Uploaded April 2025 | Updated September 2026, 1 week ago
Join me, Billy Howell, and Nic Conley as we vibe code an "Invoice Nudger" SaaS App that helps freelancers automatically follow up on unpaid invoices. Using Replit's AI agent and Resend email service, we create a functional prototype in under an hour that can send customized reminder emails. We also discusses effective marketing strategies for SaaS products, including LinkedIn short-form videos, cold email campaigns, and targeted outreach.
Timestamps:
00:00 - Intro
04:41 - Why Vibe Code
07:43 - Strategizing how to approach MVP
10:28 - Starting the app development in Replit
27:24 - Marketing strategy discussion
46:55 - Testing and debugging the app
59:09 - App Works!
Key points
• We build an automated invoice follow-up tool using Replit and Resend email service
• We demonstrate how to use AI to code a functional web app with minimal technical knowledge
• The app automatically sends increasingly assertive emails to clients with unpaid invoices
• We discuss multiple marketing strategies for launching SaaS products
1) The Problem They're Solving
Freelancers and agencies struggle with getting paid on time.
It's rarely malicious - clients just forget!
The solution: Invoice Nudger - a tool that automatically sends increasingly assertive (but professional) follow-up emails until payment is received.
No awkwardness. Just results.
2) Building the MVP in Under an Hour
They used just TWO tools to create a functioning app:
• Replit - AI coding assistant to build the app
• Resend - Email API for sending the reminders
The process:
1. Create a PRD with ChatGPT
2. Feed it to Replit's AI agent
3. Set up email sending with Resend
4. Test the functionality
ZERO coding knowledge required!
3) Key Features of the MVP
The first version focused on core functionality:
• Dashboard showing overdue invoices
• Email templates with varying levels of assertiveness
• Manual "send reminder" button
• Automated follow-up scheduling
Future features could include lawyer letters as premium upsells!
4) Marketing Strategies That WORK
Nic shared 4 awesome marketing approaches:
A) Cold Email Campaign
- Get 10k agency emails from Upwork ($200)
- Use SmartLeads/Instantly to warm up domains
- Test different subject lines
- CTA: "No need to talk to anyone, try it free"
B) TikTok/Instagram Playbook
- Create 4 accounts on each platform
- Target freelancer niche
- Use slideshow format: "5 tools that saved my agency"
C) LinkedIn Short-Form Video
- Post daily videos for 14 days
- Use hooks like "This AI agent collects money without breaking kneecaps"
- Share dashboard screenshots
- Greg called this "fishing with dynamite" right now
D) Hand-to-Hand Combat
- Target 50-100 ideal users
- Comment on their posts
- Enter their orbit before pitching
- Build relationships first
5) The Power of Video Marketing
They discussed Farza’s viral launch of FreeWrite:
His simple, beautiful promo video got 1.5M views and hundreds of downloads per hour.
The lesson: Even in crowded markets, great video content + clean design can break through.
For Invoice Nudger, they suggested mob movie-themed marketing!
6) The Big Takeaway
The most MIND-BLOWING part? They went from idea to functioning app with custom domain in ONE HOUR.
As Billy said: "This is like a heist!"
The barrier to entry for building SaaS has NEVER been lower.
What are you waiting for?
If you're building in public, Billy's advice: "Make 50 apps. Don't get stuck on one. Try making each idea 3 different ways."
The world is crazy right now - you can build AND market for free.
Notable Quotes:
"This is a heist, guys. I can't believe we did this. Wow." - Billy Howell after successfully implementing the email functionality
"If you're not having fun building startups, then you're doing it wrong." - Greg Isenberg
LCA helps Fortune 500s and fast-growing startups build their future - from Warner Music to Fortnite to Dropbox. We turn 'what if' into reality with AI, apps, and next-gen products https://latecheckout.agency/
BoringAds — ads agency that will build you profitable ad campaigns boringads.com
BoringMarketing — SEO agency and tools to get your organic customers boringmarketing.com
Startup Empire — a membership for builders who want to build cash-flowing businesses startupempire.co
FIND ME ON SOCIAL
X/Twitter: twitter.com/gregisenberg
Instagram: instagram.com/gregisenberg
LinkedIn: linkedin.com/in/gisenberg
FIND BILLY ON SOCIAL
X/Twitter: https://x.com/billyjhowell
Youtube: youtube.com/@billyjhowell
FIND Nic ON SOCIAL
X/Twitter: https://x.com/niconley
Youtube: youtube.com/@niconley/featured
Join me, Billy Howell, and Nic Conley as we vibe code an "Invoice Nudger" SaaS App that helps freelancers automatically follow up on unpaid invoices. Using Replit's AI agent and Resend email service, we create a functional prototype in under an hour that can send customized reminder emails. We also discusses effective marketing strategies for SaaS products, including LinkedIn short-form videos, cold email campaigns, and targeted outreach.
Timestamps:
00:00 - Intro
04:41 - Why Vibe Code
07:43 - Strategizing how to approach MVP
10:28 - Starting the app development in Replit
27:24 - Marketing strategy discussion
46:55 - Testing and debugging the app
59:09 - App Works!
Key points
• We build an automated invoice follow-up tool using Replit and Resend email service
• We demonstrate how to use AI to code a functional web app with minimal technical knowledge
• The app automatically sends increasingly assertive emails to clients with unpaid invoices
• We discuss multiple marketing strategies for launching SaaS products
1) The Problem They're Solving
Freelancers and agencies struggle with getting paid on time.
It's rarely malicious - clients just forget!
The solution: Invoice Nudger - a tool that automatically sends increasingly assertive (but professional) follow-up emails until payment is received.
No awkwardness. Just results.
2) Building the MVP in Under an Hour
They used just TWO tools to create a functioning app:
• Replit - AI coding assistant to build the app
• Resend - Email API for sending the reminders
The process:
1. Create a PRD with ChatGPT
2. Feed it to Replit's AI agent
3. Set up email sending with Resend
4. Test the functionality
ZERO coding knowledge required!
3) Key Features of the MVP
The first version focused on core functionality:
• Dashboard showing overdue invoices
• Email templates with varying levels of assertiveness
• Manual "send reminder" button
• Automated follow-up scheduling
Future features could include lawyer letters as premium upsells!
4) Marketing Strategies That WORK
Nic shared 4 awesome marketing approaches:
A) Cold Email Campaign
- Get 10k agency emails from Upwork ($200)
- Use SmartLeads/Instantly to warm up domains
- Test different subject lines
- CTA: "No need to talk to anyone, try it free"
B) TikTok/Instagram Playbook
- Create 4 accounts on each platform
- Target freelancer niche
- Use slideshow format: "5 tools that saved my agency"
C) LinkedIn Short-Form Video
- Post daily videos for 14 days
- Use hooks like "This AI agent collects money without breaking kneecaps"
- Share dashboard screenshots
- Greg called this "fishing with dynamite" right now
D) Hand-to-Hand Combat
- Target 50-100 ideal users
- Comment on their posts
- Enter their orbit before pitching
- Build relationships first
5) The Power of Video Marketing
They discussed Farza’s viral launch of FreeWrite:
His simple, beautiful promo video got 1.5M views and hundreds of downloads per hour.
The lesson: Even in crowded markets, great video content + clean design can break through.
For Invoice Nudger, they suggested mob movie-themed marketing!
6) The Big Takeaway
The most MIND-BLOWING part? They went from idea to functioning app with custom domain in ONE HOUR.
As Billy said: "This is like a heist!"
The barrier to entry for building SaaS has NEVER been lower.
What are you waiting for?
If you're building in public, Billy's advice: "Make 50 apps. Don't get stuck on one. Try making each idea 3 different ways."
The world is crazy right now - you can build AND market for free.
Notable Quotes:
"This is a heist, guys. I can't believe we did this. Wow." - Billy Howell after successfully implementing the email functionality
"If you're not having fun building startups, then you're doing it wrong." - Greg Isenberg
LCA helps Fortune 500s and fast-growing startups build their future - from Warner Music to Fortnite to Dropbox. We turn 'what if' into reality with AI, apps, and next-gen products https://latecheckout.agency/
BoringAds — ads agency that will build you profitable ad campaigns boringads.com
BoringMarketing — SEO agency and tools to get your organic customers boringmarketing.com
Startup Empire — a membership for builders who want to build cash-flowing businesses startupempire.co
FIND ME ON SOCIAL
X/Twitter: twitter.com/gregisenberg
Instagram: instagram.com/gregisenberg
LinkedIn: linkedin.com/in/gisenberg
FIND BILLY ON SOCIAL
X/Twitter: https://x.com/billyjhowell
Youtube: youtube.com/@billyjhowell
FIND Nic ON SOCIAL
X/Twitter: https://x.com/niconley
Youtube: youtube.com/@niconley/featured
