Check What the Inbox Extracts as Preview Text

Approve the text that appears beside a Migma email's subject in the inbox, not just the preheader stored in the editor. An empty override, an exported wrapper or a short snippet can expose nearby message text that the campaign author never intended as its introduction.

Editorial disclosure: Prepared by Marketing Wiki Research Automation under standing direct-publication authorization and not independently reviewed. Product capabilities are vendor-documented unless labeled otherwise; sources were refreshed on September 15, 2026.

Affiliation disclosure: Marketing Wiki’s commissioning maintainer also maintains Migma. This article is prepared by Marketing Wiki Research Automation under explicit direct-publication authorization and is not independently reviewed.

Migma's viewer and campaign guidance documents subject and preheader overrides. We recommend reviewing the final campaign fields and the received inbox row together. The body preview alone cannot show which text a particular inbox chooses to extract.

Build a contamination fixture#

Use a fictional workshop message with deliberately different text at each boundary:

Subject: Build your first customer interview guide
Intended preview: Bring one research question to Thursday's workshop.
First body heading: A practical session for product teams
First utility link: View this email online
Internal fixture marker: SNIPPET-CHECK-ONLY

Keep the internal marker in a private test artifact only, never in a production send. Its purpose is to reveal accidental inclusion while testing. Avoid real confidential notes, personal data or unreleased information in the fixture.

Mailchimp's preview-text documentation explains that clients may pull the message opening when custom preview text is not set. It also notes that the amount shown varies. That supports checking extraction, but it does not establish one safe character count for every inbox.

Inspect four versions of the same message#

Start with an explicit, useful preheader. Then test an empty preheader, a very short one and a destination override that differs from the original Migma text. Label each case and keep the subject and body constant. This isolates the extraction behavior from a broader copy test.

For each case, record the sender name, complete subject, displayed snippet, inbox app and available row width. Include whether the app displays one or more preview lines. A snippet that appears correct in a wide desktop row may end at a different point in a narrow mobile view.

The question is not whether the entire preview sentence always appears. It is whether the portion that appears remains accurate and useful, and whether unrelated utility or internal text appears after it.

Diagnose where the wrong text entered#

If the wrong sentence is stored in the final campaign's preheader field, repair that field. If the field is correct but the inbox shows body text, inspect the final HTML and destination's treatment of preview text. If only one client differs, preserve that observation instead of overwriting every version without a hypothesis.

Migma's export workflow requires final review in the receiving platform. Check that platform's subject and preview settings even when the design imported successfully. A successful visual handoff does not establish that campaign metadata transferred with the same values.

Do not attempt to repair extraction by adding enormous runs of invisible filler without reviewing the resulting source and client behavior. Such changes can enlarge the HTML or produce unexpected artifacts. Prefer a useful explicit preview sentence and a sensible first body line, then test the exact sending path.

Write the first phrase to survive truncation#

For the workshop example, “Bring one research question” communicates useful preparation before the rest of the sentence appears. A preview beginning “You won't believe what we have planned” consumes scarce space without clarifying the message. That is an editorial judgment, not an open-rate prediction.

Keep the subject and preview complementary. If the subject promises a workshop, do not use the snippet to introduce a different offer or a condition that disappears when truncated. Material conditions must remain clear in the body and destination as well.

Close with an extraction receipt#

Retain the final field value, final HTML revision, screenshots of declared inbox rows and any known client exceptions. Remove the private fixture marker before release and search the final source to confirm it is gone. Recheck the snippet after changing the first body block or destination template.

This differs from the subject-line hypothesis register, which evaluates a planned experiment. Here the release question is whether the inbox exposes the intended words at all. No inbox or sending account was tested for this article. Add one extraction fixture to your next authorized review and keep its evidence separate from campaign performance.