Taking on new D2C brands. Book your free email audit.
Inbox Theory
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Free email audit
How we work

A clear plan before anything is built

Four steps from first look to steady improvement, with no surprises along the way.

Start with an audit
01
Free audit

We review your current emails, flows, sign-up points and design, then tell you plainly what is working and what is not.

02
Plan

One roadmap covering copy, design and sending, agreed with you before any work starts.

03
Build and QA

We write, design, build and test every email across devices and inboxes before it ships.

04
Send and improve

We launch, read the results, run tests and refine, so the program gets better each month.

Inbox Theory vs going it alone

An honest look at the trade-offs.

Inbox Theory
✓Email and design under one roof
✓Klaviyo and Mailchimp ready
✓Clear plan before we build
✓Brand consistent everywhere
Doing it in-house
✕Copy and design split across tools
✕Hiring and ramp-up time
✕Generalists covering everything
✕Email often last on the list
Proof, not promises

Real numbers from a real D2C brand

Straight from the Klaviyo account of a brand we work with. The name stays private, the numbers do not.

$81,110.54
Total revenue, Aug 29 to Sep 28, 2026
▲ 26% vs previous period
$46,916.08
Revenue attributed to email and SMS in the same period
▲ 38% vs previous period
57.84%
Of total revenue came from Klaviyo channels
$201,424.61
Total revenue, Jul 1 to Sep 28, 2026, with $109,377.20 attributed (54.30%)
▲ 4% vs previous period
Attributed revenue by type, Jul 1 to Sep 28, 2026
Campaigns 64.67%
Flows 35.33%
Campaigns: $70,730.89Flows: $38,646.31
Attributed revenue by channel, same period
Email 78.18%
SMS 21.82%
Email: $85,510.62SMS: $23,866.58
Klaviyo business performance summary, Jul 1 to Sep 28 2026
Klaviyo dashboard, Jul 1 to Sep 28, 2026
Klaviyo business performance summary, Aug 29 to Sep 28 2026
Klaviyo dashboard, Aug 29 to Sep 28, 2026

Source: Klaviyo business performance summary. Attributed revenue is the revenue Klaviyo credits to email and SMS.

Why trust us

How we earn your trust

01
See it before you buy it

A free audit comes first, with no obligation to continue.

02
Nothing is a black box

One clear plan is agreed with you before anything is built.

03
Quality is checked

Every email is tested across devices before it ships.

04
Results in the open

We show real account data, like the numbers above.

Common questions

Which platforms do you use?

Klaviyo mainly, and Mailchimp when it fits your setup.

Do you work with any D2C brand?

Yes. We work across D2C categories.

Can we see past results?

We share results and examples on a call.

What does the audit cost?

Nothing. It is free and comes with no obligation.

Let's make your inbox earn its keep

Send us your brand and get a free email audit. No pitch deck, no obligation.

Get your free audit
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Inbox Theory

Email and design studio for D2C brands. We turn one-time buyers into repeat customers.

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