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A good demo can make or break your startup. It captivates investors, attracts customers, and generates buzz. Here’s how to build demos that actually work.

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✅ Good Demo vs ❌ Bad Demo

✅ Good Demo: Tells a Story
  • Has a clear main character (your user) with a problem.
  • The product solves it and saves the day.
  • Every step is necessary to move from problem ➝ solution.
  • Leaves the audience satisfied and inspired.
❌ Bad Demo: Gives a Tour
  • Moves exhaustively from feature to feature.
  • Lacks clear narrative or user perspective.
  • Focuses on irrelevant or generic features.
  • Leaves the audience confused and bored.
✅ Good Demo: Has a Magic Moment
  • Surprises the audience with power + elegance.
  • Creates a moment people talk about.
  • Drives conviction to buy.
❌ Bad Demo: Forgettable
  • Reasonable but not exciting.
  • Doesn’t leave a lasting impression.
✅ Good Demo: Believable
  • Assumes audience is skeptical.
  • Explains how things work with just enough detail.
  • Impresses because it feels real and pulled off well.
❌ Bad Demo: Feels Fake
  • Vague, hand-wavy, or overhyped.
  • Glosses over how it actually works.
  • Leaves the audience skeptical.
✅ Good Demo: Tailored to the Audience
  • Uses your prospect’s logo, language, and specific problems.
  • Feels personalized and thoughtful.
  • Connects deeply with the audience’s world.
❌ Bad Demo: Generic
  • Filled with acronyms and buzzwords.
  • Uses placeholder assets and dummy data.
  • Looks like every other demo.
✅ Good Demo: Engaging & Interactive
  • Presenter is animated and excited.
  • Checks in with audience frequently.
  • Encourages questions and discussion.
❌ Bad Demo: Dry & One-Sided
  • Presenter lacks energy.
  • Pushes forward regardless of audience engagement.
✅ Good Demo: Ready Instantly
  • Can be spun up in seconds.
  • Easy to repeat across your team or customers.
  • Minimal setup and friction.
❌ Bad Demo: Fragile & Tedious
  • Requires dev setup or local environment.
  • Only works on your laptop.
  • Often breaks mid-way.

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🛠️ How to Deliver a Great Demo

  • Explain the main character — clarify the role you’re playing and the problem you’re solving.
  • Practice end-to-end — record yourself (e.g. with Tella.tv) and refine.
  • Rehearse with others — teammates, YC partners, or early users.
  • Automate prep — use realistic, tailored data for different personas/verticals.
  • Avoid lorem ipsum — fake text breaks immersion. Use realistic content.
  • Use a good mic — audio quality matters, especially over Zoom.
  • Jokes are fine, but only if they don’t sacrifice clarity or realism.
  • Show, then tell — demo the magic first, explain it after.
🧠 Remember: A great demo isn’t just a walkthrough — it’s a story, a connection, and a conversion engine.
credit to yc: https://bookface.ycombinator.com/knowledge/HJ-building-good-demos