A
API Key - A secret token used to authenticate requests to Courier’s REST API. Each environment has its own API keys, and keys can be scoped to specific permissions. Audience - A dynamic user collection that automatically updates based on filter rules. Unlike static lists, audiences automatically include or exclude users as their profile data changes. Automation - A multi-step workflow that orchestrates complex messaging sequences with conditional logic, delays, digests, and multiple notification steps.B
Batching - Grouping multiple automation triggers into a single consolidated action within an automation step. Brand - A visual template that applies consistent styling to email notifications, including logos, colors, and layout. Bulk Send - Sending the same notification to many recipients in a single API call using a job-based workflow.C
Channel - A communication method like email, SMS, push notifications, in-app inbox, or direct messaging (Slack, Discord, etc.). Channel Priority - The order in which different communication channels are attempted when delivering a notification. Client Key - A publishable key used to authenticate client-side SDKs (Inbox, Toast, React components). Unlike API keys, client keys are safe to expose in frontend code. Conditions - Logic that enables or disables content blocks, channels, or entire notifications based on user data or other criteria. Content Block - A reusable, responsive content component (text, image, action button, etc.) used inside notification templates in the Template Designer. Courier Create - An embeddable notification designer that lets your users create and edit notification templates within your application.D
Delay - A pause step in automations that waits a specified duration or until a specific time before continuing. Delivery - The final step where a message reaches the recipient through a provider. Designer - Courier’s visual editor for creating and editing notification templates. Device Token - A unique identifier for app-device combinations issued by Apple (APNs) or Google (FCM) push notification gateways. Stored in user profiles. Digest - A feature that batches multiple notifications into a single consolidated message, reducing notification fatigue. Draft / Published - The two states of a notification template. Draft changes are only visible in the test environment until you publish them to production.E
Elemental - A JSON-based syntax for describing notification content programmatically that works across all channels. Environment - Separate instances (test and production) within a workspace that allow safe development without affecting live notifications. Event - A trigger identifier that initiates notifications. Can be a direct notification template ID or a custom event ID mapped to any template via Event Mapping.F
Failover - Automatic switching to backup providers when a primary provider fails to deliver. Feed - A filtered stream of messages in the Inbox component. Feeds let you organize messages into categories like “Notifications” and “Comments” using tabs.G
Guardrails - Safety features like send limits that prevent accidental sends to large audiences or excessive notifications to individual users.H
Handlebars - A templating language used in the Template Designer for dynamic content insertion, conditionals, and loops. See also Handlebars Helpers.I
Idempotency Key - A unique identifier sent with API requests to prevent duplicate processing. If the same key is sent twice, Courier returns the original response. Inbox - Courier’s built-in in-app notification center component for web and mobile applications. Inline Content - Notification content defined directly in the Send API request body rather than referencing a stored template. Integration - A connection between Courier and a notification provider (SendGrid, Twilio, etc.) that handles actual message delivery.J
Jsonnet - A data templating language used in content blocks and the webhook designer for advanced data transformation. JWT (JSON Web Token) - A secure token used for client-side authentication, required for Inbox and other frontend SDK components.L
List - A static group of users that must be manually managed, unlike audiences which update automatically. Locale - A language or regional variant (e.g.,en-US, fr-FR) used for localizing notification content.
Logs - A timeline of sent messages with delivery status, provider responses, and rendered content.
M
MCP (Model Context Protocol) - A protocol that lets AI agents interact with Courier programmatically. Message - A single instance of a notification sent to a specific recipient. Message Status - The delivery state of a message as it moves through the pipeline: enqueued, sent, delivered, opened, clicked, or undeliverable.N
Notification - A message template that can be sent repeatedly through one or more channels, containing variables for personalization.O
Override - A way to modify the request body or configuration sent to a provider, useful for passing provider-specific options not exposed in the template designer. Outbound Webhook - A webhook that Courier fires when specific events occur (message sent, delivered, etc.), allowing you to sync delivery data to external systems.P
Preferences - User-controlled settings that determine which notifications they receive and through which channels. Profile - A JSON object storing a user’s contact information, device tokens, and custom attributes. Provider - The downstream service (Twilio, SendGrid, etc.) that delivers notifications to recipients.R
Recipient - The end user who receives notifications, identified by their profile. Routing - The logic that determines which channels and providers are used to deliver notifications.S
Send Conditions - Rules evaluated at send time that determine whether a notification should be delivered based on data or logic. Send Limit - A cap on how many notifications can be sent to a user, topic, or tenant within a time period. Different from API rate limits. Subscription Topic - A category of notifications (e.g., “Marketing”, “Order Updates”) that users can opt in or out of through preferences. Configured in the Preferences Editor.T
Template - A reusable message design created in the Template Designer that defines content structure and can be sent to multiple recipients. Template Approval - A workflow requiring review before templates can be published to production. Tenant - An organization or customer group in multi-tenant applications, allowing you to scope branding, preferences, and data to specific organizations. Throttle - An automation step that limits how frequently a notification can be triggered for a given scope (per-user, global, or dynamic key). Toast - A transient pop-up notification shown by the Inbox SDK components when a new message arrives. Trigger - An action or event that starts an automation or sends a notification.V
Variable - A placeholder in notification templates (like{name} or {order_id}) that gets replaced with actual data when sending.