Does Modular Mail integrate directly with Klaviyo?

No, and that's intentional. Modular Mail is ESP-agnostic. You build campaigns in the editor and export clean HTML, then upload to Klaviyo as a template or paste into a flow. No API integration to maintain; no platform lock-in.

How do Klaviyo personalisation variables work?

You export clean HTML from Modular Mail, then add Klaviyo variables (like {{ first_name }} or product loop syntax) directly in Klaviyo's template editor after uploading. Modular Mail handles the design structure; Klaviyo handles the personalisation.

Can I use this for Klaviyo flows?

Yes. Export the HTML from Modular Mail and paste it into any Klaviyo flow email. The workflow is the same whether you're building a one-off campaign or an automated flow message.

What about dynamic product recommendations?

Klaviyo's dynamic product blocks use Klaviyo's own data layer and are added inside Klaviyo after you upload the HTML. The product grid module in Modular Mail defines the visual structure. Klaviyo populates the product data.

Can my team use this without a developer day-to-day?

Yes. Template setup is a one-time developer task. After that, your marketing team builds campaigns using content fields in the editor. No HTML knowledge needed. Dev only gets involved when you want a new module.

Does it replace Klaviyo?

No. Modular Mail replaces the template-building and campaign-content step. You still use Klaviyo for sending, segmentation, flow automation, A/B testing, and analytics. The two work alongside each other.

Can I use existing Klaviyo templates?

Yes. A developer can convert your existing HTML templates into Modular Mail modules by adding mm-editable tags. We also offer professional template conversion as a service.

For Klaviyo teams

A CMS for your Klaviyo email templates.

Modular Mail is an email CMS. Your ecommerce template library is configured with locked modules and editable content fields. Marketers build campaigns by filling in fields, then export clean HTML to Klaviyo. Consistent design across every flow and weekly send.

Book a demo Try the editor

The challenge

Why Klaviyo teams add a CMS layer

Klaviyo is strong for ecommerce: segmentation, flows, SMS, analytics, and product data. Building email content consistently across flows and weekly sends is the part that gets messy.

Drag-and-drop works, until it doesn't

Klaviyo's drag-and-drop editor is good for quick campaigns. As your programme grows and multiple people start building emails, design consistency starts to drift. Button colours, font choices, spacing: every small deviation accumulates.

Custom HTML templates need a developer

Klaviyo supports custom HTML templates, which is exactly what design-conscious brands want. But every update to that HTML means another developer ticket. For teams sending weekly, the queue becomes a bottleneck.

Product grid complexity

Ecommerce emails live and die on the product grid. Getting the structure, image ratios, and typography exactly right every time requires precision. Free-form editing makes that precision hard to maintain at volume.

Consistency across flows

A welcome flow, an abandoned cart flow, and a win-back flow should all feel like they come from the same brand. When each is built independently in a drag-and-drop editor, that consistency depends entirely on team discipline. A locked template system makes it automatic.

If you manage Klaviyo for multiple clients as an agency, see how agencies use Modular Mail.

Common challenges

Where Klaviyo email programmes hit friction

These are the patterns we hear most from ecommerce teams using Klaviyo at scale.

Scaling across flows and campaigns

Keeping design consistent across welcome flows, abandoned cart, win-back, and weekly promotions is hard when each one is built separately in a drag-and-drop editor.

Custom HTML means developer dependency

Custom HTML templates keep the design locked, but every update needs a developer. Content changes, test variants, and new campaigns all wait in the queue.

Seasonal campaigns at volume

Ecommerce teams running weekly promotional emails can't afford a dev round-trip on each one. The volume demands a system where marketers build campaigns without technical help.

Brand drift across product grids

Product grids, hero banners, and promotional modules need to match the brand every time. Free-form editing in a drag-and-drop editor means spacing, fonts, and colours drift.

How it works

Three steps from template to a sent campaign

Your module library is configured once. After that, your team builds every campaign from the same tested components.

01

Configure your template system

Your developer, agency, or our team sets up your module library in Modular Mail: hero, product grid, USP, CTA, footer, and any custom layouts your programme needs. Structure is locked with mm-editable tags. See the template setup service.
02

Build campaigns in the editor

Marketers pick modules, fill in product copy, upload images, and reorder sections. Preview renders live on desktop and mobile. AI Copy Assistant helps with subject lines and body copy.
03

Export clean HTML to Klaviyo

One-click export produces clean HTML. Upload to Klaviyo as a template or paste it into a specific flow email or campaign. Add Klaviyo personalisation variables after upload.

The editor

What your team sees

A clean editor over a locked template library. Pick a module, fill in content fields, preview, export.

Your product grids, heroes, and CTAs look the same every time. The only variable is the content.

Locked module structure

Product grids, heroes, and CTAs stay on-brand every time.
Content fields, not code

Text, images, links, and CTAs are simple fields. No HTML in sight.
Drag-and-drop modules

Pick the modules you need and drag them into order.
Live preview

Desktop and mobile preview as you type. No guessing.
AI Copy Assistant

Generate subject lines and body copy in your brand voice.
Clean Klaviyo export

One-click HTML export. Upload to Klaviyo in minutes.

Book a demo Try the editor

Modular Mail editor showing an ecommerce email campaign with product modules

Comparison

Klaviyo native versus Klaviyo with Modular Mail

A factual comparison. Add Modular Mail as a CMS layer; keep Klaviyo for sending, flows, and analytics.

Feature	Klaviyo email editor	Klaviyo + Modular Mail Recommended
Template setup	Drag-and-drop blocks or custom HTML editor	Standard HTML with mm-editable tags
Brand guardrails	Limited; users can adjust styles in drag-and-drop	Locked structure; only content fields are editable
Product grids	Dynamic product blocks with Klaviyo data	Module structure locked in Modular Mail; dynamic product data added in Klaviyo after export
Consistency across flows	Depends on team discipline	Same module library used everywhere; consistency built in
Who can build campaigns	Anyone, with risk of design drift	Anyone. Structure is locked, only content is editable
ESP portability	Klaviyo-specific editor	Export clean HTML to any ESP
Preview and testing	Klaviyo preview; separate tools for rendering tests	Live desktop and mobile preview, plus Litmus / EoA integration

Use cases

Who uses Modular Mail with Klaviyo

DTC and ecommerce brands

Brands sending weekly promotions, product launches, and seasonal campaigns alongside automated flows need a system that holds the design together at volume.

A DTC brand sends weekly promotions and runs flows for welcome, abandonment, and win-back. The template library is set up once in Modular Mail. The email team builds every send from the same tested modules.

Subscription and replenishment brands

Brands with recurring purchase cycles send a predictable mix of reorder reminders, loyalty updates, and promotional pushes. A locked template system keeps every send on-brand without adding manual overhead.

A subscription skincare brand runs monthly reorder reminders alongside new product launches. Each email is built from the same tested module library. The design stays consistent whether the send is automated or one-off.

In-house ecommerce teams scaling up

Growing ecommerce teams adding headcount to their email function need to bring new team members up to speed without giving them access to raw HTML.

An ecommerce team growing from one email person to three needs a system that any team member can use safely. Modular Mail gives each person access to the same module library, with no risk of breaking the design.

FAQ

Modular Mail with Klaviyo, in detail

Does Modular Mail integrate directly with Klaviyo?

No, and that's intentional. Modular Mail is ESP-agnostic. You build campaigns in the editor and export clean HTML, then upload to Klaviyo as a template or paste into a flow. No API integration to maintain; no platform lock-in.
How do Klaviyo personalisation variables work?

You export clean HTML from Modular Mail, then add Klaviyo variables (like {{ first_name }} or product loop syntax) directly in Klaviyo's template editor after uploading. Modular Mail handles the design structure; Klaviyo handles the personalisation.
Can I use this for Klaviyo flows?

Yes. Export the HTML from Modular Mail and paste it into any Klaviyo flow email. The workflow is the same whether you're building a one-off campaign or an automated flow message.
What about dynamic product recommendations?

Klaviyo's dynamic product blocks use Klaviyo's own data layer and are added inside Klaviyo after you upload the HTML. The product grid module in Modular Mail defines the visual structure. Klaviyo populates the product data.
Can my team use this without a developer day-to-day?

Yes. Template setup is a one-time developer task. After that, your marketing team builds campaigns using content fields in the editor. No HTML knowledge needed. Dev only gets involved when you want a new module.
Does it replace Klaviyo?

No. Modular Mail replaces the template-building and campaign-content step. You still use Klaviyo for sending, segmentation, flow automation, A/B testing, and analytics. The two work alongside each other.
Can I use existing Klaviyo templates?

Yes. A developer can convert your existing HTML templates into Modular Mail modules by adding mm-editable tags. We also offer professional template conversion as a service.