Glossary

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

A

API Key

Authentication token used to access Sent's API endpoints.

API Key: Provides access to all customer data through the x-api-key header

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 (e.g., "sms,whatsapp,rcs") that can reach a specific contact based on their phone number validation.

B

Balance

Customer account credit amount used for message payments. Tracked via CustomerBalance with detailed transaction history.

Business Account

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

C

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

Channel Provider

Service integration handling specific messaging channels (e.g., WhatsappChannelProvider, SmsProvider).

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

Primary entity representing a business account in the Sent platform. Contains messaging configuration, API keys, and channel settings.

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.

Delivery Status

Message state indicating current status: QUEUED, ROUTED, SENT, DELIVERED, READ, or FAILED.

E

E.164 Format

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

Endpoint

API route handling specific operations (e.g., /v2/contacts/id, /v2/messages/phone).

F

FastEndpoints

.NET framework used for building API endpoints with built-in validation and documentation.

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

InstantiatedPhones

Phone numbers available in the system for customer assignment, managed for SMS messaging.

K

KYC (Know Your Customer)

Compliance data including business information, contact details, and use case descriptions required for messaging services.

M

Marketing Message

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

Message Activity

Event tracking for message processing including channel selection, sending status, and delivery confirmation.

Message Body

Final rendered content of a message after template variable substitution.

Message Template

Pre-approved message format for WhatsApp or reusable content for SMS, supporting variable substitution.

Messaging Profile

SMS provider configuration for messaging, containing webhook URLs and delivery settings.

P

Pagination

Result set structure with items, totalCount, page, pageSize, and totalPages for handling large data sets.

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).

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.

Rich Card (RCS)

An RCS message format that combines a title, description, image or video, and action buttons into a single structured card. Rich cards provide a more engaging layout than plain text and are not available on SMS.

Carousel Card (RCS)

An RCS message format consisting of up to 10 rich cards that the recipient can scroll through horizontally. Ideal for product listings, menu options, or multi-step onboarding flows.

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.

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.