name: Nylas description: >- Vocabulary of the terms and objects used across the Nylas v3 platform: authentication and grants, email, calendar, contacts, scheduling, notetaking and notifications. Transcribed from the glossary Nylas maintains in the developer.nylas.com repository, which is the same source that drives automatic term linking throughout the published documentation. version: '1.0' created: '2026-08-20' modified: '2026-08-20' method: provider-published authored_by: Nylas source: https://developer.nylas.com/docs/dev-guide/glossary/ tags: - Calendar - Communication - Contacts - Email - Messaging - Scheduling - Notetaker terms: - term: Access token definition: >- A short-lived token associated with a specific grant or connected account. An application uses an access token to authenticate with the service provider and make data requests on your behalf. In OAuth 2.0 and later, access tokens expire after one hour and can be refreshed. category: Authentication - term: Agent Account definition: >- A fully Nylas-hosted email and calendar mailbox that you create and control entirely through the Nylas API — no OAuth flow required. An Agent Account is exposed through a standard grant and works with every grant-scoped endpoint, but the underlying mailbox lives on Nylas infrastructure rather than on an external provider like Google or Microsoft. Created via POST /v3/connect/custom with "provider": "nylas". category: Core Object - term: API key definition: >- A unique identifier that an application uses to authenticate with the Nylas API. You can find your API key in the Nylas Dashboard. category: Authentication - term: Application definition: >- Refers to one of three concepts in the Nylas docs: the "provider auth application" used to connect to your authentication provider, the Nylas application which contains connections to your project and your connectors, and sometimes "your application" which refers to your actual code project for the application you're working on. For clarity, we may call it "your project" instead. category: Core Object - term: Authentication definition: >- The process of proving who you are, and that you have the right to make decisions about an account and its data. This is different from the _authorization_ header that you use in API requests to pass a token or other credential. The token is like a backstage pass: it _authorizes_ you to make requests. Different types of API authorization headers are known as "authentication" types. Both of these are sometimes shortened to "auth". category: Authentication - term: Authentication token definition: >- A short-lived token that the user receives from the authentication system (the OAuth provider or IDP) which proves that they successfully authenticated (provided account credentials and passed any confirmation steps). The application uses this to retrieve an access token. Unlike an access token, you _cannot_ use authentication tokens to make requests on a user's behalf, or access data. category: Authentication - term: Authorization definition: >- The process of deciding whether you have the right to do something. This is different from "authentication", which is the process of proving who you are, and that you have the right to make decisions about an account and its data. When you make API requests, you use an authorization header to to pass a token or other credential. The token is like a backstage pass: it _authorizes_ you to make requests. Different types of API authorization headers are known as "authentication" types. Both of these are sometimes shortened to "auth". category: Authentication - term: Bounced message definition: >- An automated notification that the email provider sends to let you know that a message you sent wasn't delivered. A message might not be delivered for many reasons, including an incorrect recipient email address. category: Email - term: Bring Your Own (BYO) Authentication definition: >- An authentication flow that we previously called "Custom Authentication". You provide the OAuth refresh token for the user, and Nylas uses it to create a grant and request access tokens as needed to access the user's data. category: Authentication - term: CalDav definition: >- A protocol for working with calendar and schedule information on a remote server. It uses the iCalendar data format, and is used by iCloud and Google Calendar. category: Protocol or Format - term: Callback URI definition: >- The URI that the OAuth provider sends a user back to after they authenticate using Hosted OAuth. You must define this in your Nylas application's settings. This is _similar_ to the Nylas auth "redirect URI", which you specify in your provider auth app. category: Authentication - term: Client-side definition: >- Any code that runs in the user's browser or device, as opposed to server-side code which runs on a server. Client-side code is often written in JavaScript, and is used to create interactive web pages. Client-side applications require special security considerations for secrets management, such as PKCE verification. category: Platform - term: Client ID definition: >- A unique identifier for your Nylas application, used to identify your application when it connects to the Nylas API. You can find your client ID in the Nylas Dashboard. category: Authentication - term: Connector definition: >- A data structure that stores information about how your Nylas application connects to a third-party service provider, such as an email provider, calendar provider, or other data source. Connectors are sometimes called "integrations" or "channels", and might include another term that describes what the connector does (for example, an "auth connector" or a "notification connector"). category: Authentication - term: CRUD definition: >- An acronym for "Create, Read, Update, Delete". These are the four basic operations that you can perform on data. category: Protocol or Format - term: Data center definition: >- Nylas offers two data center options — U.S. and E.U. — to accommodate customers around the world. See the Data residency documentation for more details. category: Platform - term: GCP definition: >- An acronym for "Google Cloud Platform". This is the portal where you create a provider auth app to allow your project to connect to Google resources. category: Platform - term: GDPR definition: >- "General Data Protection Regulation". Regulation set by the European Union, designed to harmonize data privacy laws across Europe. See What is the GDPR?. category: Compliance - term: Grant definition: >- A record of permissions ("scopes") that a user "granted" to your application to access their data. Nylas creates a grant when a user successfully authenticates, and generates an access token. category: Core Object - term: ICS definition: >- "Internet Calendar Scheduling". This is the file format behind iCalendar and CalDav, used by Apple and Google. Each ICS file represents an individual event on a calendar. category: Protocol or Format - term: IMAP definition: >- "Internet Message Access Protocol". This is a protocol for receiving email that allows users to access their messages from different devices. category: Protocol or Format - term: Integration definition: >- An external service connected to your Nylas application. This could be an authentication provider, data source, or another tool like Zoom Meetings. In most cases, these are now called "connectors". category: Provider - term: LLM definition: >- "Large Language Model". A model of artificial intelligence that can complete natural language processing tasks. Nylas uses LLMs to power various features, including the Clean Message endpoint. category: Platform - term: MIME definition: >- "Multipurpose Internet Mail Extensions". An internet standard that allows messages to support attachments and non-ASCII text. category: Protocol or Format - term: Nylas Service Account definition: >- An organization-level authentication mechanism that uses RSA cryptographic request signing to access Nylas admin APIs, such as the Manage Domains API and the Manage API Keys API. This is different from Google or Microsoft "Service Accounts", which are used for bulk authentication grants. category: Core Object - term: OAuth definition: >- An authentication protocol that allows you to approve one application interacting with another on your behalf, without providing your password. See the OAuth specification website for more information. category: Authentication - term: Owner definition: The person who creates and schedules a specific calendar event. category: Scheduling - term: Participant definition: >- A person who is invited to a calendar event. Each event might have more than one participant. category: Scheduling - term: PKCE definition: >- "Proof Key for Code Exchange". A shared secret used in OAuth 2.0 as an additional layer of validation to ensure that the authorization code exchange is secure. This is especially important for client-side applications. category: Authentication - term: Provider definition: See service provider. category: Provider - term: Provider application definition: See provider auth application. category: Core Object - term: Provider auth application definition: >- Sometimes called a "provider integration application" or "provider application". An application that connects the service provider's infrastructure and your Nylas application. category: Core Object - term: Provider integration application definition: See provider auth application. category: Core Object - term: Redirect URI definition: >- The URL that the OAuth provider directs a user to after they authenticate. This URI needs to be registered with the OAuth provider through your provider auth app, and must match the URI that the user is directed to after they authenticate. These are _similar_ to the "callback URI" that you specify in your Nylas application. category: Authentication - term: Refresh token definition: >- A long-lived token that you can use to request new access tokens when they expire. Used to keep users authenticated without requiring them to log in again. category: Authentication - term: Scopes definition: >- Permissions which determine what data your application can access on a specific provider. Your users approve your requested scopes when they authenticate with your application. Scopes must be included in either the connector for the provider, or in the OAuth request. category: Authentication - term: Server-side definition: >- Any code that runs on a server and handles requests from client-side code. Often written in languages like Python, Ruby, or Node.js. category: Platform - term: Service provider definition: >- The company that maintains the email systems, and sometimes the calendaring and contacts tools, which you connect to using Nylas. Sometimes called an "email service provider" or "ESP", or just "provider". category: Provider - term: SLA definition: >- "Service level agreement". An agreement between a provider and their customers, outlining the services that the provider delivers, and the responsiveness the provider adheres to (for example, promising 99% uptime). category: Platform - term: SMTP definition: >- "Simple Mail Transfer Protocol". The underlying protocol used by IMAP providers to _send_ messages from email clients to servers, and back. Technically, all IMAP providers are also SMTP providers. category: Protocol or Format - term: SSE definition: >- "Server-sent events". A push technology that allows your project to receive automatic updates from Nylas. Used in the Smart Compose endpoints to provide AI responses without requiring your application to constantly poll for new information. category: Notifications - term: Time slots definition: >- Periods of time returned by the Calendar API's Availability endpoint, when Nylas has determined that a user is available to meet. These can include additional constraints such as buffer time, a time interval, and other options that you might have specified. category: Scheduling - term: Unix epoch definition: >- The Unix epoch (also known as "epoch time") refers to the specific point in time when the Unix operating system's timekeeping began. This point in time is 00:00:00 UTC on January 1, 1970. category: Protocol or Format - term: Unix timestamp definition: >- The number of seconds that have elapsed since the Unix epoch. Nylas expects time values as Unix timestamps. category: Protocol or Format - term: Useragent definition: >- A string that identifies the application (browser) that the user is using to access the web. This can be useful along with their IP address for identifying traffic from the same person. Nylas doesn't maintain a list of useragents, but you can find a list of common useragents online. category: Protocol or Format - term: Webhook challenge definition: >- When you create or activate a webhook endpoint, Nylas verifies that the endpoint is working by making a GET request to it with a challenge query parameter. Your application must return the _exact value_ of the challenge in the response body within 10 seconds. category: Notifications - term: Webhook endpoint definition: >- The URL that Nylas sends webhook payloads to when an event occurs on the provider. Sometimes called a "webhook receiver" or "webhook URL". category: Notifications - term: Webhook payload definition: >- The data or message that Nylas sends to your webhook endpoint when an event occurs on the provider. category: Notifications - term: Webhook signature definition: >- Included in webhook payloads sent from Nylas. These allow you to verify that the webhook data really did originate from Nylas. category: Notifications - term: Whitelabeling definition: >- The process of customizing the appearance of the Nylas authentication screen and authentication domains to use your company's domain and logo or branding. Basic logo customization is available for all Nylas applications, regardless of plan tier. Additional whitelabeling features are available as an add on to paid plans. category: Authentication