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openapi: 3.2.0
info:
title: Nylas Application-level templates API
version: v3
summary: The complete Nylas v3 API — Email, Calendar, Contacts, Notetaker, Scheduling, Administration, and Migration.
description: The Nylas API is designed using the REST ideology to provide simple and predictable URIs to access and modify objects.
contact:
url: https://www.nylas.com/
x-provenance:
method: harvested
first_party: true
publisher: Nylas
source: https://developer.nylas.com/_spec-files/nylas-api.yaml
harvested: '2026-08-21'
sha256: 7ff001d571e163b1ffe22178741b59f813d8208ec878157a839a33dc2c13fd35
bytes: 1666223
note: 'Published by Nylas as the unified contract for the Nylas v3 API and stored verbatim; API Evangelist added only this provenance block. Submitted by the provider in api-evangelist/nylas#1 and verified against the live URL before harvest: OpenAPI 3.1.0, 118 paths, 208 operations, 174 component schemas, 100% of operations carrying summary, description, tag and a unique operationId, x-code-samples on 208 of 208. This document REPLACES a 22-operation scaffold API Evangelist derived from reading the documentation, now quarantined under openapi/_scaffold/.'
x-evidence:
- url: https://developer.nylas.com/_spec-files/nylas-api.yaml
what: the published unified contract, harvested verbatim 2026-08-21 (200, text/yaml, 1,666,223 bytes)
- url: https://developer.nylas.com/.well-known/api-catalog
what: RFC 9727 linkset advertising that URL as service-desc for api.us.nylas.com and api.eu.nylas.com (200, application/linkset+json)
servers:
- url: https://api.us.nylas.com
description: U.S.
- url: https://api.eu.nylas.com
description: E.U.
security:
- ACCESS_TOKEN: []
- NYLAS_API_KEY: []
tags:
- name: Application-level templates
description: Application-level templates let you create reusable messages with dynamic content.
paths:
/v3/templates:
get:
summary: Return all templates
tags:
- Application-level templates
operationId: list-app-level-templates
description: Returns a list of application-level templates.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
parameters:
- $ref: '#/components/parameters/limit'
- $ref: '#/components/parameters/page_token'
x-code-samples:
- lang: bash
label: cURL
source: "curl --request GET \\\n --url \"https://api.us.nylas.com/v3/templates\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json'"
responses:
'200':
$ref: '#/components/responses/templates_list'
'400':
description: 'Error: Bad request'
content:
application/json:
schema:
$ref: '#/components/schemas/400-2'
post:
summary: Create a template
tags:
- Application-level templates
operationId: create-app-level-template
description: Creates an application-level template.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
requestBody:
$ref: '#/components/requestBodies/template_create'
x-code-samples:
- lang: bash
label: cURL
source: "curl --request POST \\\n --url \"https://api.us.nylas.com/v3/templates\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json' \\\n --data '{\n \"body\": \"<p>Hello from {{user}}</p>\",\n \"name\": \"Nylas Alias\",\n \"subject\": \"New notification for {{user}}\",\n \"engine\": \"mustache\"\n }'"
responses:
'200':
$ref: '#/components/responses/template'
'400':
$ref: '#/components/responses/template_400'
/v3/templates/{template_id}:
parameters:
- schema:
type: string
name: template_id
in: path
required: true
description: The ID of the template to access.
example: 14c00cc8-648c-4381-ad10-52641d9bac8e
get:
summary: Return a template
tags:
- Application-level templates
operationId: get-app-level-template
description: Returns the specified application-level template.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
x-code-samples:
- lang: bash
label: cURL
source: "curl --request GET \\\n --url \"https://api.us.nylas.com/v3/templates/<TEMPLATE_ID>\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json'"
responses:
'200':
$ref: '#/components/responses/template'
'400':
$ref: '#/components/responses/template_400'
put:
summary: Update a template
tags:
- Application-level templates
operationId: update-app-level-template
description: Updates the specified application-level template.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
requestBody:
$ref: '#/components/requestBodies/template_update'
x-code-samples:
- lang: bash
label: cURL
source: "curl --request PUT \\\n --url \"https://api.us.nylas.com/v3/templates/<TEMPLATE_ID>\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json' \\\n --data '{\n \"body\": \"<p>Test from {{user.name}}</p>\",\n \"name\": \"Update Template\",\n \"subject\": \"Test from {{user.name}}\",\n \"engine\": \"mustache\"\n }'"
responses:
'200':
$ref: '#/components/responses/template'
'400':
$ref: '#/components/responses/template_400'
delete:
summary: Delete a template
tags:
- Application-level templates
operationId: delete-app-level-template
description: Deletes the specified application-level template.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
x-code-samples:
- lang: bash
label: cURL
source: "curl --request DELETE \\\n --url \"https://api.us.nylas.com/v3/templates/<TEMPLATE_ID>\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json'"
responses:
'200':
$ref: '#/components/responses/delete_200_simple'
'400':
$ref: '#/components/responses/400'
/v3/templates/render:
post:
summary: Render template as HTML
tags:
- Application-level templates
operationId: render-template-html
description: 'Renders the HTML content of an application-level template using the provided variables and specified
templating engine.'
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
requestBody:
$ref: '#/components/requestBodies/template_render_html'
x-code-samples:
- lang: bash
label: cURL
source: "curl --request POST \\\n --url \"https://api.us.nylas.com/v3/templates/render\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json' \\\n --data '{\n \"body\": \"<p>Hello from {{user.name}}, test {{ foo }}</p>\",\n \"variables\": {\n \"user\": {\n \"name\": \"Nylas\",\n \"surname\": \"Tester\"\n },\n \"foo\": \"hi\"\n },\n \"engine\": \"mustache\"\n }'"
responses:
'200':
$ref: '#/components/responses/template_render_html'
'400':
description: 'Error: Bad request'
content:
application/json:
schema:
$ref: '#/components/schemas/400-2'
/v3/templates/{template_id}/render:
parameters:
- schema:
type: string
name: template_id
in: path
required: true
description: The ID of the template to access.
example: 14c00cc8-648c-4381-ad10-52641d9bac8e
post:
summary: Render a template
tags:
- Application-level templates
operationId: render-app-level-template
description: Renders the specified application-level template with the provided variables.
x-scopes:
google:
min: ''
microsoft:
min: ''
yahoo:
min: ''
security:
- NYLAS_API_KEY: []
requestBody:
$ref: '#/components/requestBodies/template_render'
x-code-samples:
- lang: bash
label: cURL
source: "curl --request POST \\\n --url \"https://api.us.nylas.com/v3/templates/<TEMPLATE_ID>/render\" \\\n --header 'Accept: application/json' \\\n --header 'Authorization: Bearer <NYLAS_API_KEY>' \\\n --header 'Content-Type: application/json' \\\n --data '{\n \"variables\": {\n \"user\": {\n \"name\": \"Nylas\",\n \"surname\": \"Tester\"\n }\n }\n }'"
responses:
'200':
$ref: '#/components/responses/template_render'
'400':
description: 'Error: Bad request'
content:
application/json:
schema:
$ref: '#/components/schemas/400-2'
components:
responses:
template_render_html:
description: Success. Returns rendered HTML.
content:
application/json:
schema:
type: object
required:
- data
- request_id
properties:
request_id:
type: string
description: The ID of the request.
example: 3907012912-13b5a9a4-f136-4761-a31b-68c6a8af825d
data:
type: object
required:
- body
properties:
body:
type: string
description: The rendered HTML with variables substituted.
example: <p>Hello Leyah, your booking has been confirmed.</p>
template:
description: Success. Returns template.
content:
application/json:
schema:
type: object
required:
- data
- request_id
properties:
request_id:
type: string
description: The ID of the request.
data:
$ref: '#/components/schemas/template'
example:
request_id: 3822087561-67d4f28f-a46b-4c90-8fd3-765a04105043
data:
id: 14c00cc8-648c-4381-ad10-52641d9bac8e
grant_id: 6c45fe5e-0bb6-41b9-9acc-ccb15bfc51eb
app_id: null
engine: mustache
name: Booking confirmed message
subject: '{{user.name}}, your booking is confirmed!'
body: <p>Hello {{user.name}}, your booking has been confirmed.</p>
created_at: 1640995200
updated_at: 1640995200
object: template
template_render:
description: Success. Returns rendered template.
content:
application/json:
schema:
type: object
required:
- data
- request_id
properties:
request_id:
type: string
description: The ID of the request.
example: 3822450015-47d9207c-4d06-4e15-b3e7-752c5dd5585d
data:
type: object
required:
- body
- subject
properties:
body:
type: string
description: The rendered HTML body content with variables substituted.
example: <p>Hello Leyah, your booking has been confirmed.</p>
subject:
type: string
description: The rendered subject content with variables substituted.
example: Leyah, your booking is confirmed!
templates_list:
description: Success. Returns list of templates.
content:
application/json:
schema:
type: object
required:
- data
- next_cursor
- request_id
properties:
request_id:
type: string
description: The ID of the request.
example: 3821703913-a3548169-0de0-49de-9801-37d972b51766
data:
type: array
items:
$ref: '#/components/schemas/template'
example:
- id: template_123
grant_id: grant_456
app_id: null
engine: mustache
name: Welcome Email
subject: Welcome {{user.name}}!
body: <p>Hello {{user.name}}, welcome to our service!</p><p>We're excited to have you on board.</p>
created_at: 1640995200
updated_at: 1640995200
object: template
- id: template_456
grant_id: grant_456
app_id: null
engine: handlebars
name: Password Reset
subject: Reset your password - {{company.name}}
body: <h1>Password Reset Request</h1><p>Hi {{user.name}},</p><p>Click <a href='{{reset_link}}'>here</a> to reset your password.</p><p>This link expires in {{expiry_hours}} hours.</p>
created_at: 1640995300
updated_at: 1640995400
object: template
- id: template_789
grant_id: grant_456
app_id: null
engine: twig
name: Order Confirmation
subject: 'Order #{{order.number}} confirmed'
body: '<h2>Thank you for your order!</h2><p>Order #{{order.number}} has been confirmed.</p><ul>{% for item in order.items %}<li>{{item.name}} - ${{item.price}}</li>{% endfor %}</ul><p>Total: ${{order.total}}</p>'
created_at: 1640995500
updated_at: 1640995500
object: template
next_cursor:
type: string
description: A cursor pointing to the next page of results for the request.
example: eyJjdXJzb3IiOiJ0ZW1wbGF0ZV8xMjMifQ==
delete_200_simple:
description: 'Success: Object deleted'
content:
application/json:
schema:
type: object
required:
- request_id
properties:
request_id:
type: string
description: The ID of the request.
example: 3906564297-48e7fb5b-f220-427b-a4de-255736adba08
template_400:
description: 'Error: Bad request'
content:
application/json:
schema:
type: object
required:
- error
- request_id
properties:
request_id:
type: string
description: The ID of the request.
example: 3704952820-faf9214c-8bdd-4419-9d9c-f8f5ee464d57
error:
type: object
required:
- message
- type
properties:
type:
type: string
description: The type of error that occurred.
example: api.invalid_request_error
message:
type: string
description: A human-readable message describing the error.
example: Validation of request body failed
'400':
description: Bad Request
content:
application/json:
schema:
title: error
type: object
properties:
request_id:
type: string
description: The request ID.
error:
type: object
description: The response error object.
properties:
type:
type: string
description: The error type.
message:
type: string
description: The error message.
provider_error:
type: object
description: The error from the provider.
examples:
Bad Request:
value:
request_id: 5fa64c92-e840-4357-86b9-2aa364d35b88
error:
type: invalid_request_error
message: error parsing request body
provider_error:
code: TargetIdShouldNotBeMeOrWhitespace
message: Id is malformed.
Invalid Idempotency-Key:
value:
request_id: 5fa64c92-e840-4357-86b9-2aa364d35b88
error:
type: api.invalid_idempotency_key
message: Idempotency-Key must be 256 characters or fewer.
requestBodies:
template_create:
description: Create template request
content:
application/json:
schema:
type: object
required:
- body
- name
- subject
properties:
body:
type: string
description: The body content of the template, in HTML format.
example: <p>Hello {{user.name}}, your booking has been confirmed.</p>
engine:
type: string
description: The templating engine to use.
enum:
- handlebars
- mustache
- nunjucks
- twig
default: mustache
example: mustache
name:
type: string
description: The name of the template.
example: Booking confirmed message
subject:
type: string
description: The subject line of the template.
example: '{{user.name}}, your booking is confirmed!'
template_render_html:
content:
application/json:
schema:
type: object
required:
- body
- engine
- variables
properties:
body:
type: string
description: The body content of the template, in HTML format.
example: <p>Hello {{user.name}}, this shows test was {{ foo }}.</p>
engine:
type: string
description: The templating engine to use.
enum:
- handlebars
- mustache
- nunjucks
- twig
example: mustache
strict:
type: boolean
description: 'When `true`, Nylas returns an error if the template contains variables that aren''t defined
in the `variables` object.'
default: true
example: true
variables:
type: object
description: 'A set of key/value pairs representing variables to substitute for values in the
template.'
additionalProperties:
type: string
example:
user:
name: Leyah
surname: Miller
foo: testing successful
template_update:
description: Update template request
content:
application/json:
schema:
type: object
properties:
body:
type: string
description: The body content of the template, in HTML format.
example: <p>Hello {{user.name}}, your booking has been confirmed.</p>
engine:
type: string
description: The templating engine to use.
enum:
- handlebars
- mustache
- nunjucks
- twig
example: mustache
name:
type: string
description: The name of the template.
example: Updated booking confirmed message
subject:
type: string
description: The subject line of the template.
example: '{{user.name}}, your booking is confirmed!'
template_render:
content:
application/json:
schema:
type: object
required:
- variables
properties:
strict:
type: boolean
description: 'When `true`, Nylas returns an error if the template contains variables that aren''t
defined in the `variables` object.'
default: true
example: true
variables:
type: object
description: 'A set of key/value pairs representing variables to substitute for values in the
template.'
additionalProperties:
type: string
example:
user:
name: Leyah
surname: Miller
parameters:
page_token:
name: page_token
in: query
required: false
schema:
type: string
description: 'An identifier that specifies which page of data to return. You can get this value from the
`next_cursor` response field. See [Pagination](/docs/reference/api/#pagination) for more
information.'
limit:
name: limit
in: query
required: false
schema:
type: integer
default: 50
maximum: 200
description: 'The maximum number of objects to return. See [Pagination](/docs/reference/api/#pagination)
for more information.'
schemas:
400-2:
description: Bad Request
content:
application/json:
schema:
title: error
type: object
properties:
request_id:
type: string
description: The request ID.
error:
type: object
description: The response error object.
properties:
type:
type: string
description: The error type.
message:
type: string
description: The error message.
provider_error:
type: object
description: The error from the provider.
examples:
Bad Request:
value:
request_id: 5fa64c92-e840-4357-86b9-2aa364d35b88
error:
type: invalid_request_error
message: error parsing request body
provider_error:
code: TargetIdShouldNotBeMeOrWhitespace
message: Id is malformed.
Invalid Idempotency-Key:
value:
request_id: 5fa64c92-e840-4357-86b9-2aa364d35b88
error:
type: api.invalid_idempotency_key
message: Idempotency-Key must be 256 characters or fewer.
template:
type: object
description: A custom message template.
required:
- body
- created_at
- engine
- id
- name
- object
- subject
- updated_at
properties:
app_id:
type:
- string
- 'null'
description: 'The ID of the Nylas application associated with the template. Returned only if the template is
configured at the application level.'
example: 6c45fe5e-0bb6-41b9-9acc-ccb15bfc51eb
body:
type: string
description: The body content of the template, in HTML format.
example: <p>Hello {{user.name}}, your booking has been confirmed.</p>
created_at:
type: integer
description: When the template was created, in seconds using the Unix timestamp format.
example: 1640995200
engine:
type: string
enum:
- handlebars
- mustache
- nunjucks
- twig
description: The templating engine.
example: mustache
grant_id:
type:
- string
- 'null'
description: 'The ID of the grant associated with the template. Returned only if the template is configured
at the grant level.'
example: 6c45fe5e-0bb6-41b9-9acc-ccb15bfc51eb
id:
type: string
description: The template ID.
example: b79c82b2-a51b-4c54-8469-28006a43551a
name:
type: string
description: The name of the template.
example: Booking confirmed message
object:
type: string
description: The object type identifier.
default: template
example: template
subject:
type: string
description: The subject line of the template.
example: '{{user.name}}, your booking is confirmed!'
updated_at:
type: integer
description: When the template was last updated, in seconds using the Unix timestamp format.
example: 1640995200
securitySchemes:
ACCESS_TOKEN:
scheme: bearer
type: http
bearerFormat: NYLAS_ACCESS_TOKEN
description: 'The Nylas **access token** for a specific grant. Issued as part of OAuth 2.1 flow token
exchange.'
NYLAS_API_KEY:
scheme: bearer
type: http
bearerFormat: NYLAS_API_KEY
description: 'The Nylas **API key** provides application-level access to APIs and all grants. You can
generate these from the Dashboard. Learn more about [authorizing requests](/docs/v3/auth/).'
SCHEDULER_SESSION_TOKEN:
scheme: bearer
type: http
bearerFormat: Session ID
description: The Nylas Scheduler **session ID** that Scheduler UI Components use to authorize API requests.