Glossary of Sent Messaging, Compliance, and API Terms

Definitions of key terms and concepts used throughout the Sent platform and documentation.

10-Digit Long Code, the registration framework required for A2P (Application-to-Person) SMS messaging in the United States. Businesses sending automated SMS to US numbers must register a brand and campaign with The Campaign Registry (TCR); Sent submits this registration on your behalf when you complete compliance onboarding.

A

API Key

Authentication token passed in the x-api-key header on every API request. Keys prefixed sk_live_ are production keys; keys prefixed sk_test_ are sandbox keys.

Authentication Message

WhatsApp message category for OTP codes, verification messages, and login confirmations. Usually has the lowest cost per message.

Available Channels

Comma-separated list of messaging channels (for example, "sms,whatsapp,rcs") that can reach a specific contact based on their phone number validation.

B

Balance

Account credit used to pay for messages. When a send exceeds the available balance, the API still accepts the request and the message is finalized with the BLOCKED status.

Brand

The business identity registered with The Campaign Registry for 10DLC compliance, grouping contact, business, and compliance (KYC) information. Each Sender Profile has a brand, created with the profile or inherited from the organization.

Branded Sender (RCS)

The visual identity displayed in the recipient's messaging app for RCS messages, including company logo, verified business name, and a checkmark. Unlike SMS, which shows a raw phone number, RCS branded sender makes the business immediately recognizable.

Business Account

WhatsApp Business Account (WABA) identifier required for WhatsApp messaging integration.

C

Campaign

A registered 10DLC messaging use case linked to a brand. A campaign declares one or more use cases with sample messages, plus opt-in, opt-out, and help keywords and compliance links. Campaigns are managed per Sender Profile through the /v3/profiles/{profileId}/campaigns endpoints.

Carousel Card (RCS)

An RCS-standard message format consisting of up to 10 rich cards that the recipient can scroll through horizontally. The 10-card cap is set by the RCS/RBM platform specification, not by Sent. Sent does not currently send carousel messages.

Channel

Communication method used to deliver messages:

SMS: Traditional text messaging
WhatsApp: Business messaging via Meta's WhatsApp Business API
RCS: Rich Communication Services, carrier-native rich messaging for Android (Google Messages), no separate app required

A contact's permission to receive your messages, tracked per contact through the opt_out field. See Opt-Out.

Contact

A phone number recipient in your messaging system, including validation data, available channels, and formatting information.

Contact ID

Unique UUID identifier for a contact within a customer's account.

Customer

The account entity that owns an API key. Depending on account type, a customer is an organization (has child Sender Profiles), a standalone user account, or a Sender Profile; GET /v3/me returns the account associated with your key. Rate limits and idempotency keys are scoped per customer.

Customer ID

Unique UUID identifier for a customer account.

D

Default Channel

Preferred messaging channel for a contact, determined by phone number validation and regional settings.

E

E.164 Format

International phone number standard (for example, +1234567890) used as the canonical format throughout the platform.

Endpoint

API route handling a specific operation (for example, POST /v3/messages, GET /v3/contacts/{id}).

F

Formatting

Phone number representations in various formats:

E.164: +1234567890 (canonical)
International: +1 234-567-890 (human-readable)
National: (234) 567-890 (country-specific)
RFC 3966: tel:+1-234-567-890 (URI format)

I

Idempotency Key

Optional Idempotency-Key header accepted by POST, PUT, and PATCH requests to guarantee at-most-once execution. A key is 1–255 alphanumeric characters, hyphens, or underscores; duplicate requests with the same key return the original response. Keys are scoped per customer and responses are cached for 24 hours.

K

KYC (Know Your Customer)

Compliance data including business information, contact details, and use case descriptions required for messaging services. Collected as part of brand registration.

M

Marketing Message

WhatsApp message category for promotional content and campaigns. Typically has higher cost per message and requires opt-in.

Message Activity

Event log recording a message's processing steps, including channel selection, sending status, and delivery confirmation. Available via GET /v3/messages/{id}/activities.

Message Body

Final rendered content of a message after template variable substitution.

Message Status

The current state of a message, also called delivery status. Outbound statuses are QUEUED, ROUTED, SENT, DELIVERED, READ (WhatsApp and RCS only), FAILED, SCHEDULED (deferred until the recipient's quiet hours end), FILTERED (suppressed by a policy gate such as an opt-out or a routing deny rule), and BLOCKED (gated by an account precondition such as insufficient balance). Inbound messages have the status RECEIVED.

O

Opt-Out

A contact's withdrawal of consent to receive messages. Opt-out is per contact, not per channel, and is exposed as the opt_out field on the contact. Contacts opt out by replying with keywords such as STOP (START opts back in, HELP requests assistance). Sends to opted-out recipients are accepted by the API but suppressed and finalized with the FILTERED status.

Organization

The top-level account in Sent's multi-tenancy model. An organization owns billing, compliance, and shared resources, and contains one or more Sender Profiles that can inherit those resources. Organization API keys can act on behalf of a child profile by passing the x-profile-id header.

P

Pagination

Structure of list responses. Paginated endpoints accept the page query parameter (1-indexed, default 1) and the page_size query parameter (default 20, range 1–100), and return a pagination object with page, page_size, total_count, total_pages, has_more, and optional cursors (after, before).

Phone Number Validation

Process determining if a phone number is valid, possible, and identifying its type (mobile, fixed-line, etc.).

Pricing

Cost structure for messages varying by channel, region, and message category (especially for WhatsApp).

R

RCS (Rich Communication Services)

A carrier-native messaging protocol that enables rich media, interactive buttons, and branded Sender Profiles delivered over carrier networks directly within the Android default messaging app (Google Messages). RCS requires no separate app installation by the recipient. Like WhatsApp, RCS requires account verification, a Sender Profile, and template approval before sending. Sent automatically falls back to SMS for recipients where RCS is unavailable. API channel value: "rcs".

RCS Agent

The branded sender identity used for RCS messaging. Each business has an RCS Agent that displays a company logo, verified business name, and brand color in the recipient's Google Messages inbox, instead of a phone number like SMS. Setting up an RCS Agent requires a one-time approval process with carriers; it cannot be self-activated.

Region Code

ISO 3166-1 alpha-2 country code (for example, "US", "CA") used for pricing and channel availability.

Rich Card (RCS)

An RCS-standard message format that combines a title, description, image or video, and action buttons into a single structured card. Sent does not currently send rich cards; RCS messages sent through Sent render as text with suggestion chips.

S

Sandbox Mode

A request mode that validates a mutation without executing it. Set sandbox: true in the body of any POST, PUT, or DELETE request: authentication and validation run normally, but the request stops before execution, leaving the database, the send queue, and downstream provider APIs untouched. Sandbox responses return realistic sample data and include the X-Sandbox: true header.

Segment

One unit of SMS transmission. A message longer than a single SMS (160 GSM-7 or 70 Unicode characters) is split into segments of up to 153 (GSM-7) or 67 (Unicode) characters that the recipient's phone reassembles into one message. SMS is billed per segment.

Sender ID

The identity displayed as the message sender on the recipient's device. Depending on the destination country, this is an alphanumeric sender ID (for example, MyBrand), a phone number, or a short code. The US and Canada require a numeric sender; alphanumeric sender IDs do not support replies.

Sender Profile

A messaging identity within an organization. Each Sender Profile has its own API credentials, sending identity, and configuration, and can inherit resources (contacts, templates, WhatsApp Business Account, brand, and campaigns) from the organization or keep dedicated ones. Managed via the /v3/profiles endpoints.

SMS

Short Message Service - traditional text messaging.

Suggestion Chip (RCS)

An interactive button displayed below an RCS message that the recipient can tap. Types include quick reply (sends a predefined text back), open URL (launches a browser), and dial number (initiates a call). Suggestion chips are not available on SMS.

System User Access Token

Long-lived access token created in Meta Business Manager for a System User; used to link a WhatsApp Business Account with direct credentials.

T

Template

Reusable message format supporting variable substitution, with a body of up to 1,024 characters:

WhatsApp templates: Must be approved by Meta before use; support rich media and interactive elements
SMS templates: Can be used immediately without approval

Template Category

Classification for message templates:

AUTHENTICATION: OTP and verification messages
MARKETING: Promotional content requiring opt-in
UTILITY: Transactional messages and confirmations

Template Status

Template approval state: PENDING, APPROVED, or REJECTED.

Transaction

Financial record tracking balance changes from message costs, payments, or refunds.

U

Unified Messaging Intelligence

Sent's system for automatically selecting the optimal messaging channel based on contact validation, availability, and cost.

Utility Message

WhatsApp message category for transactional content like order confirmations and delivery notifications.

UUID (Universally Unique Identifier)

128-bit identifier format used for all entity IDs throughout the platform.

V

Validation

Process of verifying phone number format, reachability, and available messaging channels.

Variable Substitution

Process of replacing placeholder values (for example, {{1}}, {{name}}) in message templates with actual content.

W

Webhook

HTTPS endpoint you register to receive real-time event notifications, such as message status changes and inbound messages. Each delivery is a POST request signed with HMAC-SHA256; verify the X-Webhook-Signature header using the endpoint's signing secret before trusting the payload.

WhatsApp Business API

Meta's business messaging platform integrated for professional messaging capabilities.

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