Klaviyo Signup Forms & Popups: The List-Growth Guide

Quick answer: Klaviyo signup forms come in three types — popups (highest opt-in, ~3–6% conversion), flyouts (less intrusive, always-on), and embedded forms (for footers and landing pages). Build them in Klaviyo’s form editor, trigger on time/exit-intent/scroll, capture email and SMS consent, and connect them to your welcome flow so every new subscriber is greeted automatically.

Key takeaways

• Popup, flyout, embedded — each fits a different goal; most stores use all three.
• Display triggers (time, exit-intent, scroll, page) decide how well a form converts.
• Always capture explicit SMS consent with a clear checkbox if you want to text.
• Connect forms to the welcome flow so signups convert into first orders.
• A/B test the offer, trigger, and design — small changes move opt-in rates a lot.

Your flows can only email people who’ve subscribed — which makes list growth the fuel for everything else. This guide covers building Klaviyo forms that actually convert. It’s a cluster of our complete Klaviyo flows guide.

Form types: popup, flyout, or embedded?

Each form type serves a different purpose:

• Popup — a center-screen overlay; the highest opt-in rate (~3–6%). Best on entry or exit-intent.
• Flyout — slides in from a corner; less intrusive, good for always-on list growth (~1–3%).
• Embedded — sits inside the page; unintrusive, ideal for footers, blog posts, and dedicated landing pages.

Most stores run a popup for the headline offer plus an embedded form in the footer to catch the rest.

Display triggers that convert

A form’s trigger matters as much as its design:

• Time delay: show after a few seconds, not instantly — let visitors orient first.
• Exit-intent: trigger when the cursor heads for the close button; catches leavers without interrupting browsers.
• Scroll depth: show after someone scrolls 40–50% — a signal of genuine interest.
• Page targeting: different offers on different pages (a category-specific incentive converts better than a generic one).

Design and copy that converts

• Lead with the value, not “subscribe.” “Get 10% off your first order” beats “Join our newsletter.”
• Minimize fields — email (and optional SMS) is plenty; every extra field lowers completion.
• One clear CTA button with action copy (“Claim my 10%”).
• On-brand and mobile-first — most signups happen on phones.

Teaser and multi-step forms

• Teaser: a small tab that sits in the corner and expands when clicked — recovers people who dismissed the popup without re-interrupting them.
• Multi-step: ask for email first, then SMS (or a preference) on step two. You capture the email even if they drop off, and step two lifts SMS opt-ins significantly.

Capturing email + SMS consent

If you want to send SMS, the form must capture explicit consent — a clear, unchecked checkbox with terms, not a pre-ticked box. Log the consent properly so you stay compliant; the rules are in our Klaviyo SMS marketing guide. A multi-step form is the cleanest way to collect both email and phone.

A/B testing your forms

Klaviyo lets you A/B test forms — test one variable at a time: the offer (10% vs free shipping), the headline, the trigger timing, or the design. Opt-in rate is sensitive to all of these, so testing compounds quickly. Keep the winner and test the next variable.

Connecting forms to the welcome flow

A form without a welcome flow is a wasted opportunity. Point your form at the list that triggers your welcome series, so every subscriber is greeted and nudged toward a first purchase within minutes. Then use segments to tailor the experience by source.

Benchmarks

• Popup conversion: ~3–6% is healthy; above that is excellent.
• Flyout / embedded: ~1–3%.
• Track opt-in rate per form and improve it with testing. Klaviyo’s forms documentation covers the builder in detail.

Frequently asked questions

What’s the best type of Klaviyo signup form?

Popups have the highest opt-in rate (~3–6%), but the best setup usually combines a popup for your headline offer with an embedded footer form and a teaser to recover dismissals. Match the form type to the placement and goal.

What’s a good conversion rate for a Klaviyo popup?

Around 3–6% of visitors is healthy for a popup with a clear offer; flyouts and embedded forms typically convert 1–3%. A/B testing the offer and trigger can push these higher.

How do I capture SMS consent in a Klaviyo form?

Add an explicit, unchecked consent checkbox with clear terms — never pre-ticked. A multi-step form (email first, phone second) is the cleanest way to collect both while staying compliant.

How do I connect a signup form to my welcome flow?

Point the form at the list that triggers your welcome series. When a subscriber joins that list, the welcome flow fires automatically and greets them within minutes.

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About the author

Ravinder is the founder of Excelohunt, a Klaviyo-focused email & SMS agency. We build list-growth systems that fill ecommerce funnels.

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