Technical Demo Design: Live Coding vs. Pre-Recorded Demos

"Can you demo the product?" sounds simple. But with developer products, demos are high-stakes. Go wrong—code doesn't work, demo is too slow, or you show irrelevant features—and developers check out.

Great technical demos prove value quickly, show real code, and leave developers wanting to try it themselves. Here's how to design and deliver them.

Live Coding vs. Pre-Recorded: The Decision

Live coding:

What it is: Writing code in real-time while demoing.

Pros:

• Authentic, shows real development process
• Can adapt based on questions
• Developers respect "if it breaks, we'll debug together"
• Shows confidence in product

Cons:

• Risky (typos, environment issues, time pressure)
• Slower (typing takes time)
• Hard to control timing
• Stressful for presenter

When to use:

• Small group demos (1-5 people)
• Workshops where audience codes along
• When showing debugging/development workflow
• Experienced presenter comfortable with risk

Pre-recorded demo:

What it is: Screen recording showing product in action, played during presentation.

Pros:

• Polished, no mistakes
• Perfect timing
• Can edit for clarity
• Less stress
• Works even if internet/environment fails

Cons:

• Less authentic feeling
• Can't adapt to questions mid-demo
• Risk of looking like infomercial
• Have to re-record when product changes

When to use:

• Large audience (100+ people)
• Conference talks with strict time limits
• Unreliable internet/environment
• Complex demo with many steps
• Less experienced presenter

Hybrid approach (recommended):

Pre-record demo as backup. Try live. If issues, switch to recording.

"Looks like my environment is having issues. Let me show you the recording while we troubleshoot."

Safety net reduces stress, enables risk-taking.

The 5-Minute Rule

Developers will give you 5 minutes to prove value:

In those 5 minutes:

• Show the problem
• Show your solution working
• Show code
• Prove it's not vaporware

If you don't deliver value in 5 minutes, they tune out.

Example structure:

Minute 0-1: Problem

"When building APIs, authentication is complex. OAuth setup takes days. Here's typical code..."

[Show complex authentication code, 50+ lines]

Minute 1-4: Solution

"With [Product], same authentication in 3 lines:"

const auth = require('product-auth');
auth.protect('/api/*');
// That's it. OAuth, JWT, sessions all handled.

[Show it working - request → authenticated → success]

Minute 4-5: Proof

"This is running live. Let me make a request..."

[curl command → see it work]

[Check logs → see authentication flow]

Value proven. Now they'll watch more.

Demo Structure That Works

Full demo structure (15-30 minutes):

1. Setup (2 minutes)

Who you are + what we're building:

"I'm [Name] from [Company]. Today we're building a real-time notification system. By the end, you'll see messages flow from server to browser in real-time."

Not: Long background on company history, funding, customer logos.

2. Starting point (3 minutes)

Show the before state:

"Here's a typical notification system. Polling every 5 seconds. Inefficient, not real-time, scales poorly."

[Show code + working example]

Establish the problem clearly.

3. Implementation (10-15 minutes)

Build the solution using your product:

Progressive steps:

1. Install and configure
2. Basic implementation
3. Add key feature
4. Show it working
5. Add advanced feature (optional)

Each step: Code → Explain → Results

4. Results (3-5 minutes)

Show it working end-to-end:

"Now let's test. I'll send a notification from here... and it appears instantly here."

[Live demonstration of working product]

Compare to before:

• Before: 5-second delay
• After: Instant
• Code reduced from 200 lines to 15

5. Next steps (2 minutes)

How to try it:

"Everything I showed is in the quickstart: [URL]

You can have this running in 10 minutes.

Code repo: [URL] Docs: [URL]

Questions?"

What to Show (and What to Skip)

Show:

Working code:

Not slides about code. Actual code in editor.

Real examples:

Not foo/bar. Realistic use cases.

Results:

Don't just write code. Show it running. Prove it works.

Error handling:

"What happens when authentication fails? Here's the error..."

[Shows helpful error message]

Performance/scale:

If it's a selling point, show it:

"Let's hit this endpoint 1,000 times/second..."

[Shows it handling load]

Skip:

Company background:

Developers don't care. Get to code.

Slide decks:

Unless absolutely necessary. Code > slides.

Features no one asked about:

"Our product also does X, Y, Z..." when audience needed A and B.

Focus on what matters to this audience.

Long explanations:

Show first, explain briefly after.

Perfect code:

Don't try to show perfect production code. Show what works.

Environment Setup for Demos

Prepare demo environment:

Isolated environment:

Don't demo in production or your main dev environment.

Separate:

• Demo account/API keys
• Demo database with sample data
• Demo deployment

Pre-configured:

Set up before demo starts:

• Dependencies installed
• Code scaffolding ready
• Database seeded with data
• Authentication configured

Not: "Let me install Node.js... this will take 5 minutes."

Version control:

Demo code in Git:

• Can revert if you mess up
• Can share repo after demo
• Shows professional workflow

Checkpoints:

For longer demos, have code at different stages:

/demo-step-1-basic
/demo-step-2-with-auth
/demo-step-3-production-ready

If you get behind, jump to next checkpoint.

Screen setup:

Resolution: 1920x1080, mirrors well to projectors

Font size: Huge (22-28px minimum)

Theme: High contrast

• Light: GitHub Light
• Dark: Dracula, One Dark Pro

Hide clutter:

• Close unnecessary apps
• Hide bookmarks bar
• Minimize file tree
• Do Not Disturb mode (no notifications)

Two monitors:

• Primary: Code/terminal (what audience sees)
• Secondary: Notes, timer, chat/questions

Internet backup:

Demo requires internet?

Have backup:

• Mobile hotspot ready
• Pre-recorded video if internet fails
• Local fallback (if possible)

Handling Things Going Wrong

Mistakes will happen. How you handle them matters:

Typo in code:

Don't: Panic, restart, apologize profusely.

Do: "Oops, typo. Let me fix that..." [fixes, moves on]

Shows real development process.

Code doesn't work:

Don't: "Umm, this should work... I don't know why..."

Do: "Interesting. Let me check... [brief debugging]. Ah, missing semicolon. There we go."

Shows debugging skills, confidence.

If it takes >2 minutes to debug:

"This is taking longer than expected. Let me show you the recording while I troubleshoot offline."

Environment issue:

Have backup:

"My Docker container isn't starting. Good thing I have this working in CodeSandbox..."

[Switches to cloud IDE]

Complete failure:

Worst case:

"My environment is completely broken. Here's the pre-recorded demo. I'll have the working code in the chat and can debug specific questions after."

Acknowledge, pivot, keep value delivery going.

Developers respect graceful failure recovery more than perfect demos.

Interactive Demos vs. Presentation Demos

Presentation demo (1 to many):

Format:

• You show, they watch
• Questions at end (or specific breakpoints)
• More scripted

When: Conference talks, webinars, large groups

Interactive demo (1 on 1 or small group):

Format:

• Collaborative exploration
• "What would you like to see?"
• "How would you integrate this?"
• Adapt based on their needs

When: Sales demos, customer calls, workshops

Interactive requires:

• Deep product knowledge (can't script it)
• Ability to code live under pressure
• Understanding of customer use case

Presentation requires:

• Tight scripting
• Pacing control
• Repeatability

Different skills. Practice both.

Recording Great Demo Videos

If pre-recording:

Script loosely:

Bullet points, not word-for-word.

Natural delivery beats perfect script.

Record in segments:

Don't try to record 20-minute demo in one take.

Record in 2-3 minute segments:

1. Introduction
2. Setup
3. Implementation step 1
4. Implementation step 2
5. Results
6. Conclusion

Edit together. Much easier than perfect 20-minute take.

Edit for pace:

Cut:

• Long pauses
• Typing delays (speed up or cut)
• Dead air
• Mistakes

Keep:

• Explanations
• Working code
• Results

Add text overlays:

For key points:

• Commands to type
• URLs to visit
• Key concepts

Background music?

For marketing videos: Maybe (very subtle).

For technical demos: Usually no. Keep focus on content.

Practice Makes Perfect

First demo will be rough. 10th will be good. 50th will be great.

Practice routine:

Week 1: Record yourself demoing. Watch it.

Notice:

• Where you stumble
• What's unclear
• Timing issues

Week 2: Demo to colleague or friend. Get feedback.

Week 3: Demo to small internal group. Practice Q&A.

Week 4: Demo to friendly customer or beta user.

Week 5: Ready for real demo.

Keep practicing:

Even experienced presenters rehearse before big demos.

Demo Formats

5-minute elevator demo:

For: Quick meetings, chance encounters, cold outreach

Structure:

• 1 min: Problem
• 3 min: Solution (code + working example)
• 1 min: Next steps

15-minute feature demo:

For: Customer calls, partner meetings

Structure:

• 2 min: Context
• 10 min: Feature deep-dive with code
• 3 min: Q&A

30-minute product demo:

For: Evaluation meetings, webinars

Structure:

• 3 min: Problem and context
• 20 min: Multi-feature demo with implementation
• 7 min: Q&A and next steps

90-minute workshop:

For: Training, hands-on sessions

Structure:

• 10 min: Overview
• 60 min: Hands-on coding (audience follows along)
• 20 min: Advanced topics and Q&A

Measuring Demo Effectiveness

Track:

Engagement:

• Questions asked
• Request for follow-up
• Trial signups after demo

Feedback:

• Post-demo survey
• "Was this helpful?"
• What would improve it?

Conversion:

• Demo → trial rate
• Demo → meeting rate
• Demo → purchase rate

Iterate:

What demos convert best? Do more of those.

What demos fall flat? Fix or drop them.

Common Demo Mistakes

Mistake 1: Too much setup

15 minutes of explanation before any code.

Fix: Code in first 2 minutes.

Mistake 2: Showing everything

"Our product also does X, Y, Z..." when customer needed A.

Fix: Show what matters to this audience.

Mistake 3: No working proof

Code shown but never run.

Fix: Always show it working.

Mistake 4: Reading from script

Sounds robotic, unnatural.

Fix: Bullet points, natural delivery.

Mistake 5: Ignoring questions

"I'll get to that later..." then forget.

Fix: Note questions, address them specifically.

Getting Started

Week 1: Outline demo flow. What will you show?

Week 2: Set up demo environment. Test it works.

Week 3: Record yourself demoing. Watch and critique.

Week 4: Demo to friendly audience. Get feedback.

Week 5: Refine based on feedback. Ready for real demos.

Ongoing: Every demo is practice. Keep improving.

Great demos make complex products feel simple, show real value quickly, and leave developers wanting to try it themselves.

Show working code. Prove it's not vaporware. Make them believe in 5 minutes.

That's a winning technical demo.