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One API Call to Send SMS via Twilio

The Twilio API requires phone number provisioning, A2P 10DLC registration for US messaging, and compliance with carrier filtering rules. RelayAPI handles OAuth, rate limits, media hosting, and API changes.

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POST /v1/posts
const res = await fetch("https:">//api.relayapi.dev/v1/posts", {
  method: "POST",
  headers: {
    Authorization: "Bearer rlay_live_xxxx",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    content: "Check out our latest update!",
    platforms: ["twilio"],
    media: ["https:">//cdn.example.com/image.jpg"],
  }),
});

Twilio API

  • A2P 10DLC registration for US messaging requires brand registration, campaign vetting, and can take days to weeks
  • Phone number provisioning, compliance bundles, and messaging service configuration add significant setup overhead
  • Carrier filtering and deliverability vary by carrier, content type, and sending volume with limited visibility
  • Pricing is complex with per-segment charges, carrier fees, and different rates for domestic vs international messages
  • Handling delivery status callbacks, opt-out management (STOP/START), and error codes requires webhook infrastructure

RelayAPI

  • RelayAPI guides you through A2P 10DLC registration and handles brand/campaign setup for US messaging compliance
  • We manage phone number provisioning, messaging service configuration, and compliance bundles on your behalf
  • Built-in deliverability monitoring with carrier filtering detection, content optimization, and throughput management
  • Transparent pricing with per-message cost estimates and automatic segment optimization to reduce costs
  • We handle delivery callbacks, opt-out compliance (STOP/START), and error recovery so you get clean status updates
Save 3+ hours of development time

A2P 10DLC Registration Required for US Messaging

Sending SMS to US numbers requires A2P 10DLC registration with carrier-verified brand and campaign information. Messages sent without registration may be filtered or blocked by carriers.

Supported content types

SMSMMSWhatsApp via TwilioShort Codes

How it works

1

Connect your account

Authorize your Twilio SMS account via OAuth in about 30 seconds.

2

Build your integration

Use the REST API or our SDKs to publish content from your stack.

3

We handle the rest

RelayAPI manages publishing, rate limits, and delivery notifications.

Ship Faster

Send SMS and MMS with a single API call. No phone number provisioning, no A2P registration management, no webhook infrastructure. Specify the recipient and message, we handle delivery.

Official API, Zero Hassle

RelayAPI uses the official Twilio API. Your messages are delivered through Twilio's global network with full delivery tracking, while we handle compliance, phone numbers, and carrier requirements.

Deliverability Optimization

Carrier filtering is the biggest challenge in SMS. RelayAPI monitors deliverability, detects filtering patterns, optimizes message content, and manages sending throughput to maximize delivery rates.

Frequently asked questions

Do I need my own Twilio account?

You can connect your existing Twilio account or use RelayAPI's managed messaging infrastructure. Both options support full SMS/MMS capabilities with delivery tracking and compliance management.

What message types can I send through RelayAPI?

RelayAPI supports SMS (text-only), MMS (with images, videos, and other media), WhatsApp via Twilio, and short code messaging. International messaging to 180+ countries is supported.

What is A2P 10DLC and do I need it?

A2P 10DLC (Application-to-Person 10-Digit Long Code) is required for sending SMS to US phone numbers from standard phone numbers. It involves registering your brand and campaign with carriers. RelayAPI handles the entire registration process for you.

How does RelayAPI handle opt-out compliance?

TCPA compliance requires honoring STOP/START keywords. RelayAPI automatically manages opt-out lists, processes STOP/START messages, and prevents messaging to opted-out numbers. Compliance is handled without any code on your end.

Can I send international SMS through RelayAPI?

Yes. RelayAPI supports international SMS to 180+ countries through Twilio's global network. We handle country-specific formatting, sender ID requirements, and regulatory compliance for each destination.

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