Send-to-Friend Coupons

Subtitle: How to Power Gifting Flows and Referral Coupons Safely

Gift a coupon.
Send a friend $10 to try a service.
Invite someone with a special promo.

These seemingly simple features are powerful growth drivers for many platforms. However, they come with significant privacy and compliance considerations.

Key Principle: “Send-to-friend” features feel personal—but they’re legally sensitive if your platform processes the contact data, regardless of who initiates the sharing.

This article shows how to design gifting and coupon referral flows that delight users without violating privacy laws, balancing growth objectives with compliance requirements.

Foundation

Part of:
Privacy Compliance Playbook for Contact-Based Referral Programs

Supporting reads:

The Consent Playbook – Understanding different types of consent and when each is required
Managing Consent, Retention, and Opt-Out at Scale – Implementing robust systems for handling privacy preferences

What a Send-to-Friend Feature Typically Looks Like

Send-to-friend features typically involve a multi-step process, each with specific privacy implications:

Step	Risk Triggered	Legal Considerations
User enters friend’s email address	Processing third-party personal data	Need lawful basis under GDPR; data minimization requirements
Platform sends coupon invite	Direct marketing rules apply	CAN-SPAM, CASL, and PECR requirements for commercial messages
Contact clicks or ignores invite	Suppression duties and consent boundaries triggered	Obligation to honor opt-outs and maintain suppression lists

The key distinction between send-to-friend features and standard marketing is that the recipient hasn’t directly engaged with your platform. This creates additional obligations:

Transparency about the source: Recipients must understand who sent the message and why they received it
Limited processing scope: The data can only be used for the specific purpose the user intended
Immediate opt-out options: Recipients must be able to easily decline future communications

How to Design Safe Send-to-Friend Features

1. Manual Entry, Not Mass Import

Implementation Guidance:

Design interfaces that encourage thoughtful, individual referrals
Let users enter one or a few contacts manually
Avoid uploading or auto-importing entire address books
Consider implementing a “recent contacts” feature that shows only contacts the user has recently referred

Why This Matters:

Manual entry ensures each referral is intentional
Reduces the risk of accidental mass messaging
Aligns with GDPR’s data minimization principle
Creates higher-quality referrals with better conversion rates

Implementation Example:

<!-- Good Implementation: Manual Entry -->
<div class="send-coupon-form">
  <h3>Send a $10 coupon to a friend</h3>
  <form>
    <div class="form-group">
      <label for="friend-email">Friend's Email:</label>
      <input type="email" id="friend-email" required>
    </div>
    <div class="form-group">
      <label for="personal-message">Add a personal message (optional):</label>
      <textarea id="personal-message" maxlength="200"></textarea>
    </div>
    <button type="submit">Preview Coupon Message</button>
  </form>
</div>

2. Message Preview and Consent

Implementation Guidance:

Show exactly what the invite will say, including sender information and any platform branding
Include all elements that will appear in the final message
Require explicit user confirmation before sending
Allow users to edit the message within compliance boundaries

Why This Matters:

Creates an additional consent checkpoint
Ensures transparency about what will be sent
Reduces the risk of user complaints about unexpected messaging
Provides documentation of user intent for compliance purposes

Example Preview Screen:

----- PREVIEW -----
From: [Platform Name] on behalf of [User Name]
To: friend@email.com
Subject: [User Name] sent you a $10 coupon for [Platform]

Message:
[User Name] thought you might enjoy [Platform] and sent you a $10 coupon to try it out.

[Personal message if provided]

[Coupon details and redemption instructions]

This message was sent by [Platform Name] because [User Name] asked us to share this coupon with you. We respect your privacy and won't send you further messages unless you sign up. [Unsubscribe link]
----- END PREVIEW -----

"You are about to send this coupon to friend@email.com. Confirm?"
[Cancel] [Send Coupon]

For more guidance on designing transparent user experiences, see: Privacy UX

3. Clear Invitation Content

Every coupon invite should include specific elements to ensure compliance with marketing regulations:

Required Elements:

Sender identity that clearly identifies both the user and your platform (“Sent by Alex via [Platform]”)
Purpose of the message (e.g., “Alex wanted to share this coupon with you”)
Clear explanation of the offer or coupon
Unsubscribe/opt-out link for the recipient
Link to your privacy policy
If applicable, your physical address (required by CAN-SPAM)

Message Structure Best Practices:

Subject Line: Be clear and honest about the content (e.g., “[Friend] sent you a coupon for [Platform]”)
Opening: Immediately identify who sent the coupon and why
Body: Keep it concise, focusing on the coupon details and redemption instructions
Footer: Include all required compliance elements (opt-out, privacy policy, etc.)

Example Implementation:

<!-- Email Template for Coupon Sharing -->
<div class="email-container">
  <div class="email-header">
    <img src="logo.png" alt="[Platform] Logo">
    <h1>[Friend's Name] sent you a $10 coupon</h1>
  </div>

  <div class="email-body">
    <p>[Friend's Name] thought you might enjoy [Platform] and wanted to share this coupon with you.</p>

    <p class="personal-message">"[Personal message from friend]"</p>

    <div class="coupon-container">
      <h2>$10 OFF Your First Purchase</h2>
      <p>Use code: FRIEND10</p>
      <a href="[redemption-url]" class="coupon-button">Redeem Now</a>
    </div>

    <p>This coupon expires on [date].</p>
  </div>

  <div class="email-footer">
    <p>This message was sent by [Platform] because [Friend's Name] asked us to share this coupon with you.</p>
    <p>We respect your privacy and won't send you further messages unless you sign up.</p>
    <p><a href="[unsubscribe-url]">Click here</a> to opt out of future invitations.</p>
    <p><a href="[privacy-policy-url]">Privacy Policy</a></p>
    <p>[Physical address as required by CAN-SPAM]</p>
  </div>
</div>

For more detailed guidance on crafting compliant invitation messages, see: Crafting Compliant Invitation Content and Messaging

4. One-Time Messaging Only

Implementation Guidance:

Send the invite once and only once
No automatic reminders or “nudge your friend” flows unless the invitee explicitly opts in
If the user wants to resend, require them to go through the entire process again
Consider implementing a frequency cap for the same recipient

Why This Matters:

Avoids triggering anti-spam regulations
Respects the recipient’s attention and inbox
Prevents potential legal issues like those in the LinkedIn case (where follow-up emails led to a $13M settlement)
Maintains the personal nature of the referral

Technical Implementation:

Store a record of sent invitations with timestamps
Check against this record before allowing new sends to the same address
Implement a cooling-off period before allowing resends to the same recipient

5. Post-Send Suppression

Implementation Guidance:

Maintain a suppression list for recipients who:
- Unsubscribe or opt out
- Mark the message as spam
- Request “no future invites”
Use cryptographic hashing to store these preferences securely
Check against this suppression list before sending any new invitations
Honor these preferences globally across your platform

Technical Implementation:


def can_send_invitation(recipient_email):
    # Hash the email for privacy-preserving lookup
    hashed_email = secure_hash(recipient_email.lower())

    # Check if in suppression list
    if is_in_suppression_list(hashed_email):
        return False

    # Check frequency cap
    last_invite_time = get_last_invite_time(hashed_email)
    if last_invite_time and (current_time() - last_invite_time < MINIMUM_INTERVAL):
        return False

    return True

For more detailed guidance on implementing suppression lists and managing opt-outs, see: Post-Send Obligations

Real-World Example: Uber and Unroll.me Fallout

The Unroll.me case provides a cautionary tale about misusing data collected through referral and sharing features:

What Happened:

Unroll.me offered a service to help users unsubscribe from unwanted emails
The company scanned users’ inboxes, including sent coupons and invites
Unroll.me then sold this data to Uber, which used it to gather intelligence on Lyft (a competitor)
The New York Times exposed this practice in 2017

The Consequences:

Immediate and severe backlash from users
Significant damage to both companies’ reputations
Loss of user trust and account cancellations
Regulatory scrutiny and privacy investigations
Long-term brand damage that persisted for years

Key Lesson: Never use or sell contact data beyond the explicitly agreed use. The short-term gain from monetizing this data is far outweighed by the potential long-term damage to your brand and user trust.

(Source)

Legal Requirements for Send-to-Friend Flows

Send-to-friend features must comply with various regional regulations:

Region	Key Rules	Implementation Requirements
GDPR (EU/UK)	Consent for processing and messaging	Need lawful basis for processing; clear disclosure of data use; opt-out mechanism
PECR (EU/UK)	Specific rules for electronic marketing	Identify sender clearly; provide opt-out mechanism; don’t disguise marketing
CASL (Canada)	Express consent; strict one-time messaging rules	Clear identification of sender; unsubscribe mechanism; physical address
CAN-SPAM (USA)	Sender disclosure + opt-out required	Accurate header information; clear opt-out; physical postal address
CPRA (California)	Notice of financial incentives if rewards involved	Disclose value exchange if offering incentives for referrals

Cross-Jurisdictional Compliance Strategy:

To ensure global compliance, implement the strictest requirements across all regions:

Obtain clear consent before sending any communications
Provide transparent information about how the data will be used
Include all required disclosures in the message
Implement robust opt-out mechanisms that are honored immediately
Document your compliance measures for accountability purposes

Mistakes to Avoid

Common implementation errors can create significant legal and reputational risks:

Mistake	Risk	Better Alternative
Auto-importing contacts for coupon sends	Coerces consent; GDPR violation	Require manual entry of each recipient
Mass messaging without preview	Breaches transparency standards	Show exact preview and require confirmation
Hiding opt-out links	Triggers spam penalties under CAN-SPAM and PECR	Make opt-out mechanisms prominent and easy to use
Using invite data for unrelated marketing	Secondary use violation under GDPR and CPRA	Use data only for the specific purpose disclosed
Sending automatic reminders	Violates one-time messaging rules	Only send additional messages with explicit consent
Not maintaining suppression lists	Regulatory violations and reputation damage	Implement robust suppression mechanisms

Case Study: Path’s Contact Controversy

The social network Path faced significant backlash and an FTC settlement after it was discovered that their mobile app was uploading users’ entire address books without clear disclosure or consent. The company was required to establish a comprehensive privacy program and pay an $800,000 civil penalty.

Key Lesson: Always be transparent about what contact data you’re collecting and how you’ll use it. Obtain explicit consent before accessing users’ contact information.

Summary: Delight, Don’t Spam

Effective, compliant send-to-friend features balance growth objectives with privacy requirements:

Strategy	Benefit	Implementation Approach
Manual, one-by-one entry	Safer, more intentional outreach	Design interfaces that encourage thoughtful referrals
Transparent messaging	Higher coupon redemption rates	Show exactly what will be sent and require confirmation
Fast suppression of opt-outs	Regulatory protection	Implement robust suppression mechanisms
Reward after signup	Better growth and user trust	Structure incentives to reward conversions, not just sends

Best Practices for Sustainable Coupon Sharing:

Respect recipients
- Treat every recipient as a potential user with privacy rights
- Send only what the user explicitly approved
- Honor opt-outs immediately and globally
Reward actions, not sends
- Structure incentives to reward successful conversions
- Avoid rewarding users simply for sending mass invitations
- Consider progressive rewards that increase with recipient engagement
Build trust-first gifting flows
- Design the entire experience to feel personal and respectful
- Ensure the recipient experience matches what the sender expects
- Focus on long-term relationship building, not short-term metrics

By designing send-to-friend features with privacy and compliance in mind from the beginning, you can create sustainable growth channels that build trust rather than regulatory risk.

Up Next

Read Wishlist and Registries to learn about implementing compliant wishlist sharing features.

Or revisit contact-based suppression standards:
Post-Send Obligations

Foundation

What a Send-to-Friend Feature Typically Looks Like

How to Design Safe Send-to-Friend Features

1. Manual Entry, Not Mass Import

2. Message Preview and Consent

3. Clear Invitation Content

4. One-Time Messaging Only

5. Post-Send Suppression

Real-World Example: Uber and Unroll.me Fallout

Legal Requirements for Send-to-Friend Flows

Mistakes to Avoid

Summary: Delight, Don’t Spam

Up Next

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