to understand before choosing Visual Preview

Weigh these limits against what Visual Preview supports. The first three are the ones that most often decide the choice.

Compliance: users can edit the signature before send

Because the signature is inserted into the compose window before the email is sent, users can change it manually before sending, including text, formatting, layout, and content. Opensense doesn’t track, block, or flag those edits. The email reaches the recipient with whatever the user last left in the compose window.

This matters for organizations that use email signatures to enforce brand standards, deliver legal disclaimers, or maintain regulatory compliance. If signature integrity on every outbound email is a requirement, Visual Preview doesn’t provide that guarantee. Plain Text Block and Stamping apply the signature server-side, and users can’t edit it.

Compliance-sensitive organizations

If your signatures carry legal disclaimers, regulatory copy, or brand-governed content, evaluate whether user-editability is an acceptable risk before you turn on Visual Preview.

Marketing: recipient-based targeting is not supported

Recipient-based banner targeting isn’t available in Visual Preview. Opensense can’t determine recipient attributes at compose time, because the email hasn’t been sent yet. Targeting logic that relies on who receives the email can’t run until the message reaches Opensense’s servers, which Visual Preview bypasses.

Recipient-targeted campaigns

If your banner campaigns target recipient industry, account, or contact attributes, Visual Preview won’t support them. Stamping and Plain Text Block both support full recipient-based targeting.

Marketing: advanced analytics are not available

Because emails sent with Visual Preview don’t route through Opensense servers, advanced analytics aren’t available, including detailed banner engagement data beyond basic views and clicks. Organizations that run data-intensive banner campaigns, or report on campaign performance, should factor this into the decision.

Other limitations

First reply signature

A full signature on the first reply is only available with a routed method (Stamping or Plain Text Block). Visual Preview supports reply signatures, but its first-reply behavior differs from what routed methods deliver.

Multi-recipient signature logic

A message is assembled as one static object before it leaves the compose window, and every recipient receives an identical copy of that body. At no point during composition can there be one version of the message per recipient, so any logic based on who receives the email has to resolve to a single value while the message is still being written. That value ends up being the last recipient added to the email. This comes down to how an email is built before it's sent, not something specific to Opensense.

Third-party platform compatibility

The Outlook Add-in, with any deployment method, only applies signatures to emails composed in Microsoft Outlook. Emails sent through Outreach, Salesloft, Salesforce, or other third-party platforms aren't covered. For routed mail flow integration options for those platforms, see Third-party email platforms in the Outlook Add-in overview.

Outlook Mobile account switching

On Outlook Mobile, the add-in passes only the primary account context to the API. If a user switches the From address to an alias or shared inbox, the add-in doesn't update the signature for the switched identity. This applies to all add-in deployment methods, not only Visual Preview. It is a Microsoft platform limitation. For the canonical reference, see Outlook Mobile From switching in the Outlook Add-in overview.

Rendering across Outlook versions

Different versions of Outlook may render the composed signature differently. Some elements may be blocked, or display differently in the compose window, depending on the client version. Test rendering across your organization's Outlook versions before you roll out Visual Preview at scale.

When Visual Preview makes sense

Visual Preview is a reasonable choice when:

• Compose-window visibility is a meaningful priority for your employees or organization.
• Your banner campaigns use sender-based targeting, not recipient-based targeting.
• Advanced analytics aren’t a core requirement for your marketing team.
• The risk of user-edited signatures is acceptable, given your compliance requirements.
• Your organization sends encrypted emails through Microsoft sensitivity labels or other Microsoft 365 encryption policies. Opensense can’t process encrypted emails server-side, and Visual Preview is the only add-in method that delivers signatures on encrypted emails reliably.

Need compliance guarantees and full marketing?

If your organization requires signature compliance guarantees and the full Opensense marketing feature set, Plain Text Block gives signature visibility in the add-in pane with server-side control, without the compliance and marketing tradeoffs of Visual Preview. For a full comparison of all three methods, see the Outlook Add-in overview or Comparing Outlook Add-in deployment methods.

What’s next

• Comparing Outlook Add-in deployment methods
• Configuring the Outlook Add-in in Domain Settings
• Expected behaviors in routed Outlook Add-in deployments
• Troubleshooting the Outlook Add-in