What is the Twilio Messaging API?

TL;DR Twilio's Messaging API enables developers to send and receive SMS, MMS, WhatsApp, and RCS messages at scale. But managing multiple messaging channels and providers gets complex fast. Courier acts as a provider-agnostic orchestration layer that activates messaging across Twilio and other channels from a single platform, giving you the flexibility to route notifications intelligently without vendor lock-in.

In This Article:

• What is the Twilio Messaging API and how does it work?
• How does Courier enhance multi-channel notification delivery?
• Why do modern applications need SMS, WhatsApp, and multi-channel messaging?
• Which messaging channels does Twilio support?
• What are the differences between Twilio's phone number types?
• How do you send messages with the Twilio API?
• Why orchestration layers matter for multi-channel messaging
• Why Twilio chose Courier to be their orchestration platform and in-app solution

What is the Twilio Messaging API and how does it work?

The Twilio Messaging API is a programmable platform that lets you send and receive text messages, images, and videos across multiple communication channels. Think of it as the infrastructure layer that connects your application to global carrier networks, handling the technical complexity of message delivery across 180+ countries.

At its core, Twilio provides a REST API that accepts your message content, recipient information, and sender details, then routes that message through its network of carrier connections. The API handles retry logic, delivery receipts, and conversion tracking, giving you visibility into whether messages were sent, delivered, or failed.

The platform shines when you need to send high-volume transactional messages like order confirmations, shipping updates, or authentication codes. With 193+ billion messages sent annually through Twilio and 99.95% monthly uptime, the infrastructure is battle-tested at scale. However, enterprise notification strategies require more than just reliable SMS delivery. They need orchestration across multiple channels and providers, which is where a platform like Courier becomes essential.

How does Courier enhance multi-channel notification delivery?

Courier acts as a provider-agnostic orchestration layer that sits above messaging providers like Twilio, email services like SendGrid, and push notification platforms like Firebase. Instead of integrating with each provider separately and managing their individual APIs, quirks, and limitations, you integrate once with Courier and gain access to dozens of communication channels.

The platform's orchestration capabilities let you design notification templates that work across any channel, set routing rules that determine which provider to use based on cost or performance, and implement fallback logic when primary channels fail. When Twilio experiences regional delivery issues or you need to implement intelligent routing based on user preferences, Courier automatically handles the complexity.

Courier also provides centralized user preference management, so recipients can control which channels they receive notifications on without you building custom preference centers for each provider. The platform tracks delivery across your entire notification stack, giving you unified analytics rather than forcing you to cobble together data from multiple provider dashboards.

For teams building modern applications, Courier eliminates the technical debt of maintaining multiple provider integrations while giving you the flexibility to add new channels, switch providers, or implement sophisticated routing logic without rewriting code. You get the reliability of best-in-class providers like Twilio combined with the flexibility of true multi-channel orchestration.

Why do modern applications need SMS, WhatsApp, and multi-channel messaging?

Your users aren't on a single channel, so your notifications shouldn't be either. A customer checking email might miss a critical shipping update, but they'll see an SMS within minutes. Someone traveling internationally might have spotty SMS coverage but reliable WhatsApp connectivity. A user who's actively in your app doesn't need an external notification when an in-app message will suffice.

SMS remains the most reliable channel for time-sensitive notifications like authentication codes, delivery updates, and appointment reminders. Unlike email, SMS doesn't get caught in spam filters, and unlike push notifications, it doesn't require your app to be installed. The average SMS open rate exceeds 98%, with most messages read within three minutes of delivery. This makes SMS messaging essential for transactional notifications where immediate visibility matters.

WhatsApp brings a different set of advantages, particularly for international communications and customer support scenarios. In markets like India, Brazil, and Europe, WhatsApp is the primary communication channel, with users checking it more frequently than email or traditional SMS. The platform supports rich media, read receipts, and two-way conversations, making it ideal for order confirmations with tracking links, customer service interactions, and marketing messages in regions where WhatsApp dominates.

But the real power comes from combining channels intelligently. A well-designed notification strategy might send an in-app message first for active users, fall back to push notifications for users with your app installed but not currently active, then escalate to SMS or WhatsApp for critical messages that require immediate attention. Email serves as a persistent record that users can reference later. This multi-channel approach ensures messages reach users through their preferred channels while optimizing costs and respecting their preferences.

The challenge is that each channel requires separate provider integrations, different API structures, and unique compliance requirements. SMS delivery in the US requires 10DLC registration. WhatsApp requires business verification and approved message templates. Managing this complexity across providers is exactly what Courier's channel settings and routing logic handle automatically.

Which messaging channels does Twilio support?

Twilio's messaging capabilities extend beyond basic SMS texting. The platform supports SMS for straightforward text messages that work on any mobile device, MMS for sending images and videos up to 5MB in size, and RCS (Rich Communication Services) for enhanced messaging experiences with read receipts, typing indicators, and rich media on supported Android devices.

The platform also provides WhatsApp messaging integration, which is particularly valuable for international communications where WhatsApp dominates as the preferred messaging channel. WhatsApp Business API through Twilio requires approval and verification but gives you access to 2+ billion users worldwide.

Each channel has different throughput limits, compliance requirements, and best practices. SMS messages through toll-free numbers can handle high volume but require verification for marketing use cases. WhatsApp has strict rules about message templates and opt-in requirements. When you're managing these channels alongside email, push notifications, and in-app messages through other providers, the complexity multiplies quickly.

What are the differences between Twilio's phone number types?

Twilio offers four main types of phone numbers for messaging, each optimized for different use cases and volume requirements. Understanding these differences is critical for deliverability and compliance.

Toll-free numbers use recognizable prefixes like 800, 833, or 855. These 10-digit numbers support both voice calls and text messages, with high throughput for notifications, alerts, and promotional messages. Toll-free numbers require a verification process through Twilio's system, but once approved, they handle volume well and are recognizable to recipients. They work well for automated notifications where you need consistent, high-volume sending without geographic association.

A2P 10DLC (Application-to-Person 10-digit long codes) are local phone numbers with area codes like +1 (415) 568-0012. These numbers are specifically designed for business messaging traffic and require campaign registration with The Campaign Registry. The registration process involves proving your use case, getting your brand verified, and having your message campaigns approved. This overhead exists to reduce spam and improve deliverability, but it adds complexity. Once registered, 10DLC numbers provide good throughput and local presence, which can increase trust and response rates for regional businesses.

Short codes are 5-6 digit numbers like 56748 that support the highest throughput, starting at 100 messages per second. They're ideal for high-volume use cases like appointment reminders or verification codes sent to thousands of users simultaneously. Short codes require a separate application process and take several weeks to provision, but they offer the best deliverability rates for bulk messaging. The trade-off is higher cost and longer setup time compared to other number types.

Alphanumeric sender IDs display your company name instead of a phone number, showing up as something like "YourBrand" in the sender field. These work for one-way messaging in supported countries outside the United States, where carrier restrictions prevent their use. In markets where they're available, alphanumeric sender IDs provide excellent brand recognition without requiring number provisioning.

Navigating these options and compliance requirements takes significant effort. When you factor in managing multiple channels beyond SMS, like email and push notifications through other providers, the operational overhead becomes substantial. This is where orchestration platforms provide value by abstracting provider-specific complexity.

How do you send messages with the Twilio API?

Sending a message through Twilio requires making a POST request to their Messages endpoint with three essential parameters: the recipient's phone number (in E.164 format), your Twilio phone number or messaging service ID, and the message body.

Here's what a basic cURL request looks like:

curl -X POST "https://api.twilio.com/2010-04-01/Accounts/$TWILIO_ACCOUNT_SID/Messages.json" \
  --data-urlencode "From=+15017122661" \
  --data-urlencode "Body=Your verification code is 123456" \
  --data-urlencode "To=+15558675310" \
  -u $TWILIO_ACCOUNT_SID:$TWILIO_AUTH_TOKEN

The response includes a message SID that you use for tracking delivery status. Twilio provides webhooks for status updates, letting you know when messages are queued, sent, delivered, or failed. You configure these webhooks in your Twilio console or via the API, and Twilio will POST status updates to your specified endpoint.

For production applications, you'll want to use one of Twilio's official SDKs for Node.js, Python, Ruby, PHP, Java, C#, or other languages. The SDKs handle authentication, retry logic, and type safety, making integration more reliable than raw HTTP requests. They also provide helpful abstractions for common operations like sending MMS messages with media attachments or managing messaging services.

The direct integration approach works well for simple use cases where you're only sending SMS through Twilio. But as your notification requirements grow to include multiple channels, user preferences, templating systems, and failover logic, you'll find yourself building and maintaining significant infrastructure around Twilio's API. This is where many teams start exploring orchestration layers that can abstract provider complexity while preserving the flexibility to use multiple channels and providers.

Why orchestration layers matter for multi-channel messaging

Direct provider integrations work fine when you're sending basic SMS messages through a single channel. But modern notification strategies require coordinating multiple channels, respecting user preferences, implementing fallback logic, and maintaining consistent branding across touchpoints.

Consider what happens when you need to send a password reset notification. Your preferred approach might be sending an SMS through Twilio, but what if the user's phone number is invalid, they're traveling internationally, or Twilio experiences a regional outage? An orchestration layer lets you implement fallback logic that tries email as a secondary channel, ensuring critical messages reach users regardless of channel availability.

Orchestration also becomes essential for notification sequences. When a user abandons their shopping cart, you might send an in-app message immediately, follow up with push notification after an hour if they don't return, and send an email after 24 hours with a discount code. Managing this logic across multiple provider APIs creates maintenance overhead and increases the risk of inconsistent user experiences.

This is where Courier's mobile channel capabilities shine. Instead of managing phone numbers, email addresses, and device tokens separately for each provider, you send to a user identifier. Courier handles provider routing, retry logic, and preference management automatically. You design notification templates once, configure routing rules at the orchestration level, and let Courier handle the complexity of provider-specific formatting, rate limiting, and delivery tracking.

When you need to add a new provider or switch from Twilio to another SMS service, you update configuration in Courier rather than rewriting integration code. The platform also provides an inbox component for surfacing notifications directly in your application, ensuring important messages reach users even when SMS or email delivery fails. This multi-channel approach significantly improves notification delivery rates and user engagement while reducing the engineering effort required to maintain notification infrastructure.

Why Twilio chose Courier to be their orchestration platform and in-app solution

Following the end of life for Twilio Notify, Twilio needed a partner that could handle in-app notification orchestration and multi-channel coordination at enterprise scale. They chose Courier because the platform provides exactly what their customers needed: a flexible orchestration layer that works seamlessly with Twilio's messaging services while supporting other channels and providers.

Courier integrates with Twilio's SMS and WhatsApp APIs while adding orchestration capabilities that go beyond what any single provider can offer. Teams using Twilio can now implement intelligent routing, manage user preferences across channels, design notification templates that work everywhere, and track delivery across their entire notification stack. The partnership gives developers the best of both worlds: Twilio's reliable messaging infrastructure and Courier's sophisticated orchestration platform.

The integration is continuously improving, with Courier regularly shipping new features and enhancements that benefit Twilio users. Whether you're migrating from Twilio Notify or building notification infrastructure from scratch, Courier provides the tooling you need to deliver messages reliably across every channel your users prefer.

Ready to see how Courier can enhance your notification strategy with Twilio? Request a demo to speak with a solutions engineer about your specific use case.

Frequently Asked Questions

How much does the Twilio Messaging API cost?

Twilio pricing varies by message type and destination country. In the United States, SMS messages typically cost around $0.0079 per message sent through a toll-free number or 10DLC number, while short code messages cost approximately $0.0075 per segment. MMS messages cost more due to media transmission. WhatsApp pricing follows a different model with conversation-based pricing that varies by country and message type (marketing, utility, or authentication). International rates vary significantly by destination. Twilio provides transparent pricing with volume discounts available as you scale. However, when using an orchestration platform like Courier, you can optimize costs by routing messages through the most cost-effective provider for each region or use case.

Can I use Twilio Messaging API without Courier?

Absolutely. Twilio's Messaging API works independently and provides robust functionality for SMS, MMS, WhatsApp, and RCS messaging. Many applications use Twilio directly when their needs are straightforward and limited to messaging channels. However, as notification requirements grow to include email, push notifications, in-app messaging, and sophisticated routing logic, teams often find that managing multiple provider integrations becomes complex. Courier becomes valuable when you need orchestration across multiple channels and providers, user preference management, advanced routing rules, or want to avoid vendor lock-in by maintaining flexibility to switch providers without rewriting code.

What is the difference between Twilio and Courier?

Twilio is a communications infrastructure provider that offers APIs for SMS, WhatsApp, voice, video, and other channels. It excels at delivering messages through carrier networks with high reliability. Courier is a notification orchestration platform that sits above providers like Twilio, SendGrid, Firebase, and others. Instead of integrating with each provider separately, you integrate with Courier once and gain access to multiple channels and providers. Courier handles routing logic, user preferences, fallback chains, template management, and unified analytics across all your notification channels. Think of Twilio as the delivery vehicle and Courier as the smart orchestration layer that decides which vehicle to use, when to use it, and how to handle failures.

How long does it take to set up the Twilio Messaging API?

Setting up Twilio for basic SMS delivery takes about an hour if you have a developer familiar with REST APIs. You'll need to create a Twilio account, purchase a phone number, verify it for messaging, and integrate their API or SDK into your application. However, the setup complexity increases significantly when you factor in compliance requirements like 10DLC registration (which can take several business days for approval) or WhatsApp Business verification (which can take a week or more). Building production-ready infrastructure with templating, user preferences, delivery tracking, and error handling can take weeks. Using Courier's Twilio integration reduces setup time because you configure Twilio once in Courier and immediately gain access to orchestration features without building them yourself.

Does Courier support Twilio WhatsApp messages?

Yes, Courier fully supports Twilio's WhatsApp Business API integration. You can configure Twilio as a WhatsApp provider in Courier and send WhatsApp messages alongside SMS, email, push notifications, and other channels from a single API. Courier handles the complexity of WhatsApp's template requirements, provides a visual designer for creating WhatsApp message templates, and lets you implement fallback logic if WhatsApp delivery fails. This is particularly useful for international applications where you want to route messages to WhatsApp in regions where it's dominant and fall back to SMS in markets where WhatsApp adoption is lower.

What happens if Twilio has an outage or delivery issues?

When you integrate directly with Twilio, an outage means your messages don't get delivered until service is restored. This is one of the key advantages of using an orchestration layer like Courier. With Courier, you can configure multiple SMS providers (Twilio, Vonage, MessageBird, etc.) and set up automatic fallback rules. If Twilio experiences regional delivery issues or an outage, Courier automatically routes messages through your backup provider, ensuring critical notifications still reach users. You can also configure geographic routing to use different providers in different regions, reducing the impact of localized delivery problems. This provider redundancy is particularly important for transactional messages like authentication codes or order confirmations where delivery failures directly impact user experience.

Can I migrate from Twilio Notify to Courier?

Yes, and this is exactly what many Twilio customers are doing following Twilio Notify's end of life. Courier provides similar multi-channel orchestration capabilities with additional flexibility and features that Twilio Notify didn't offer. The migration involves mapping your existing Notify notification templates to Courier templates, configuring your Twilio credentials as a provider in Courier, and updating your send calls to use Courier's API. The advantage is that you're no longer limited to Twilio's ecosystem and can easily add other providers, implement sophisticated routing logic, and use Courier's inbox component for in-app notifications. Courier's solutions team can help with migration planning and implementation if you have complex notification workflows.