Welcome: Why Custom GPTs Are the New Apps

A marketing director spends 20 minutes every morning pasting the same 500-word prompt into ChatGPT to analyze overnight campaign data. A customer support lead copies their company’s FAQ into every new chat, hoping ChatGPT will answer consistently. A freelance writer starts each session by explaining their tone, audience, and formatting preferences.

All of them are doing it wrong. There’s a better way.

What You’ll Learn

By the end of this lesson, you’ll understand what custom GPTs are, why they matter, and exactly what you’ll build in this course.

Course Objectives:

• Design a custom GPT from concept to published product using the GPT Builder
• Write effective system instructions that control GPT behavior reliably
• Apply knowledge files to give GPTs specialized domain expertise
• Build GPT Actions that connect to external APIs and services
• Evaluate and iterate on GPT performance through systematic testing
• Create a publishing and monetization strategy for the GPT Store

What Is a Custom GPT?

A custom GPT is a tailored version of ChatGPT built for a specific purpose. Think of it like this:

• Regular ChatGPT is a general-purpose assistant. You tell it what to do every time.
• A custom GPT is a specialist. It already knows its role, has access to your documents, and behaves exactly how you configured it.

Every custom GPT has four building blocks:

✅ Quick Check: What are the four building blocks of a custom GPT? (Answer: Instructions, Knowledge, Capabilities, and Actions.)

Who Is Building Custom GPTs?

Custom GPTs have exploded since the GPT Store launched. Here’s what people are building:

For business:

• Internal onboarding assistants that answer new hire questions using company policies
• Sales proposal generators trained on past winning proposals
• Meeting summarizers that follow a specific template
• Data analysts that know your KPI definitions and reporting formats

For personal use:

• Meal planners that know your dietary restrictions and favorite cuisines
• Fitness coaches that remember your workout history
• Study tutors specialized in specific subjects
• Travel planners that match your budget and travel style

For the GPT Store:

• Writing tools (resume builders, email drafters, cover letter generators)
• Productivity tools (project planners, habit trackers)
• Creative tools (story generators, art prompt builders)
• Technical tools (code reviewers, SQL query generators)

What Makes a Good Custom GPT?

Not all GPTs are created equal. The best ones share three qualities:

1. Focused purpose — They do one thing well instead of trying to do everything
2. Clear instructions — They behave consistently because the instructions leave no ambiguity
3. Real value — They save time, improve quality, or enable something users couldn’t do alone

A GPT that tries to be “your all-in-one AI assistant” will underperform a GPT built specifically to “write LinkedIn posts in your brand voice using your company’s case studies.”

How This Course Works

Over 8 lessons, you’ll build a fully functional custom GPT from scratch:

1. Welcome (this lesson) — Why custom GPTs matter
2. GPT Builder — Navigate the creation interface
3. Instructions — Write system prompts that control behavior
4. Knowledge Files — Upload documents for domain expertise
5. Capabilities — Configure tools and conversation design
6. Actions — Connect to external APIs
7. Testing — Debug and iterate until it works perfectly
8. Capstone — Build, publish, and share your GPT

Each lesson includes hands-on exercises. By the end, you’ll have a published GPT ready for users.

What to Expect

You’ll need a ChatGPT Plus, Team, or Enterprise subscription — free-tier users can’t create GPTs. No coding is required for most of the course. The Actions lesson (Lesson 6) covers API configuration, but we walk through it step by step.

Plan to spend about 15 minutes per lesson, plus time for hands-on building. Most students complete the course in one or two sittings.

Key Takeaways

• Custom GPTs package instructions, knowledge, and capabilities into reusable AI tools
• They work for business automation, personal productivity, and GPT Store products
• The best GPTs are focused, well-instructed, and genuinely useful
• You don’t need coding skills — the GPT Builder uses natural language

Up Next

In the next lesson, you’ll open the GPT Builder for the first time and learn every part of the creation interface — from naming your GPT to configuring its capabilities.