A Cold Email Copywriting Tool.

Designed to help you find Message-Market Fit .
Powered by data from 2M+ outbound emails every month.

Unifying Nike campaign ROI across channels

Hi John,

I noticed Nike's marketing stack pulls from Salesforce, Sprinklr, and Google Analytics.

If there were a way to add another layer that acted as the glue - letting you instantly pull channel-by-channel ROI on campaigns like Air Max Day or compare athlete partnership performance across regions - would that be useful?

I know now's probably not the best time, given you're likely deep in planning for the Paris Olympics, so no call needed.

For now, would it be ok if I just shared a short video showing how our new proprietary AI tech could make those workflows a lot faster?

The Problem

Most cold emails fail for two reasons:

People don't test enough truly different messages.

And the messages they do test are usually bland and indistinguishable from everyone else's.

Think about it… how many times have you received a cold email that's genuinely made you stop, think, and reply?

The Solution

A tool to help you continuously discover and evolve winning cold email messaging.

To write not just better emails — but continuously generate new ones as old strategies fatigue.

How it works

Enter your company.

We analyse your product, positioning, ICP, pains, and market.

Generate large volumes of truly unique cold emails with AI, using proven templates built from millions of real outbound emails.

Turn messages into campaigns and send at scale through your sequencer.

Rapidly test new angles, narratives, hooks, and offers to find true message-market fit.

Why It's Different

Most copywriting tools

Help you polish a single email.

StackSplit

Is built to generate and test a huge range of genuinely different messaging — pattern-disruptive, creative, human-sounding outreach designed to actually stand out in crowded inboxes.

“

Finding message-market fit is about continuously testing new ideas until you find what truly resonates — not about writing one "perfect" email.

What You Get

Real emails, ready to send

No placeholders. No fluff. Just clean, simple emails.

Multiple angles in seconds

Stop relying on one idea. Test many.

Built for outbound

Everything is designed for cold email, not generic writing.

Works with your stack

Plug straight into tools like Clay and Smartlead.

Who It's For

B2B Sales Reps

Founder-led Sales

GTM Freelancers

Outbound Agencies

If you send cold emails, this is for you.

Features

01 / Template Library

A library of battle-tested outbound templates - flick through and start sending.

100+

Templates

Clusters

Weekly

New drops

Built from real, sent-at-scale campaigns. Pick, remix, or write your own - every template plugs straight into your workflow.

TPL-014Pattern Break

Wrong person? Happy to redirect.

Hey {{first}} - quick question and feel free to ignore if I've got the wrong end of the stick. Are you the one looking after outbound at {{company}}?

Founder-led outbound78w

TPL-027Founder Note

Built this after 3 painful quarters

{{first}} - I'm the founder. Built this thing because I was sick of paying $40k/yr for tools that didn't move the needle. Worth a look?

Founder-led outbound62w

TPL-041Competitor Displacement

Saw you're using Outreach.io - fair warning

Most teams switching off Outreach this year cite the same three reasons. Curious if any of these match what you're hitting at {{company}}?

Competitor displacement91w

TPL-058Free Trial

Free for 14 days, no card needed

Quick one - built a tool that cuts campaign setup from 3 days to 30 minutes. Want me to spin up a workspace for {{company}} so you can poke around?

Free trial offers54w

TPL-072Soft Pitch

Not pitching, just curious

Saw {{company}} just hired 4 SDRs in 60 days - congrats on the ramp. How are you handling list-building and account research at that pace?

Mid-market outbound69w

TPL-089Direct Pitch

3 minutes to show you the demo

Straight to it: we help {{industry}} teams book 2-3x more meetings per SDR without adding tools or headcount. 3 minutes Tuesday or Thursday?

Mid-market outbound48w

TPL-103Event Follow-up

Was great chatting at SaaStr last week

{{first}} - followed up like I said. The thing we were talking about (the AI-account-research bit) - happy to do a 15-min walkthrough whenever suits.

Event follow-up72w

TPL-118Pattern Break

Bad time? Just say the word.

Look, no clever subject line. {{company}} popped up as a fit for what we do. Worth 5 mins or should I move on? Genuinely either's fine.

Founder-led outbound44w

TPL-126Competitor Displacement

Why 30+ teams left {{competitor}} this quarter

Pulled together the top reasons from churn calls. Two stood out - happy to share both even if you stay where you are. Useful context?

Competitor displacement83w

TPL-141Enterprise

For your Q1 GTM planning

{{first}} - most {{industry}} teams of {{size}} are budgeting for outbound tooling this quarter. Worth comparing notes on what's actually working in 2026?

Enterprise outreach79w

TPL-156Soft Pitch

Saw your post on outbound - agreed

Your take on personalisation-at-scale being broken - completely with you. We've been building toward exactly that. Worth a chat to compare notes?

Founder-led outbound56w

TPL-167Free Trial

Try it free - pre-loaded with your data

Already pulled {{company}}'s positioning, pains, and ICP into a workspace. 5-min demo, then it's yours for 14 days, free.

Free trial offers52w

TPL-182Event Follow-up

Promised I'd send the breakdown

Said I'd ping over the framework we were chatting about. Here's the short version - full case study at the end if you want the deep dive.

Event follow-up68w

+87 more

In the library ->

1 / 14 Drag, swipe, or use arrow keys

02 / Workspace

Workspace Intelligence

We analyse your business, product, positioning, ICP, pains, and market to build a deep understanding of what you sell and who you sell to.

03 / Personas

Personas

Create personas by defining your ICP, offer, pain points, industry, and positioning. Select a persona before generating emails so messaging stays tailored to the buyer.

04 / Clusters

Template Clusters

Group templates into strategic clusters for specific use cases.

Examples

Free trial offers
Enterprise outreach
Competitor displacement
Founder-led outbound
Event follow-up campaigns

Run entire messaging strategies against your offer in seconds.

05 / Generate

Email Generation

Generate large volumes of genuinely different cold emails using your selected persona and templates.

06 / Refinement

AI Refinement Tools

Use AI to instantly refine, expand, shorten, or rework messaging variations.

07 / Tools

Message Tools

Turn emails into fully operational outbound assets:

Generate subject lines
Create follow-ups
Build spintax
Generate Clay prompts for scale
Prepare campaigns for sequencers like Smartlead and Clay.

Pricing

One simple plan, everything included.

Single tier

$ 24 / month

Unlimited workspaces
Unlimited email generation
Library of 100+ templates
Complete access to all features and workflow tools

Not sure if this is helpful for your agency?

Join the waitlist now

stacksplit · new-campaign.eml Ready

Stop sending the same tired emails your buyers ignore.

Find messaging that actually gets replies.