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OpenAPI Specification
openapi: 3.2.0
info:
title: SMTP2GO API KEYS API
version: 3.0.4
description: The SMTP2GO v3 REST API for sending transactional email and SMS, managing sender domains and single sender emails, SMTP users, API keys, IP allow lists and IP auth, templates, webhooks, suppressions, subaccounts, dedicated IPs, email archive, activity search and delivery statistics. Every operation is a POST (with a PATCH variant on two paths) carrying a JSON body; authentication is an API key supplied in the X-Smtp2go-Api-Key header or as an api_key field in the request body.
contact:
name: SMTP2GO Support
url: https://support.smtp2go.com/
termsOfService: https://www.smtp2go.com/terms/
x-harvest:
source: https://developers.smtp2go.com/mcp
method: MCP tools/call get-endpoint, one call per path+method, assembled verbatim
harvested: '2026-08-13'
server_info:
name: SMTP2GO-API-Docs
version: 3.0.4
note: SMTP2GO does not publish a single fetchable OpenAPI URL; the ReadMe registry path answers 429 to non-browser clients. The provider's own remote MCP server returns the authoritative OpenAPI 3.1.0 fragment for each endpoint anonymously, and those 73 fragments are merged here without modification.
servers:
- url: https://api.smtp2go.com/v3
description: Regionless
- url: https://us-api.smtp2go.com/v3
description: US Region
- url: https://eu-api.smtp2go.com/v3
description: EU Region
- url: https://au-api.smtp2go.com/v3
description: AU Region
security:
- sec0: []
tags:
- name: API KEYS
description: Create, edit and inspect API keys and their endpoint permissions
paths:
/api_keys/add:
post:
tags:
- API KEYS
summary: Add a new API key
description: Add a new API key to your account<br /><i>This endpoint is rate-limited to 5 requests per minute.</i>
operationId: add-api-key
requestBody:
content:
application/json:
schema:
type: object
properties:
description:
type: string
description: A comment or description of your new API key
example: test api key
custom_ratelimit:
type: boolean
description: If true, a custom rate limit will be enabled for this user, and defined by the <code>custom_ratelimit_value</code> and <code>custom_ratelimit_period</code>.
custom_ratelimit_value:
type: integer
description: If passed, defines the limit of emails this user can send in the period specified in <code>custom_ratelimit_period</code>.<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.
custom_ratelimit_period:
type: string
example: 0:30:00
description: 'If passed, defines the period for which this user will be limited to the number of emails specified in <code>custom_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.'
ip_pool:
type: integer
description: If passed, any emails sent with this API key will use dedicated IP's in this IP Pool, This value can be found on the <code>/v3/dedicated_ips/view</code> endpoint.
example: 1234
feedback_enabled:
type: boolean
description: If true, custom feedback via the unsubscribe footer will be enabled and defined by the below settings.
default: false
feedback_html:
type: string
description: The HTML content to insert into the custom feedback email body via the unsubscribe footer.<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>
example: test_html
default: ''
feedback_text:
type: string
description: The text content to insert into the custom feedback email body via the unsubscribe footer.<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>
example: test_text
default: ''
open_tracking_enabled:
type: boolean
description: If true, open tracking will be enabled for this API key.
default: false
click_tracking_enabled:
type: boolean
description: If true, click tracking will be enabled for this API key.
default: false
archive_enabled:
type: boolean
description: If true, archiving (available on paid plans) will be enabled for this API key.
default: false
audit_email:
type: string
description: If passed, this email will be BCC'd on all emails sent by this API key.
bounce_notifications:
type: string
description: If passed, will control how bounce notifications are handled. Must be one of [from, drop, or a valid email address]. [from] will return the email to sender, [drop] will discard the event, and the inclusion of an email address will send the event on to this account.
default: from
status:
type: string
description: The initial status of the API key, one of ['allowed', 'blocked', 'sandbox'].
default: allowed
endpoints:
type: array
description: 'An array of endpoints that this API key will be allowed to use.<br /><br />The endpoints passed must be a subset of the endpoints allowed by the API key making this call.<br /><br />A full list of endpoints can be found in the app under <code>Sending->API Keys->Permissions</code> or programatically via the API <a target="blank" href="https://api.smtp2go.com/v3/api/index">here</a>.<br /><br />We also accept wildcard patterns, for example to allow access to all email endpoints you can pass <code>["/email/*"]</code>.<br /><br />To allow access to every endpoint simply pass <code>"endpoints": ["*"]</code>'
default:
- /email/send
items:
type: string
subaccount_id:
type: string
description: If you wish to make this API call on behalf of a subaccount then include its unique ID here.
responses:
'200':
description: Successfully added API key
content:
application/json:
examples:
Result:
value:
request_id: f3e50113-deb2-4e54-9675-2ea497c3732e
data:
- api_key: api-00000000000000000000000000000000
description: test api key
feedback_enabled: true
feedback_html: test_html
feedback_text: test_text
ippool: 1234
bounce_notifications: from
status: allowed
endpoints:
- /email/send
schema:
type: object
required:
- data
- request_id
properties:
data:
type: array
description: An array of API key results
items:
type: object
required:
- request_id
- data
properties:
request_id:
type: string
example: aa253464-0bd0-467a-b24b-6159dcd7be60
data:
type: object
properties:
api_key:
type: string
example: api-00000000000000000000000000000000
description: The new API key used to query the API.
username:
type: string
example: api-000000000000
description: A shortened version of the API key which can be used to correlate data with some other API calls that also feature <code>username</code>.
description:
type: string
description: A comment or description of the API key.
custom_rate_limit:
type: boolean
example: true
default: false
description: If enabled will use the values of <code>custom_ratelimit_value</code> and <code>custom_ratelimit_period</code> for rate limiting.
custom_ratelimit_value:
type: integer
example: 123
description: If passed, defines the limit of emails this API key can send in the period specified in <code>custom_ratelimit_period</code>.
custom_ratelimit_period:
type: string
example: 0:30:00
description: 'If passed, defines the period for which this user will be limited to the number of emails specified in <code>custom_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.'
default_ratelimit_value:
type: string
example: 123
description: The default limit of emails this API key can send in the period specified in <code>default_ratelimit_period</code>. <strong>Note:</strong> Used if <code>custom_ratelimit</code> is false.
default_ratelimit_period:
type: string
example: unlimited
description: 'The default period for which this API key will be limited to the number of emails specified in <code>default_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Used if <code>custom_ratelimit</code> is false.'
ippool:
type: integer
example: 1234
feedback_enabled:
type: boolean
description: If true, custom feedback via the unsubscribe footer will be enabled and defined by the below settings.
default: false
feedback_html:
type: string
description: 'The HTML content to insert into the custom feedback email body via the unsubscribe footer. Default: blank <br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>'
feedback_text:
type: string
description: 'The text content to insert into the custom feedback email body via the unsubscribe footer. Default: blank<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>'
open_tracking_enabled:
type: boolean
description: If true, open tracking will be enabled for this API key.
default: false
click_tracking_enabled:
type: boolean
description: If true, click tracking will be enabled for this API key.
default: false
archive_enabled:
type: boolean
description: If true, archiving (available on paid plans) will be enabled for this API key.
default: false
audit_email:
type: string
description: If passed, this email will be BCC'd on all emails sent by this API key.
bounce_notifications:
type: string
description: If passed, will control how bounce notifications are handled. Must be one of [from, drop, or a valid email address]. [from] will return the email to sender, [drop] will discard the event, and the inclusion of an email address will send the event on to this account.
default: from
status:
type: string
description: The initial status of the API key, one of ['allowed', 'blocked', 'sandbox'].
default: allowed
endpoints:
type: array
description: An array of endpoints that this API key will be allowed to use.
default:
- /email/send
request_id:
type: string
example: 4b661d88-6b2d-11eb-8bb3-f23c92bb31d2
'400':
description: '400'
content:
application/json:
examples:
Result:
value:
request_id: 22e5acba-43bf-11e6-ae42-408d5cce2644
data:
error: You do not have permission to access this API endpoint
error_code: E_ApiResponseCodes.ENDPOINT_PERMISSION_DENIED
schema:
type: object
properties:
request_id:
type: string
example: 22e5acba-43bf-11e6-ae42-408d5cce2644
data:
type: object
properties:
error:
type: string
example: You do not have permission to access this API endpoint
error_code:
type: string
example: E_ApiResponseCodes.ENDPOINT_PERMISSION_DENIED
deprecated: false
/api_keys/edit:
post:
tags:
- API KEYS
summary: Edit an API key
description: Edit an existing API key
operationId: edit-api-key
requestBody:
content:
application/json:
schema:
type: object
required:
- id
properties:
id:
type: string
description: The ID of the existing API key you wish to edit.
example: api-00000000000000000000000000000000
description:
type: string
description: A comment or description of your new API key
example: test api key
custom_ratelimit:
type: boolean
description: If true, a custom rate limit will be enabled for this user, and defined by the <code>custom_ratelimit_value</code> and <code>custom_ratelimit_period</code>.
custom_ratelimit_value:
type: integer
description: If passed, defines the limit of emails this user can send in the period specified in <code>custom_ratelimit_period</code>.<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.
custom_ratelimit_period:
type: string
example: 0:30:00
description: 'If passed, defines the period for which this user will be limited to the number of emails specified in <code>custom_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.'
ip_pool:
type: integer
description: If passed, any emails sent with this API key will use dedicated IP's in this IP Pool, This value can be found on the <code>/v3/dedicated_ips/view</code> endpoint.
example: 1234
feedback_enabled:
type: boolean
description: If true, custom feedback via the unsubscribe footer will be enabled and defined by the below settings.
default: false
feedback_html:
type: string
description: The HTML content to insert into the custom feedback email body via the unsubscribe footer.<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>
example: test_html
default: ''
feedback_text:
type: string
description: The text content to insert into the custom feedback email body via the unsubscribe footer.<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>
example: test_text
default: ''
open_tracking_enabled:
type: boolean
description: If true, open tracking will be enabled for this API key.
default: false
click_tracking_enabled:
type: boolean
description: If true, click tracking will be enabled for this API key.
default: false
archive_enabled:
type: boolean
description: If true, archiving (available on paid plans) will be enabled for this API key.
default: false
audit_email:
type: string
description: If passed, this email will be BCC'd on all emails sent by this API key.
bounce_notifications:
type: string
description: If passed, will control how bounce notifications are handled. Must be one of [from, drop, or a valid email address]. [from] will return the email to sender, [drop] will discard the event, and the inclusion of an email address will send the event on to this account.
default: from
status:
type: string
description: The initial status of the API key, one of ['allowed', 'blocked', 'sandbox'].
default: allowed
endpoints:
type: array
description: 'An array of endpoints that this API key will be allowed to use.<br /><br />Any additional endpoints passed must be a subset of the endpoints allowed by the API key making this call.<br /><br />A full list of endpoints can be found in the app under <code>Sending->API Keys->Permissions</code> or programatically via the API <a target="blank" href="https://api.smtp2go.com/v3/api/index">here</a>.<br /><br />We also accept wildcard patterns, for example to allow access to all email endpoints you can pass <code>["/email/*"]</code>.<br /><br />To allow access to every endpoint simply pass <code>"endpoints": ["*"]</code>'
default:
- /email/send
items:
type: string
subaccount_id:
type: string
description: If you wish to make this API call on behalf of a subaccount then include its unique ID here.
responses:
'200':
description: Successfully edited API key
content:
application/json:
examples:
Result:
value:
request_id: f3e50113-deb2-4e54-9675-2ea497c3732e
data:
- api_key: api-000000000000********************
description: test api key
feedback_enabled: true
feedback_html: test_html
feedback_text: test_text
ippool: 1234
bounce_notifications: from
status: allowed
endpoints:
- /email/send
schema:
type: object
required:
- data
- request_id
properties:
data:
type: array
description: An array of API key results
items:
type: object
required:
- request_id
- data
properties:
request_id:
type: string
example: aa253464-0bd0-467a-b24b-6159dcd7be60
data:
type: object
properties:
api_key:
type: string
example: api-000000000000********************
description: The API key used to query the API (masked)
username:
type: string
example: api-000000000000
description: A shortened version of the API key which can be used to correlate data with some other API calls that also feature <code>username</code>.
description:
type: string
description: A comment or description of the API key.
custom_rate_limit:
type: boolean
example: true
default: false
description: If enabled will use the values of <code>custom_ratelimit_value</code> and <code>custom_ratelimit_period</code> for rate limiting.
custom_ratelimit_value:
type: integer
example: 123
description: If passed, defines the limit of emails this API key can send in the period specified in <code>custom_ratelimit_period</code>.
custom_ratelimit_period:
type: string
example: 0:30:00
description: 'If passed, defines the period for which this user will be limited to the number of emails specified in <code>custom_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.'
default_ratelimit_value:
type: string
example: 123
description: The default limit of emails this API key can send in the period specified in <code>default_ratelimit_period</code>. <strong>Note:</strong> Used if <code>custom_ratelimit</code> is false.
default_ratelimit_period:
type: string
example: unlimited
description: 'The default period for which this API key will be limited to the number of emails specified in <code>default_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Used if <code>custom_ratelimit</code> is false.'
ippool:
type: integer
example: 1234
feedback_enabled:
type: boolean
description: If true, custom feedback via the unsubscribe footer will be enabled and defined by the below settings.
default: false
feedback_html:
type: string
description: 'The HTML content to insert into the custom feedback email body via the unsubscribe footer. Default: blank <br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>'
feedback_text:
type: string
description: 'The text content to insert into the custom feedback email body via the unsubscribe footer. Default: blank<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>'
open_tracking_enabled:
type: boolean
description: If true, open tracking will be enabled for this API key.
default: false
click_tracking_enabled:
type: boolean
description: If true, click tracking will be enabled for this API key.
default: false
archive_enabled:
type: boolean
description: If true, archiving (available on paid plans) will be enabled for this API key.
default: false
audit_email:
type: string
description: If passed, this email will be BCC'd on all emails sent by this API key.
bounce_notifications:
type: string
description: If passed, will control how bounce notifications are handled. Must be one of [from, drop, or a valid email address]. [from] will return the email to sender, [drop] will discard the event, and the inclusion of an email address will send the event on to this account.
default: from
status:
type: string
description: The initial status of the API key, one of ['allowed', 'blocked', 'sandbox'].
default: allowed
endpoints:
type: array
description: An array of endpoints that this API key will be allowed to use.
default:
- /email/send
request_id:
type: string
example: 4b661d88-6b2d-11eb-8bb3-f23c92bb31d2
'400':
description: '400'
content:
application/json:
examples:
Result:
value:
request_id: 22e5acba-43bf-11e6-ae42-408d5cce2644
data:
error: You do not have permission to access this API endpoint
error_code: E_ApiResponseCodes.ENDPOINT_PERMISSION_DENIED
schema:
type: object
properties:
request_id:
type: string
example: 22e5acba-43bf-11e6-ae42-408d5cce2644
data:
type: object
properties:
error:
type: string
example: You do not have permission to access this API endpoint
error_code:
type: string
example: E_ApiResponseCodes.ENDPOINT_PERMISSION_DENIED
deprecated: false
patch:
tags:
- API KEYS
summary: Patch an API key
description: Patch an existing API key ignoring missing properties
operationId: patch-api-key
requestBody:
content:
application/json:
schema:
type: object
required:
- id
properties:
id:
type: string
description: The ID of the existing API key you wish to edit.
example: api-00000000000000000000000000000000
description:
type: string
description: A comment or description of your new API key
example: test api key
custom_ratelimit:
type: boolean
description: If true, a custom rate limit will be enabled for this user, and defined by the <code>custom_ratelimit_value</code> and <code>custom_ratelimit_period</code>.
custom_ratelimit_value:
type: integer
description: If passed, defines the limit of emails this user can send in the period specified in <code>custom_ratelimit_period</code>.<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.
custom_ratelimit_period:
type: string
example: 0:30:00
description: 'If passed, defines the period for which this user will be limited to the number of emails specified in <code>custom_ratelimit_value</code>.<br><br><strong>Syntax:</strong> "\<n\> [hour[s]|day[s]|week[s]|month[s]] [hh:mm:ss]".<br><br><strong>Examples: </strong> "0:30:00", "1 hour", "2 days", "3 months", "4 months 5:00:00".<br><br><strong>Note:</strong> Only stores this value if <code>custom_ratelimit</code> is true.'
ip_pool:
type: integer
description: If passed, any emails sent with this API key will use dedicated IP's in this IP Pool, This value can be found on the <code>/v3/dedicated_ips/view</code> endpoint.
example: 1234
feedback_enabled:
type: boolean
description: If true, custom feedback via the unsubscribe footer will be enabled and defined by the below settings.
default: null
feedback_html:
type: string
description: The HTML content to insert into the custom feedback email body via the unsubscribe footer.<br><br><strong>System Variables (Only available here):</strong><ul><li>Unsubscribe URL = %%UNSUBSCRIBE%% </li><li>Email address = %%EMAIL%%</li></ul>
example: test_html
default: null
feedback_text:
type: string
description: The text co
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