AI email marketing, for entrepreneurs, creators and founders.

By the time you've rewritten ChatGPT's draft, GravityFlo has scored, sent and reported back.

Nat & Drew video — placeholder

The AI-native email marketing platform that learns your voice from your past writing, writes every new email in your tone, and tells you how each one's likely to land before you press send. AI that amplifies your voice. Never replaces it.

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Sit with WillBelleVie HealthRadiovilleThe Reflexology PlaceStress MonkeealmedaAndrea Galerproud.Scale for ImpactNick SantonastassoHumanity's Team

For entrepreneurs, creators and founders with 500 to 5,000 subscribers.

For the people writing their own emails.

For the ones who tried AI and binned the draft.

It's Tuesday morning. The coffee's gone cold. You've started three emails. Deleted all three. Your list is waiting. And the day is swooshing by.

Sound familiar?

  • Every month, your ESP charges you for features you've never used. CRM, popups, landing pages, sales pipelines. The bigger your list grows, the more you pay for things you don't need.

  • You sent the email. Half your subscribers might never see it. Gmail might send you to Promotions. Outlook might break it in dark mode. You can't fix what you can't see.

  • Writing was never your thing. So you turned to AI for help. The output came back clean, competent, flat. You tweaked it. Re-prompted. An hour gone. Still not an email that sounds like you.

  • You have 2,000 subscribers. They all behave differently in their inbox. Open at different times. Click on different things. But the same email goes out to all of them, at the same hour, in the same shape.

  • You hit send. There's a small flinch. You refresh the dashboard at lunch. The open rate is lower than last week. And the doubt starts whispering: are they still listening?

Here's where this stops.

You write the brief. ChatGPT writes the email. You check, fix, second-guess, send. GravityFlo doesn't work like that. We take care of the prompts, the email creation (with your unique input) and optimise the delivery.

What's inside

Built for the people who actually care about their list.

Email is still the most direct line you have to the people who chose you. Know-like-trust lives in the inbox. And in a world where AI is flooding everyone with the same beige draft, the opportunity to sound like you, stand out, and earn that trust has never been bigger.

We've been entrepreneurs, founders, freelancers for most of our adult lives. We know what it takes to grow a business one email at a time. The pressure. The doubt. The wins. The “is anyone reading this?” moments. So we built GravityFlo. The tool we wished we had at the start of our journey. The complete email marketing platform that puts your voice, your audience, and your mission at the centre.

Our AI amplifies your voice, doesn't flatten it. The frameworks of the world's best marketers shape every send. The technical work happens in the back end. You save the hours, skip the second-guessing, and stop trying to learn copywriting on the fly.

Here's what's inside.

Silent demo — placeholder

  • An email platform that just does emails.

    Other platforms have FOMO. We're proud to miss out. No CRM. No course builder. No website builder. No SMS dialer. No customer service inbox. Just the things that make email work: writing, sending, scoring, deliverability. Priced for what you actually use.

  • Land in the inbox. Your email looks right when it gets there.

    DKIM, SPF, DMARC, custom domain, sender warmup. Dark-mode rendering in Outlook checked and fixed before you send. Bounce and complaint handling baked in. All built into the back end. You don't even have to think about it.

  • Write emails that sound like you.

    Start from a blank page, or paste in your own, or pick from one of the eight templates built for the emails every business needs. GravityFlo's Brand Signature learns your voice from your past writing. Then answer a few quick questions in the Brief Composer. Save your briefs for next time. Every email comes out in your tone. No more bouncing between AI tools and your ESP. No more tweaking. No more re-prompting. No more “this doesn't sound like me.”

  • Send each subscriber the email they'll actually open.

    GravityFlo personalises by behaviour. The more it learns about your subscribers, the more it fine-tunes how you write to them. Different segments behave differently. Some always open. Some never click. Some only buy when you launch. Over time, GravityFlo tailors your emails to each segment, and sends them at the times each segment actually opens, wherever in the world they are. Every send tuned to the segment, not the broadcast.

  • Know before you send.

    Every email gets a Flo Score in real time. Subject line strength. Readability. Likely engagement. You see how it'll land before your subscribers do. So you send with confidence, not crossed fingers.

Rooted in the timeless principles of marketing, copywriting and influence. The science Cialdini wrote books about, the craft Belgray makes personality-driven, the formulas Schwartz wrote the rulebook on. None of which you have to study to get the benefit of.

Join the waitlist

To save your seat at the live demo workshop. See GravityFlo in action. Decide if it's for you.

Why voice matters

Everyone has AI now. No one has your voice.

Email is the channel that carries your voice furthest.

It still drives more revenue per dollar than any other marketing channel. Paid search. Social. Display. All of them.

In a 2026 inbox flooded with AI drafts, it's the emails that sound like the person writing them that subscribers can't wait to read.

The opportunity has never been bigger. The cost of getting it wrong has never been higher.

$36 per $1

The return on every dollar spent on email in 2026. Paid search returns $2. Display returns $1.35. Email is the highest ROI channel in marketing.

Source: Litmus / DMA / Constant Contact, 2026

+41%

The revenue lift from full-stack AI email marketing over manual campaigns.

Source: Salesforce, 2026

6×

The transaction-rate lift on personalised emails over generic ones. What happens when the right message lands with the right person at the right time.

Source: Experian

“Your email list is your most valuable asset. It's the foundation of your business.”
— Amy Porterfield

Which is why we built GravityFlo.

A husband and wife duo. Nat and Drew Milligan.

Portrait of Nat Milligan

Strategist · Copywriter · Voice keeper

Nat Milligan.

Twenty years in sales and marketing. Thirteen of those years writing copy for a living. Years inside award-winning advertising agencies and top-tier marketing firms, leading launches, writing campaigns, building funnels for six to nine figure businesses in personal development and wellness. Founder of The Copy Rebel.

Nat watched AI land in the writing world from the inside. The creators she’d spent years coaching into finding their brand voice started to sound like the same bland newsletter. And the friction grew. People wanting to sound authentic, leaning on AI tools that made them generic. The harder they tried, the more their unique copy style disappeared.

She’s also spent years working inside all the big boy ESPs. They all chase the same trap. Bolting on CRMs, course builders, popups, sales pipelines. Stacking bells and whistles until email itself isn’t the point anymore. Even though, in her opinion, email should be at the heart of the marketing process. Because it still has, to this day, the highest ROI compared to other channels.

GravityFlo is her chance to prove it. An email marketing platform with email at the centre. AI-native from its conception. Not bolted on after. The right tool, at the right time, for people who feel something is missing in their email marketing. Sending with crossed fingers. Never quite seeing the results they’re working so hard to achieve. This is the gap. The one GravityFlo was built to fill.

Portrait of Drew Milligan

Founder · Builder · Simplifier

Drew Milligan.

Drew is in love with technology. Obsessed with automation. Allergic to bloat. Always hunting for the simpler way through. He’s dyslexic, so he looks for the shortcuts when everyone else makes it complicated. Ridiculously good at finding the fastest path between an idea and the working thing.

He’s not a natural musician. He taught himself music production through technology. Built a music career off the back of it. Thirty plus years in the game. He’s not a natural coder. He taught himself by vibe coding his way into it. As a teenager, he watched someone build a recording studio… Then built one himself from scratch.

That’s the brain that built GravityFlo. Same approach he took to music. Brief the piece into existence, then refine. (Which is also where the Brief Composer got its name. When you get inside, you’ll know what we’re talking about. [Wink.])

He’s spent years watching Nat work inside the big-box email platforms. Watched her wrestle the bloat. Hunt for the simple version of features that should never have been complicated. So when he set out to build GravityFlo, he knew exactly how it had to feel. Because he’d watched what the alternative looks like.

Drew leads the build. Platform, AI, design, and the engineering that makes email land… in your subscribers’ inboxes at the right time.

PS.

Drew brings the science. Nat brings the art. Most of the time. Sometimes it flips. Sometimes we argue. Hey, we\u2019re husband and wife co-founders. It happens. There\u2019s no one else we\u2019d rather be squabbling over words on a page with at 2am.

Word of mouth.

GravityFlo is fresh out the gate. Nat\u2019s been around the block more times than she cares to remember. Here\u2019s what some of the people she\u2019s worked with have to say.

She’s an excellent copywriter with real craft. Natalie can go deep into messaging, structure, and nuance, and she takes pride in producing work that’s thoughtful and well-executed. Beyond her skills, Natalie is a fantastic person to work with. She’s supportive, dependable, and brings a calm, strong presence in fast-moving environments. If you’re considering working with Natalie, I strongly encourage you to give it a go. I’m confident you’ll never regret it.

Alessio Pieroni

Founder, Scale for Impact & former CMO at Mindvalley

Nat was my ninja in the sense of copywriting — taking my words, my work, all the things that I do for people all around the world and turning them into magic. Whether that’s my captions, my emails, my sequences, my funnels. She has been one of the most incredible people to work with on making my words matter at a deeper level. Someone who is deeply, deeply present, incredibly heart-centred and takes massive pride in her work. If anyone is on the fence to work with Nat in whatever capacity, please walk the path — because there’s massive transformation on the other side of that decision.

Nick Santonastasso

Global Keynote Speaker, Entrepreneur & Transformational Coach

A wall of voices

\u201CAn investment I wish I’d made years ago. Nat gave me clarity around my ideal customer and brand voice I didn’t know I was missing.\u201D

Scherise

Podcaster & Mindful Manifestation Mentor

\u201CNatalie is a powerhouse. Energy, love, expertise. She got me clear on my business and helped me dream bigger.\u201D

Kate

Embodied Psychotherapist

\u201CI got my website live and my email automation running. Stoked.\u201D

Sarah

Online retailer & wellness coach

\u201CShe doesn’t just teach you how to write copy. She brings out the best in you. My creativity is out of the cage and not going back.\u201D

Tracey

Copy Rebel graduate

\u201CNat knows her stuff. Clear direction, loads of motivation, ideas that are spot on. You’ll be tickled pink with the final product.\u201D

Alicia

Health & Wellness Entrepreneur

\u201CWe jumped straight in. No beating around the bush. She came prepared. Genuinely positive, enthusiastic, contagious. Skill, knowledge, experience. All there.\u201D

Andrew

Cabaret Performer

\u201CShe got me from the very first moment. Holistic, tailor-made, never one-size-fits-all. Reaching out to Nat was the best decision I made.\u201D

Milena

Psychotherapist & Integrated Life Coach

\u201CIf you’re on the fence, just do it. More than a course. A journey to spread your wings and fly.\u201D

Claire

Copy Rebel graduate

\u201CThe next generation of copywriters needs a mentor passionate about the craft. Nat is the guiding light.\u201D

Grace

Copy Rebel graduate

\u201CEverything you need. Nat listened, supported every step. She genuinely cares.\u201D

Nicole

Copy Rebel graduate

Coming from another platform?

Swipe to see the full comparison.

FeatureGravityFloKitFlodeskBeehiivMailchimpActiveCampaignKlaviyo
Brand Signature AI
Learns your voice from past writing
PartialPartialPartialPartialPartial
Flo Score before send
Subject line, readability, predicted engagement
PartialPartialPartial
Per-subscriber send-time intelligence
PartialPartial
DMARC / SPF / DKIM auto-handling
ManualManualPartialManualPartialPartial
Outlook dark-mode preview
Bot-click filtering
PartialPartialPartial
Just email
No CRM, popups, landing builder, journey maze
PartialPartialPartialPartial
Price at 2,500 subs
Per month
$29~$49$25~$49$60~$70~$65
Founding member lifetime price-lock

Coming from one of the big boys?

HubSpot, GoHighLevel, Kajabi and Keap (formerly InfusionSoft) are different animals. They do everything, including email. We do email properly only. [Wink] If you want to keep them for the rest of your stack and bring just the email side over to us, drop us a line. We\u2019ll handle the move.

Things you might be wondering about.

Is GravityFlo actually built, or am I joining a waitlist for an idea?

It’s built. We’re in alpha phase right now. The features described on this page are live, tested, and being used by the alpha cohort. The reason there’s a waitlist is because we’re rolling out access in cohorts, not because the product doesn’t exist.

The live demo will show you GravityFlo in action. When you join us live, there will be no empty promises. No examples of an idea. No mock-ups of a concept. You’ll see how it sends, how it scores, how it learns your voice. In real time.

Is my list size right for this?

GravityFlo is opening in two phases.

Phase 1 (right now): the first 100 founding members lock in $29 a month, for life. For entrepreneurs, creators, and founders with up to 2,500 subscribers on their list. We’re keeping this first cohort small on purpose. The back end gets tested. We iron out any kinks. Then we open up to bigger lists.

Phase 2 (once Phase 1 is settled): doors open to lists between 2,500 and 5,000 subscribers. Register your interest using the link below to be first in line when doors open.

If you’re smaller (between 0 and 500 subs), you’ll likely get more out of starting on a free platform first. Get your email marketing wheels in motion. Build your list. Then come back to us when you’re ready for what we do best.

If you’re bigger (over 5,000 subs), you’re not forgotten. We’re building towards lists at your scale. Drop us a line and let’s book a quick call. We can talk through options like a phased onboarding, or bringing a segment of your list across first.

Will GravityFlo actually sound like me, or just sound like AI?

It will sound like you. That’s the whole point.

Our Brand Signature feature reads your past emails. You show it 3 to 5 examples to start, and it learns from every send after. Sentence rhythm. Word choice. Length. The fingerprints that make your writing yours. Every new email comes out in your tone, not the AI’s.

The whole platform is built on the promise: AI amplifies your voice. Never replaces it.

Why use GravityFlo when I can just use ChatGPT or Claude and copy-paste into my current ESP?

ChatGPT and Claude are brilliant tools. We use them. But AI generates the average of every email it’s ever read, and it’s very much limited by the quality of the prompts it gets. That’s why everyone’s emails sound similar now.

Here’s where GravityFlo is different.

We bring 20 years of marketing experience and 13+ years in copywriting, working alongside some of the best influencer marketers on the planet, baked in. The frameworks, books, research and intel of the best marketers, salespeople, copywriters and launch strategists are encoded into every template you use and every email you write.

Our Brand Signature learns your voice. Our Brief Composer does the prompt engineering for you, drawing on those frameworks. Our Flo Score tells you how each email is likely to perform before you press send.

You’re not typing in a prompt and hoping. You’re sending the kind of email the best in the business would write.

Do I need to know copywriting to use it?

No. That’s the point.

Our Brief Composer asks you a handful of short questions, then writes the email for you. The questions do the marketing thinking so you don’t have to. The copywriting frameworks, marketing strategies and influence tactics, past and present, are baked into every template and email you write. You get the benefit without studying any of them.

If you’d rather write your own brief, you can. There’s a chat-style mode for the advanced users who already know what they want. Either way, the platform supports you.

Why should I trust a brand-new ESP with my deliverability?

Fair question. Here’s why.

GravityFlo runs on Resend, the same modern email infrastructure that powers some of the most reliable senders on the internet. Each workspace gets a custom sending domain. DKIM, SPF and DMARC are auto-configured. Bounces and complaints handled automatically. You don’t have to think about any of it.

Deliverability is one of our pillars. It’s an area we are constantly reviewing and optimising. Because for our customers, the entrepreneurs, creators and founders with lists of 500 to 5,000 subscribers, every email you send needs to land. Every email needs to be opened. Every email needs to do its job. You’ve worked hard to grow your list. We’re not letting a deliverability blip cost you the trust you’ve built.

Is it the real price, or will you be raising it?

It’s the real price. The $29 founding member rate is locked for life. If you’re part of the first 100, it’s yours for as long as you keep your account. Whether that’s for a year or forever. No price hike. No slow creep. Just $29 a month, for as long as you stay.

After the first 100 founding spots are taken, the standard price kicks in at $49 a month. The founding rate exists because we want to reward the people who back us early. $29 a month, locked for life, is our thank you to the ones who started this journey with us. The ones who believed in GravityFlo from the start. The ones who jumped on and joined the ride when we began.

What if I can\u2019t make the live demo?

We’ll send the replay to everyone on the waitlist within 24 hours. Watch it on your time.

But heads up. The first 100 founding member spots open at the live demo and close when they’re gone. If you catch the replay, the spots may already be filled. The standard $49 rate will still be available, and you’ll be welcome to join the platform. But the founding member lifetime price of $29 rewards fast action takers.

“The money is in the list.”

— Dan Kennedy

Email marketing is the marriage between art and science. The science makes the message arrive in the inbox. The art makes someone open it. Most platforms get distracted by everything else. We built GravityFlo to focus on the two things that actually matter. Writing emails. And optimising performance.

This is the platform we wish we had years ago. The one with email at the centre. For the people who already know how much email matters. And for the ones about to find out.

Doors open at the live demo. Save your seat.

Doors open soon. The first 100 founding members with lists up to 2,500 will be claimed live. Lock in $29 a month, for life.

First 100 only

Founding Member

$29/month

Locked for life. For lists up to 2,500 subscribers.

Emails that sound like you, every time. Brand Signature learns your voice from your past sends.
The prompt engineering done for you. Brief Composer asks a few questions and writes the email.
Know how it’ll land before you press send. Flo Score on every email.
Each subscriber gets your email at the time they actually open.
Deliverability handled in the back end. DKIM, SPF, DMARC, dark-mode rendering. All sorted.
The kind of email the best in the business would write. Frameworks of the best marketers, salespeople, copywriters and launch strategists baked in.
Direct line to the founders. Priority support.
Join the waitlist

We\u2019ll save you a seat at the live demo. The first 100 founding members lock in $29/mo for life. For lists up to 2,500.

Got a bigger list? GravityFlo opens Phase 2 for lists between 2,500 and 5,000 subscribers once the founding cohort is settled. Register your interest now to be first in line when doors open.

Register for Phase 2 access

Doors open soon. Be there live. The first 100 spots could disappear fast.

About GravityFlo

GravityFlo is an AI-native email marketing platform built for entrepreneurs, creators and founders with email lists of 500 to 5,000 subscribers. GravityFlo was founded by Natalie Milligan (twenty years in sales and marketing, thirteen years writing copy professionally, founder of The Copy Rebel) and Drew Milligan (technology founder and music industry veteran). GravityFlo is purpose-built for solo and small-team businesses who write their own emails and care about how those emails sound.

GravityFlo's three core features are Brand Signature (AI that learns your voice from your past writing), Brief Composer (a structured briefing flow that does the prompt engineering for you), and Flo Score (a real-time scoring system that predicts subject line strength, readability, and likely engagement before you send). The platform also handles per-subscriber send-time intelligence, Outlook dark-mode preview and auto-fix, and DKIM, SPF and DMARC auto-configuration.

GravityFlo is an alternative to traditional email marketing platforms including Mailchimp, Kit (formerly ConvertKit), Flodesk, Beehiiv, ActiveCampaign, and Klaviyo. Unlike those platforms, GravityFlo focuses on email writing, sending, scoring, and deliverability only, with no CRM, no course builder, no website builder, no SMS dialer, and no customer service inbox. Founding member pricing is $29 per month for life for the first 100 members, with a standard rate of $49 per month after the founding cohort fills.

Learn more about GravityFlo at gravityflo.ai or join the waitlist to attend the live demo and lock in founding member pricing.

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GravityFloAI

AI-native email for entrepreneurs, creators and founders. Less force. More flow. Higher conversions.

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