Channels: The Intelligent Abstraction Layer
Channels in Sent represent an intelligent abstraction layer that fundamentally changes how applications approach messaging. Rather than forcing developers to manage multiple messaging platforms, channels provide a unified interface that automatically handles routing, adaptation, and optimization across diverse communication pathways. This architecture treats channels as implementation details rather than primary interfaces, enabling intent-based messaging that optimizes delivery and engagement.
The Channel Architecture
The Sent channel architecture is designed to be flexible and extensible.
Intent-Based Messaging Over Channel Selection
Most messaging platforms expose channels as separate APIs with distinct interfaces and content formats, placing the burden of channel management on developers. Sent inverts this model through intent-based messaging: instead of choosing a channel, you express intent—send a notification, deliver an authentication code, or engage a customer. The system interprets this intent and determines the optimal delivery path.
// Single API call, intelligent routing
await sendMessage({
phoneNumber: "+1234567890",
templateId: "welcome_message",
templateVariables: {
name: "John Doe"
}
});Sent automatically discovers available channels, selects optimal route, and adapts content format
This approach provides a unified developer experience where a single API call can result in SMS delivery in one region, WhatsApp in another, with automatic content adaptation and fallback handling managed transparently.
The Two-Layer Channel Model
Sent's channel architecture operates on two complementary layers:
SMS - The Universal Foundation
- Works on every mobile device with cellular connectivity
- Provides the reliability guarantee through carrier infrastructure
- Serves as the automatic fallback when other channels fail
- Defines the baseline capabilities all templates must support
WhatsApp - The Rich Engagement Layer
- Delivers interactive experiences with media, buttons, and branding
- Enables conversation-based interactions and customer service
- Provides engagement analytics and read receipt data
- Functions as progressive enhancement over the SMS foundation
This architecture ensures universal reach through SMS while enabling rich experiences through WhatsApp, with intelligent routing determining the optimal path for each message.
Progressive Enhancement
Channels, by relying on templates, are designed using progressive enhancement principles (content adapted to the capabilities of the channel):
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Universal Compatibility: Every message starts with content that works on SMS—the most constrained channel—ensuring universal deliverability.
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Automatic Enrichment: When delivered through WhatsApp, the same template automatically gains interactive buttons, media headers, branded business profiles, and rich formatting.
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Graceful Degradation: Complex WhatsApp templates automatically simplify for SMS delivery, preserving essential information and functionality.
Content Adaptation Examples
| Message Type | SMS | |
|---|---|---|
| Authentication | "Your verification code is 123456" | Rich template with branding, verification code, security tips, and interactive "Got it" button |
| Order Update | "Order #12345 shipped. Track: [link]" | Rich card with product image, detailed status, tracking button, and customer service contact |
Channel Intelligence
Sent channels are not just static endpoints—they are dynamic, intelligent, and fully discoverable. Every supported channel (such as SMS, WhatsApp, or future integrations) is deeply integrated to expose its current status, features, and capabilities in real time.
This intelligence allows Sent to always select the best possible channel for each recipient and message, adapting immediately as circumstances change—if a user registers for WhatsApp after previously only having SMS, future messages can automatically upgrade in experience. The discoverable nature of channels also enables transparent monitoring, reporting, and adaptation to new carrier or provider policies, ensuring optimal deliverability and compliance without developer intervention.
Real-Time Availability Detection
When a contact is first encountered, Sent performs comprehensive channel discovery:
Multi-Provider Validation: The system simultaneously queries multiple channel providers—checking carrier data for SMS capability while validating WhatsApp registration status through Meta's APIs.
Capability Assessment: Each provider returns detailed information about supported features (media types, interactive elements, character limits), not just availability.
Engagement Signal Intelligence: Sent leverages a variety of creative signals and data points—such as profile picture presence, last online status, historical engagement patterns, and local channel preferences—to assess user activity and channel suitability. By analyzing these indicators, the platform intelligently prioritizes channels and tailors messaging experiences, ensuring that messages are delivered to users on channels they use most.
Contextual Routing Logic
Channel selection employs sophisticated decision-making that goes beyond availability:
Geographic Optimization: Regional messaging preferences and regulatory requirements automatically inform routing decisions, with compliance handled transparently.
Content-Channel Matching: Rich media content routes to channels that support it, while text-only messages may prefer channels with higher deliverability rates.
Engagement-Based Selection: Active usage indicators inform channel preference decisions, prioritizing channels where users are more likely to engage.
Cost Optimization: Selects the most cost-effective route based on regional pricing, provider rates, and conversation window rules—minimizing spend without sacrificing deliverability or compliance.
Intelligent Fallback: When primary channels fail, the system automatically attempts alternative routes, with SMS serving as the ultimate fallback guarantee.
Technical Implementation
Character Limit Management: Rich templates compress automatically to fit SMS constraints while preserving essential information and call-to-action elements.
Media Handling: Images and videos convert to descriptive text with links for SMS, while delivering full media experiences through WhatsApp.
Interactive Element Conversion: Buttons and quick replies become text alternatives with URL links for SMS, while maintaining full interactivity on WhatsApp.
Channel Infrastructure
Template System Integration: Sent automatically manages Meta's template approval process, submitting new templates and tracking approval status without requiring developer intervention in Meta's platform.
Business Verification: WhatsApp Business accounts display verification badges and professional profiles that build user trust and engagement rates compared to SMS from unknown numbers.
SMS
Carrier Network Integration: Leverages aggregator and carrier agnostic SMS integration for real-time phone number validation, SMS capability assessment, and optimized routing through carrier networks.
Regulatory Compliance: Automatically handles regional SMS requirements, carrier filtering, spam prevention, and opt-out management across different countries and regulations.
Economic Predictability: Straightforward per-message pricing model makes cost calculation and customer billing transparent, with international delivery optimized through carrier relationships.
Channels for Developers
Reduced Complexity: Work with business intent rather than channel-specific implementation details, with routing decisions made using comprehensive intelligence.
Automatic Optimization: Message delivery is optimized across diverse technical environments without requiring platform expertise or complex fallback logic.
Future-Proof Architecture: New channels integrate transparently through the pluggable provider pattern, with existing code automatically benefiting from expanded capabilities.
Channels for Businesses
Higher Delivery Rates: Intelligent routing and SMS fallback ensure messages reach recipients even when primary channels fail, with universal compatibility guaranteeing reachability.
Improved Engagement: Content optimization and intelligent channel selection increase user interaction likelihood, with WhatsApp's rich features enhancing engagement for active users.
Scalable Growth: Expansion into new markets is supported by automatic regional optimization and channel adaptation, with compliance requirements handled transparently.
The channel abstraction means you don't need to manage fallback logic, regional preferences, or platform-specific implementations. Sent's intelligence layer handles these complexities automatically, letting you focus on creating great user experiences.