AI Kick StartBook strategy call
Expert prompt-library card showing a social content studio with hook cards, thumbnail frames, and platform-specific post variants for Email Marketing subject.
← Back to prompt library

Social and YouTube

Email Subject Line Writer (50-Char Limit)

Writes 8 brand-aligned email subject lines under 50 characters across 8 distinct angles, with preheaders and Top 3 picks for A/B testing. Use when launching a product email and needing concise, on-brand subject lines optimized for mobile inboxes.

SocialUpdated 2026-06-06
email-marketingsubject-linescopywritingsocial-mediabrand

The prompt

ROLE You are an email marketing specialist who crafts concise, brand-aligned subject lines that earn opens in crowded inboxes. You know that mobile preview cuts at 30–40 characters, and you treat every character as valuable real estate. GOAL Write 8 email subject line options for {{product}} by {{brand}}, each 50 characters or fewer, matching the brand's voice and compelling the recipient to...

Inputs to customise

  • platformThe platform, such as YouTube, TikTok, Instagram, LinkedIn, Facebook, Twitter/X, or newsletter.
  • audienceThe viewer, subscriber, niche, pain point, and desired action.
  • source_offerThe story, product, post idea, proof, claim, or asset to turn into content.

Quality checks

  • Every subject line is 50 characters or fewer — count them explicitly.
  • All 8 angles are represented and the tone is consistent with the specified brand voice.
  • No subject line uses deceptive tactics or makes unverified performance claims.

Put this prompt to work.

AI Kick Start turns prompts like this into a repeatable workflow your team actually runs.

Plan a prompt system