How to Use AI in Your Newsletter Writing Workflow (ft. Kortex)

Let’s be real — writing newsletters can feel like staring into the abyss of a blank Google Doc. Whether you’re a seasoned creator or just starting out, the process can be frustrating, time-consuming, and downright uninspiring.

That’s why we were pumped to sit down with Joey Justice, co-founder of Kortex, who’s not only built a killer writing app but has also written over 600 viral Twitter threads as a ghostwriter.

In this post, we’re pulling back the curtain on his exact process, AI prompts included, so you can finally write newsletters people actually want to read (and maybe even grow your audience along the way).

Table of Contents

• Key Timestamps

• Top 6 Takeaways and Next Steps

• Key Resources & Tools Mentioned

• Closing Note

Key Timestamps

Getting started 👇

00:00 - What we'll be covering

01:57 - Understanding Kortex: Features and capabilities

Tools for your creative process 🧠

04:55 - AI prompts for writing assistance

12:09 - Tips for social media growth

20:41 - Writing the perfect prompt

25:17 - Insights from Dan Koe

29:00 - Engagement metrics: Tracking what works

32:42 - Building an outline for your newsletter with AI

Q&A 🙋🏻‍♂️

39:24 - Making your content stand out

42:33 - The ideal posting cadence

44:15 - Creators to follow

Top 6 Takeaways and Next Steps

1. Capture, Curate, Connect, Create

Next Step: Set up a system (like Kortex or Notion) where you can store inspiration, notes, and resources. The more organized your “second brain,” the easier writing becomes.

2. Start with Your “Big Idea”

Next Step: Before you write, spend 5 minutes identifying the core message you want to share. Who’s your audience? What problem are you solving? Write this down in every draft.

3. Use AI to Break Through Writer’s Block

Next Step: Use Joey’s newsletter prompts in ChatGPT, Claude, or Kortex to brainstorm topics and create outlines in minutes.

4. Write to Your Former Self

Next Step: Make a list of struggles you’ve overcome and lessons you’ve learned. This is your content goldmine — your audience is probably dealing with the same stuff.

5. Repurpose Like a Pro

Next Step: Turn your newsletter into a Twitter thread (listicle style works best), a LinkedIn post, and an Instagram carousel. One idea = multiple platforms.

6. Track What Works — Then Do More of That

Next Step: Use Twitter’s Advanced Search or tools like Typefully to find your top-performing posts. Save them in a “greatest hits” folder to study what worked and repeat the formula.

Key Resources & Tools Mentioned

• Kortex

• Readwise

• ChatGPT

• Claude

• Typefully

• Twitter Advanced Search

• Dan Koe’s YouTube Channel

Closing Note

Joey’s message is clear — in a world where anyone can write with AI, quality and personality win. Tools like Kortex and ChatGPT can make your process faster (Joey’s prompts alone can save you hours), but the real magic happens when you write from experience, add your unique spin, and aren’t afraid to have a strong opinion.

If you want to write newsletters that actually matter — and grow your audience along the way — start by writing to your former self. Capture the lessons you wish you had years ago, package them with some personality, and share them consistently across platforms.

And if you want to go even deeper into this process, check out Joey Justice on X or dive into Kortex yourself to see how a second brain for creators can transform your writing workflow.

With beehiiv, you can build a community that you own as a creator, and the best part is you can start for free!