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Email Subject Line Generator

The Email Subject Line Generator helps marketing teams quickly create subject lines and pre-headers for email campaigns. It uses AI-generated suggestions, applies content safety checks, and supports optional AMP script preparation workflows.

Accessing the Tool​

  • In the CMS sidebar, go to Copy.
  • Select Create Email Subj.
  • Open route pattern: /apps/:appId/email-subject-lines/create-new.
  • Access to this feature requires the copy feature key.
Email Subject Line Generator screen

How to Generate Subject Lines​

  • Enter your campaign idea in Subject Line/Pre-header Prompt.
  • Optionally add one or more entries in Brand Names.
  • Choose a Tone that matches your campaign goal.
  • Toggle Include Emoji on or off.
  • Optionally enable Include Results from Belk Model.
  • Set No. of Subject Lines (from 1 to 20).
  • Click Generate.
info

The Belk Model option is a legacy feature. Prefer the default generator output for standard usage unless your team still relies on legacy comparisons.

Form Values​

NameTypeDescriptionDefault
Subject Line/Pre-header PromptStringMain input that describes the campaign, offer, or message intent.Empty
Brand NamesArrayOptional multi-select brands to include in generated copy.Empty
ToneOptionOptional tone for style guidance (for example, exciting, urgent, love).Empty
Include EmojiBooleanControls whether generated output should include emojis.true
Include Results from Belk ModelBooleanOptional legacy result source for comparison.false
No. of Subject LinesNumberNumber of generated rows. Accepted range: 1-20.1

Understanding Results​

  • Results appear in grouped sections such as OpenAI and optional Belk Model output.
  • Each result includes Subject Line and optional Pre-Header text.
  • You can edit generated values inline before copying.
  • Character counts appear next to each field to help with email constraints.
  • Use Copy to copy individual entries and Refresh to regenerate a row.

Content Filtering and Formatting​

  • Block-listed words are highlighted with strikethrough formatting.
  • Profanity filtering is applied before final display.
  • Brand formatting preserves special trademark symbols where supported.
  • Output formatting enforces AP-style list handling for brand names.
  • The word "free" may be normalized to "FREE" in generated output.
  • Emoji formatting rules limit clustering and spacing issues.
tip

For better output quality, include concrete offer details in your prompt (for example, percentages, price values, and campaign context), then test a second tone variant if the first result set feels off-brand.

info

Expected content constraints:

  • Subject lines target 41-64 characters.
  • Pre-headers target 40-130 characters.
  • Emoji usage is limited and spacing is normalized.
  • Final copy may still require manual review before publishing.