Thomas Blakeley, writing on InkTip, explains Writing for Verticals: How to Break Into the New Format Producers Want.

He defines these micro-dramas thusly:

“Format: 9:16 screen (like TikTok or Instagram Reels).
Episodes: 2–3 minutes each, built on intrigue and cliffhangers.
Season: Anywhere from 20 to 100+ episodes, depending on length.
Style: Hook-driven, character-focused, and designed to keep you watching one bite-size piece after another.”

He then goes into why producers want verticals, how to write a vertical and the genres producers want right now.

He concludes with this checklist:

1. “Is your total story length 30, 45, 60, or 90 minutes broken into 2–3 minute episodes?
2. Does each episode end on a cliffhanger or emotional punch?
3. Can each mini-arc satisfy the viewer while feeding the bigger story?
4. Are you keeping it tight (faces, hands, one or two characters at a time)?
5. Is your premise simple enough to repeat across 20+ short episodes?”

My take: I believe that movies and TV should be horizontal, not vertical.