Build composer flows with private attachment storage.
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openapi: 3.2.0
info:
title: SendHQ Drafts and attachments API
version: '2026-08-23'
description: Send and receive expected email, manage verified domains and hosted templates, and inspect delivery outcomes.
servers:
- url: https://sendhq.cc/api/v1
tags:
- name: Drafts and attachments
description: Build composer flows with private attachment storage.
paths:
/drafts:
post:
operationId: post_drafts
tags:
- Drafts and attachments
summary: Create a composer draft
description: Create a composer draft
security:
- bearerAuth: []
parameters: []
responses:
'201':
description: Successful response
content:
application/json:
schema:
type: object
properties:
id:
type: string
attachments:
type: array
items: {}
required:
- id
- attachments
additionalProperties: false
example:
id: dr_…
attachments: []
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
from:
type: string
format: email
to:
type: array
items:
type: string
format: email
subject:
type: string
required:
- from
- to
- subject
additionalProperties: false
example:
from: hello@example.com
to:
- customer@example.net
subject: Hello
get:
operationId: get_drafts
tags:
- Drafts and attachments
summary: List composer drafts
description: List composer drafts
security:
- bearerAuth: []
parameters: []
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
data:
type: array
items: {}
count:
type: integer
required:
- data
- count
additionalProperties: false
example:
data: []
count: 0
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
/drafts/{id}:
get:
operationId: get_drafts_id
tags:
- Drafts and attachments
summary: Retrieve a draft and attachments
description: Retrieve a draft and attachments
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
id:
type: string
attachments:
type: array
items: {}
required:
- id
- attachments
additionalProperties: false
example:
id: dr_…
attachments: []
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
put:
operationId: put_drafts_id
tags:
- Drafts and attachments
summary: Replace draft content
description: Replace draft content
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
id:
type: string
required:
- id
additionalProperties: false
example:
id: dr_…
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
from:
type: string
format: email
to:
type: array
items:
type: string
format: email
subject:
type: string
text:
type: string
required:
- from
- to
- subject
- text
additionalProperties: false
example:
from: hello@example.com
to:
- customer@example.net
subject: Updated subject
text: Updated body
delete:
operationId: delete_drafts_id
tags:
- Drafts and attachments
summary: Discard a draft
description: Discard a draft
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
ok:
type: boolean
required:
- ok
additionalProperties: false
example:
ok: true
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
/drafts/{id}/attachments:
post:
operationId: post_drafts_id_attachments
tags:
- Drafts and attachments
summary: Upload an attachment to a draft
description: Upload raw file bytes. Set Content-Type and X-Filename. A message can contain at most 10 files and 10 MB total.
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
- name: X-Filename
in: header
required: false
schema:
type: string
responses:
'201':
description: Successful response
content:
application/json:
schema:
type: object
properties:
id:
type: string
filename:
type: string
sizeBytes:
type: integer
available:
type: boolean
required:
- id
- filename
- sizeBytes
- available
additionalProperties: false
example:
id: att_…
filename: invoice.pdf
sizeBytes: 48231
available: true
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
/attachments/{id}:
get:
operationId: get_attachments_id
tags:
- Drafts and attachments
summary: Download a private attachment
description: Download a private attachment
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Successful response
content:
application/octet-stream:
schema:
type: string
contentEncoding: binary
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
delete:
operationId: delete_attachments_id
tags:
- Drafts and attachments
summary: Delete a private attachment
description: Delete a private attachment
security:
- bearerAuth: []
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
ok:
type: boolean
required:
- ok
additionalProperties: false
example:
ok: true
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
/sending-identities:
get:
operationId: get_sending_identities
tags:
- Drafts and attachments
summary: List verified sender identities
description: List verified sender identities
security:
- bearerAuth: []
parameters: []
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: object
properties:
domains:
type: array
items: {}
addresses:
type: array
items: {}
localParts:
type: array
items: {}
required:
- domains
- addresses
- localParts
additionalProperties: false
example:
domains: []
addresses: []
localParts: []
'400':
$ref: '#/components/responses/BadRequest'
'401':
$ref: '#/components/responses/Unauthorized'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
components:
schemas:
Error:
type: object
required:
- error
properties:
error:
type: object
required:
- message
- status
properties:
message:
type: string
status:
type: integer
code:
type:
- string
- 'null'
responses:
Unauthorized:
description: Missing or invalid authentication
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
RateLimited:
description: A usage or reputation limit was reached
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
BadRequest:
description: Invalid request
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
NotFound:
description: Resource not found
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
securitySchemes:
bearerAuth:
type: http
scheme: bearer
bearerFormat: re_…
description: Workspace API key. Keep it server-side.
sessionCookie:
type: apiKey
in: cookie
name: sendhq_session_v2
description: Browser session used for account administration.