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Video marketing for a new app — strategy + the AI video stack

Vertical short video is the highest-leverage channel for a new app in 2026. Here's what to make, and the AI tools that turn a one-person team into a content factory.

If you can only do one marketing channel for a new mobile app, do vertical short video. The algorithm pushes it to non-followers (no audience required), demos are tappable proof, and the AI stack has gotten good enough that one founder can produce 3-5 videos a week solo.

Why vertical short video wins for apps

  • Algorithm-pushed. TikTok, IG Reels, YT Shorts all distribute video to non-followers. A still image or text post mostly reaches your existing audience.
  • Demos convert. Showing a feature in 5 seconds beats describing it in 100 words. Tap-to-install conversion from a demo Reel is typically 2-5× higher than from a text ad.
  • Cheap iteration. Record a feature in 30 seconds. If it bombs, record another. The economics ruin paid ads for the same purpose.

What to make (4 video types that work)

  1. The 5-second demo.Just the feature, no setup. Caption tells the story. Best for the "wow" moments.
  2. The before/after. Old way (a competitor, manual process, spreadsheet) → your app. 7-15 seconds. Strong conversion.
  3. The voice-over tutorial. Talking head OR screen recording with your voice. 30-60 seconds. Best for retention + authority.
  4. The build-in-public clip."I'm adding X. Here's how I'm thinking about it." Founders + the curious eat this up. Authentic = unbeatable on AI-flooded feeds.

The AI video stack in 2026

Honest assessment, no "everything is amazing" framing:

Generative video

  • Sora 2 (OpenAI) — best general-purpose text-to-video. Strong for B-roll, cutaways, generated scenery. Recognizable AI look for character work.
  • Veo 3 (Google) — best for realistic short clips. Strong camera control. Native audio generation is the standout feature.
  • Runway Gen-4 — the editor-friendly option. Good for inpainting / motion-on-static-image. Pro tier is overpriced for indies.
  • Pika 2.0 — fast iteration. Great for quick concept tests, weaker than Veo/Sora for final output.
  • Kling 2.0, Hailuo — strong on physics + motion, less consistent overall. Cheap. Worth trying if Sora is rate-limited.

AI avatars / talking head

  • HeyGen— the "don't want to be on camera" solution. Train a custom avatar in 5 minutes. Lip-sync is good enough that people don't notice unless they're looking for it. Use sparingly — overuse looks fake.
  • Synthesia — enterprise-grade, more expensive. Skip for indie.
  • Captions — combines avatar + captions + B-roll. Closest to one-click vertical video. Quality is middling.

Voice

  • ElevenLabs — best voiceover quality, period. Free tier covers a couple of videos a week. Clone your own voice in 1 minute if you want consistency without recording.
  • PlayHT — alternative with cheaper bulk pricing.

Editing + captions

  • CapCut — free, ubiquitous, what most TikTokers use. The auto-captions are now excellent.
  • Submagic — paid tier (~$15/mo). Best-in-class auto-captions with style presets that match the high-converting TikTok look. Cuts hours of CapCut work.
  • Opus Clip— feed a long video, get short clips auto-cropped + captioned. Useful if you're repurposing podcasts or webinars.
  • Veed.io — browser-based, simpler than CapCut.

Three pipelines you can run today

Pipeline A — The demo Reel (10 min total)

  1. Screen record your app showing one feature (15-30 sec)
  2. Run the video-script-writer skill — give it your feature + ICP, get a hook + 30-sec script
  3. Record voiceover with ElevenLabs (or just read it yourself)
  4. Combine in CapCut, add auto-captions (or pass through Submagic)
  5. Export 9:16, post to IG Reels + TikTok + YT Shorts

Pipeline B — The AI avatar tutorial (15 min total)

  1. Run video-script-writer for a 60-sec tutorial
  2. Paste into HeyGen with your trained avatar
  3. Add screen-recording cutaways at the "feature" moments
  4. Auto-captions in Submagic
  5. Export, post

Pipeline C — Generative B-roll (20 min total)

  1. Record your main footage (talking head or screen)
  2. Identify 3-4 moments that need B-roll. Generate each with Veo 3 or Sora 2 — 3-second clips.
  3. Cut them in as cutaways in CapCut
  4. Caption + export

Prompt formula for Sora / Veo

The "Subject + Action + Setting + Style + Camera + Duration" pattern. Example:

A young product designer (subject) typing on a laptop in a coffee shop (action + setting), warm cinematic lighting, shallow depth of field (style), slow dolly-in (camera), 5 seconds (duration).

Cross-posting + watermarks

  • Strip watermarks before cross-posting. TikTok watermarks on IG Reels = algorithm suppression. Use snaptik or similar.
  • Vertical 9:16 everywhere. 1080×1920. Same file works on TikTok, Reels, Shorts.
  • Cover image / thumbnail matters. Pick a frame that makes sense without sound. People scrolling will see this on your profile grid.