Communication Channels Overview

Overview of available communication channels in the Zixflow event system, their capabilities, delivery mechanisms, and when to use each channel. Currently implemented: Push notifications. Future channels documented for reference only.

What are Communication Channels?

Communication channels are the different ways you can reach your users to deliver messages, notifications, or content. Each channel has unique characteristics, delivery mechanisms, and use cases. Think of channels as the delivery methods for your messages — like choosing between calling someone, texting them, emailing them, or knocking on their door. Each method works differently and is appropriate for different situations.

The Simple Definition

A communication channel is a pathway through which you send messages from your product to your users. Examples:

Push notifications: Alert that appears on their phone lock screen
Email: Message delivered to their inbox
In-app messages: Banner or modal that appears while they’re using your app
SMS: Text message to their phone number

Why Multiple Channels Matter

Different channels excel at different things:

Urgency varies: Push for “Your order shipped!” (immediate), Email for “Here’s our monthly newsletter” (can wait)
Content complexity differs: Email can include rich HTML and images, Push has 1-2 lines of text
User availability changes: In-app messages reach active users, Email reaches everyone (even if they haven’t opened your app in weeks)
Permission requirements differ: Push requires explicit permission, Email just needs an email address
Engagement patterns vary: Some users check email religiously, others ignore it but always tap push notifications

How Channels Work Together

Smart messaging uses multiple channels in coordination: Example: Abandoned cart recovery

1 hour later: In-app message (if they’re still browsing)
3 hours later: Push notification (quick reminder)
24 hours later: Email (detailed reminder with product images)
3 days later: SMS (final urgent reminder with discount code)

Each channel plays to its strengths: in-app for immediate context, push for quick attention, email for rich content, SMS for urgent final appeal.

Channel Characteristics to Consider

Reach: How many users can you message?

Email: Nearly universal (most users provide email)
Push: Requires app install + permission (50-70% grant rate)
In-app: Only active users (subset of total users)
SMS: Requires phone number + explicit opt-in (5-20% typically)

Speed: How fast does message arrive?

Push: <5 seconds (real-time)
SMS: <10 seconds (near real-time)
In-app: Instant (but only when app is open)
Email: <1 minute (but users check infrequently)

Visibility: How likely are they to see it?

Push: Very high (lock screen, notification badge)
SMS: Very high (most people read texts immediately)
In-app: High (if they’re actively using app)
Email: Medium-low (cluttered inboxes, spam filters)

Cost: What does each message cost?

Push: Free (after platform fees)
Email: ~ $0.0001 -$ 0.001 per email
In-app: Free
SMS: ~ $0.01 -$ 0.05 per message

Content richness: How much can you say?

Email: Unlimited (HTML, images, videos, buttons)
In-app: High (full app UI capabilities)
Push: Low (1-2 lines of text, maybe image)
SMS: Very low (160 characters, plain text)

Choosing the Right Channel

Ask yourself:

How urgent is this message?
- Critical/immediate → Push or SMS
- Important but not urgent → Email
- FYI/nice-to-have → In-app
How much information do I need to convey?
- Quick alert → Push or SMS
- Detailed explanation → Email
- Interactive experience → In-app
Where is the user right now?
- In the app → In-app message
- Away from app → Push or Email
- Unknown → Email (reaches everyone)
What action do I want them to take?
- Immediate action → Push (tap to open app)
- Considered decision → Email (read details, think, decide)
- In-app behavior → In-app message (“Try this feature”)

Available Channels

Channel Opt-Out Model

Every user profile stores an opt-out status for each channel. The system uses three states:

Status	Value	Meaning
`NOT_OPTED_OUT`	1	User is reachable on this channel (default for Push, SMS, WhatsApp, RCS)
`OPTED_OUT`	2	User explicitly opted out — all sends suppressed
`UNKNOWN`	3	Intent not yet established (default for Email — pending confirmation)

Each channel also stores an _opt_out_at timestamp recording when the opt-out occurred. Setting opt-out status via SDK:

// User opts out of SMS
Zixflow.instance.setProfileAttributes({
  'sms_opt_out': 2,        // OPTED_OUT
  'sms_opt_out_at': DateTime.now().toIso8601String(),
});

// User opts back in to push
Zixflow.instance.setProfileAttributes({
  'push_opt_out': 1,       // NOT_OPTED_OUT
});

User Suppression (blocks ALL channels at once):

// Triggered server-side via lifecycle event "User Suppressed"
// Sets is_suppressed = true on the profile — no outbound messages of any kind
// Reversed by "User Unsuppressed" lifecycle event

See User Preferences & Consent for full preference management.

1. Push Notifications ✅ IMPLEMENTED

Platform: Mobile apps (iOS, Android) Delivery: Apple Push Notification service (APNs) and Firebase Cloud Messaging (FCM) Latency: <5 seconds (real-time) Opt-in required: Yes (system permission dialog) Opt-out field: push_opt_out (default: NOT_OPTED_OUT) What’s implemented:

✅ Device token registration (profile_devices table)
✅ Multi-device support (one user = N tokens)
✅ Platform routing (iOS via APNs, Android via FCM)
✅ push_opt_out / push_opt_out_at fields on user profile
✅ Deep linking support

When to use:

Time-sensitive transactional alerts (order shipped, payment failed)
Re-engagement (dormant users, abandoned cart)
Real-time updates (price drop, new message)

2. Email

Platform: Universal (all devices with email client) Delivery: SMTP via SendGrid/AWS SES (planned) Latency: <1 minute Opt-in required: Yes (CAN-SPAM, GDPR compliance) Opt-out field: email_opt_out (default: UNKNOWN — email defaults to pending confirmation unlike other channels) When to use:

Complex onboarding sequences
Transactional receipts (order confirmations, invoices)
Newsletters and product updates

Not yet available. The email_opt_out / email_opt_out_at fields are already stored on user profiles.

3. SMS

Platform: Mobile phones (all devices) Delivery: Twilio/AWS SNS (planned) Latency: <10 seconds Opt-in required: Yes (TCPA compliance in US) Opt-out field: sms_opt_out (default: NOT_OPTED_OUT) When to use:

Critical alerts (fraud detection, account security)
Two-factor authentication codes
Time-sensitive transactions (delivery today, pickup ready)

Not yet available. The sms_opt_out / sms_opt_out_at fields are already stored on user profiles in preparation for SMS delivery.

4. In-App Messages

Platform: Mobile apps (while app is open) Delivery: SDK renders message in-app Latency: Real-time (no server delay) Opt-in required: No (native to app experience) When to use:

Feature announcements (new feature available on this screen)
Tooltips/onboarding (guide users through workflows)
Upsell prompts (hit paywall → show upgrade modal)

Not yet available.

5. WhatsApp

Opt-out field: whatsapp_opt_out (default: NOT_OPTED_OUT) Not yet available. The whatsapp_opt_out / whatsapp_opt_out_at fields are already stored on user profiles.

6. RCS (Rich Communication Services)

Opt-out field: rcs_opt_out (default: NOT_OPTED_OUT) Not yet available. The rcs_opt_out / rcs_opt_out_at fields are already stored on user profiles.

7. Web Push

Platform: Web browsers (Chrome, Firefox, Safari 16+) Delivery: Browser Push API Latency: <5 seconds Opt-in required: Yes (browser permission) Not yet available.

Channel Selection Matrix

Use Case	Best Channel	Backup Channel	Rationale
Order shipped	Push	Email	Real-time + tracking link
Cart abandoned (2h)	Push	Email	Immediate reminder while intent is high
Cart abandoned (24h)	Email	Push	Longer content, include product images
Password reset	Push + Email	SMS	Both for redundancy, SMS for critical security
Weekly newsletter	Email	N/A	Rich content, not time-sensitive
Flash sale (4 hours)	Push	SMS	Urgency + broad reach
Feature announcement	In-App	Push	Contextual (show when user would use it)
Payment failed	Email	Push	Important, needs resolution steps (complex)
Trial ending (3 days)	Email	Push	Detailed upgrade info, pricing comparison
User inactive 14 days	Push	Email	Re-engage quickly, low friction

Multi-Channel Orchestration

Sequential Delivery

Use case: Maximize reach by trying multiple channels

Campaign: Cart Abandonment Recovery
Step 1 (2 hours after cart add):
  Channel: Push
  Fallback: If push not delivered within 10 minutes → Send Email
  
Step 2 (24 hours):
  Channel: Email
  Condition: If no Order Completed
  
Step 3 (72 hours):
  Channel: Push + Email
  Condition: If no Order Completed
  Offer: 15% discount

Implementation note: Multi-channel orchestration not yet built. Currently push-only.

Preference-Based Routing

Use case: Respect user’s channel preferences

// User sets preferences
setProfileAttributes({
  notification_preferences: {
    transactional: ['push', 'email'],     // Send both
    promotional: ['email'],                // Email only
    product_updates: ['push']              // Push only
  }
});

// Campaign respects preferences
Campaign: Product Launch
Category: product_updates
→ System checks user preferences
→ Sends via 'push' only (per user preference)

Implementation note: Preference management not yet built.

Channel Suppression

Use case: Don’t send via channel if user recently engaged elsewhere

User receives Order Shipped email at 10:00 AM
User opens email at 10:05 AM
→ Suppress push notification scheduled for 10:10 AM
   (User already engaged, no need for redundant push)

Implementation note: Cross-channel suppression not yet built.

Performance Benchmarks

Industry Averages (2026)

Push Notifications:

Permission grant rate: 60% (iOS), 80% (Android)
Delivery rate: 95% (devices online within 7 days)
Open rate: 5-10% (promotional), 15-25% (transactional)
Click-through rate: 40-60% of opens

Email:

Deliverability rate: 95% (excluding bounces)
Open rate: 15-25% (promotional), 30-50% (transactional)
Click-through rate: 2-5% (promotional), 10-20% (transactional)
Unsubscribe rate: 0.1-0.5% per send

SMS:

Delivery rate: 98%
Open rate: 98% (within 3 minutes)
Click-through rate: 15-30%
Opt-out rate: 1-3% per send

In-App Messages:

Display rate: 100% (if conditions met)
Dismissal rate: 30-50% (without action)
Action rate: 5-15% (click CTA)

Cost Comparison

Channel	Cost per Message	Monthly Cost (100k users)	Notes
Push	$0	$0	Free (only infrastructure costs)
Email	$0.0001-0.001	$10-100	Volume pricing, SendGrid/SES
SMS	$0.01-0.05	$1,000-5,000	Expensive, use sparingly
In-App	$0	$0	Free (part of app)
Web Push	$0.0001	$10	Browser infrastructure costs

ROI considerations:

Push: Highest ROI for mobile apps (free + high engagement)
Email: Best for complex content, nurture campaigns
SMS: Reserve for high-value conversions (abandoned cart $500+)
In-App: Best for onboarding, feature adoption

Channel-Specific Best Practices

Push Notifications

✅ Do:

Request permission after showing value
Personalize with user’s name, behavior
Use emojis sparingly (draws attention)
Include clear CTA and deep link
Respect quiet hours (9am-9pm)

❌ Don’t:

Ask for permission on first app launch
Send generic messages (“Check out our app!”)
Spam multiple pushes per hour
Send promotional pushes at 3am
Ignore user preferences

Email (When Implemented)

✅ Do:

Use responsive design (mobile-first)
Include plain-text version (accessibility + spam filters)
Test subject lines (A/B test 2-3 variants)
Personalize beyond “Hi ”
Include unsubscribe link (legal requirement)

❌ Don’t:

Use “no-reply@” sender address
Embed only images (triggers spam filters)
Send from inconsistent sender names
Forget mobile optimization
Ignore bounce rates (clean list regularly)

SMS (When Implemented)

✅ Do:

Get explicit opt-in (double opt-in recommended)
Include brand name in message
Provide opt-out instructions (reply STOP)
Keep under 160 characters
Use for high-value, time-sensitive messages

❌ Don’t:

Send without explicit consent
Use URL shorteners (looks spammy)
Send at night (respects quiet hours even more than push)
Forget to register shortcode/long code
Ignore opt-outs (legal violation)

Implementation Status Summary

Opt-out fields currently stored on every user profile:

Channel	Field	Default
Email	`email_opt_out` / `email_opt_out_at`	`UNKNOWN`
SMS	`sms_opt_out` / `sms_opt_out_at`	`NOT_OPTED_OUT`
WhatsApp	`whatsapp_opt_out` / `whatsapp_opt_out_at`	`NOT_OPTED_OUT`
RCS	`rcs_opt_out` / `rcs_opt_out_at`	`NOT_OPTED_OUT`
Push	`push_opt_out` / `push_opt_out_at`	`NOT_OPTED_OUT`

Delivery currently available:

✅ Push Notifications (mobile — iOS/Android)

Delivery planned:

⏳ Email (planned Q3 2026)
⏳ SMS (planned Q4 2026)
⏳ WhatsApp (2027)
⏳ RCS (2027)
⏳ In-App Messages (2027)
⏳ Web Push (2027)

Next: How users manage their communication preferences → User Preferences & Consent

​What are Communication Channels?

​The Simple Definition

​Why Multiple Channels Matter

​How Channels Work Together

​Channel Characteristics to Consider

​Choosing the Right Channel

​Available Channels

​Channel Opt-Out Model

​1. Push Notifications ✅ IMPLEMENTED

​2. Email

​3. SMS

​4. In-App Messages

​5. WhatsApp

​6. RCS (Rich Communication Services)

​7. Web Push

​Channel Selection Matrix

​Multi-Channel Orchestration

​Sequential Delivery

​Preference-Based Routing

​Channel Suppression

​Performance Benchmarks

​Industry Averages (2026)

​Cost Comparison

​Channel-Specific Best Practices

​Push Notifications

​Email (When Implemented)

​SMS (When Implemented)

​Implementation Status Summary

What are Communication Channels?

The Simple Definition

Why Multiple Channels Matter

How Channels Work Together

Channel Characteristics to Consider

Choosing the Right Channel

Available Channels

Channel Opt-Out Model

1. Push Notifications ✅ IMPLEMENTED

2. Email

3. SMS

4. In-App Messages

5. WhatsApp

6. RCS (Rich Communication Services)

7. Web Push

Channel Selection Matrix

Multi-Channel Orchestration

Sequential Delivery

Preference-Based Routing

Channel Suppression

Performance Benchmarks

Industry Averages (2026)

Cost Comparison

Channel-Specific Best Practices

Push Notifications

Email (When Implemented)

SMS (When Implemented)

Implementation Status Summary