Register A2P
Submit an SMS registration. Standard one-time fees are $25 for sole_proprietor or standard_brand and $70 for high_volume. Carrier review and number attachment must complete before outbound SMS is ready. Parent-account requests create a dedicated sub-account by default: save sub_account_id and use X-Sub-Account-Id for that campaign’s agents, numbers, and status. High-volume registration requests vetting; assigned capacity varies. Use PATCH /v1/register to correct an existing submission without another registration fee. See SMS registration for the workflow and troubleshooting.
Authentication
Bearer authentication of the form Bearer <token>, where token is your auth token.
Headers
Request
sole_proprietor ($25) for individuals without an EIN, standard_brand ($25) for EIN businesses with lighter volume, or high_volume ($70) for EIN businesses sending at scale with third-party brand vetting.
Your first name (or business contact’s first name).
Your last name (or business contact’s last name).
Contact phone number in E.164 format (e.g. +15551234567).
US state abbreviation (e.g. CA, NY).
ZIP code (e.g. 94105).
What your business does, who you message, and what types of messages you send. 40-4096 characters.
1-5 specific use cases: customer_care, account_notification, delivery_notification, fraud_alert, higher_education, marketing, polling_voting, public_service_announcement, security_alert, two_factor_authentication.
2-5 example messages you would send. Each 20-1024 chars, include your brand name. Include opt-out language like ‘Reply STOP to unsubscribe’ in at least one.
How users opt in to receive messages. 40-4096 characters.
Publicly accessible HTTPS URL to a screenshot of your opt-in flow (PNG, JPG, WEBP, or GIF, max 2MB). Google Drive sharing links are supported.
Legal/registered business name. Required for standard_brand and high_volume.
Public-facing brand name if different from business_name.
Business structure: sole_proprietor, private_corporation, public_corporation, llc, partnership, non_profit, co_op, government. Required for standard_brand and high_volume.
Your role: ceo, cfo, cto, coo, vp, gm, director, other. Required for standard_brand and high_volume.
Custom title when contact_title is other.
EIN / Tax ID number. Required for standard_brand and high_volume.
Industry category (e.g. technology, real_estate, retail, healthcare).
Regions where the business operates. Defaults to ["usa_and_canada"].
Number of phone numbers you plan to use. Defaults to 1. sole_proprietor campaigns are limited to 1 number.
Expected message volume: low (default) or high.
URL to your privacy policy. Required for standard_brand and high_volume.
URL to your terms of service. Required for standard_brand and high_volume.
Content types in messages: links, phone_numbers, age_gated, direct_lending. Defaults to [].
Create a dedicated sub-account for this campaign. Defaults to true. Set false to register on your main account.