Quiet Hours

Background

Klaviyo enables brands to send high-volume SMS and email messages to customers across regions, time zones, and regulatory environments. As SMS adoption increased, so did the legal and operational risk associated with sending messages outside permitted hours.

Quiet Hours was created as a platform-level guardrail that allows brands to define time windows during which messages will not be sent; even if a campaign or flow is triggered. Instead, messages are queued and delivered once Quiet Hours end, based on each recipient’s local time.

This feature was especially critical for SMS, where violations can result in severe fines, class-action lawsuits, and carrier enforcement.

My Role

I led product design for Quiet Hours, a system feature that protects Klaviyo and customers from legal, reputation, and deliverability risks. I worked closely with Product and Content to turn unclear regulations and technical limits into a clear, usable control. As Product Designer, I:

• Structured the end-to-end design process

• Defined the interaction and mental model for Quiet Hours

• Led concept divergence and synthesis

• Ensured designs were system-compliant and immediately shippable

• Partnered with Content to balance clarity, authority, and legal tone

My operating principle throughout was “shape small, ship fast, and reduce risk quickly.”

Team: Messaging Platform / Core Settings
Partners: Product Manager, Content Designer, Engineering Lead, Lead Designer (advisory)
Status: Shipped (Live)

Problem

Brands frequently underestimate the risk of message timing.

Even well-intentioned teams:

• Trigger flows late at night

• Schedule sends in one timezone that reaches recipients in another

• Misinterpret or overlook local regulations

This creates cascading risk:

• Legal exposure (e.g., TCPA, CASL, regional telecom laws)

• Customer trust damage (angry recipients, unsubscribes, spam complaints)

• Carrier penalties (throttling, filtering, or account suspension)

• Support and legal escalations for Klaviyo

From a platform perspective, Klaviyo could not rely on “brands are responsible” as a mitigation strategy. Carriers and regulators increasingly treat platforms as active participants rather than passive tools.

The problem, therefore, was not just how to let brands configure timing, but also how to design a system that accounts for human error, legal ambiguity, and scale.

Constraints & Context

• High urgency: SMS compliance failures carry outsized financial and reputational risk.

• Global complexity: Laws vary by country and region; the safest interpretation must often win.

• Timezone ambiguity: Quiet Hours must be enforced at the recipient level, not the send time level.

• Design system fidelity: All solutions had to use Klaviyo’s existing design system.

• Velocity bias: The feature needed to ship quickly to reduce platform risk.

• Distributed team: PM and I were co-located; Content and Design leadership were remote.

There was no generative user research. Instead, we relied on:

• Competitive analysis

• Internal subject-matter experts (legal, deliverability)

• Platform data and support insights

Design Approach

1. Alignment & Risk Framing

We began with joint PM–Design sessions to align on:

• The regulatory and carrier risks of Quiet Hours need to be mitigated

• The failure modes we were explicitly designing against

• What not to solve in v1 (e.g., per-campaign overrides)

This framing helped us avoid building a flexible but dangerous system.

2. Centralized, Global Mental Model

Rather than embedding Quiet Hours across campaigns, flows, or messages, we designed it as:

• A single, centralized Settings control

• A global best-practice policy

• Applied consistently across applicable messaging surfaces

This reduced cognitive load for brands and reinforced Quiet Hours as a safety default rather than a tactical optimization.

3. Recipient-Level Enforcement

A key design consideration was that Quiet Hours are enforced per recipient, not per send.

This meant the system needed to account for:

• Recipient location and inferred timezone

• Cross-border phone numbers

• Daylight saving changes

• Incomplete or imperfect data

From a UX perspective, this required:

• Abstracting extreme technical complexity

• Communicating behavior clearly without exposing implementation details

• Setting conservative expectations to avoid false confidence

4. Structured Divergence

I explored three concepts:

• Concept A — Out-of-the-Box:
  Minimal configuration using existing Settings patterns.

• Concept B — Guardrails-First:
  A “think big, ship small” approach that prioritized safety, defaults, and future extensibility.

• Concept C — Advanced Control:
  More expressive configuration with higher engineering effort, still system-compliant.

All concepts intentionally avoided bespoke UI patterns or one-off logic.

Given the risk profile, we selected the concept that maximized:

• Predictability

• Speed to production

• Platform-wide safety

Solution

Quiet Hours shipped as a centralized Settings feature that allows brands to define restricted sending windows.

Key characteristics:

• Enforced automatically at the recipient’s local time

• Defaults aligned with conservative legal interpretations

• Clear explanatory copy co-designed with Content

• Applied consistently across relevant messaging surfaces

• No per-object overrides in v1 to preserve compliance integrity

Outcome

• Shipped and live

• Reduced legal and compliance risk for brands

• Improved SMS deliverability and carrier trust

• Lowered support and escalation volume

• Established a scalable foundation for future policy controls

Quiet Hours became a mutual safety feature that protected brands, end customers, and Klaviyo’s platform health simultaneously.

Reflection

Quiet Hours reinforced a core belief in my design practice:

In enterprise platforms, velocity is a risk decision.

By grounding the solution in systems, enforcing conservative defaults, and shipping quickly, we delivered meaningful protection without sacrificing usability or flexibility.