HubSpot Marketing Transactional Single Send API
HubSpot Marketing Transactional Single Send — 6 operation(s) from HubSpot's published OpenAPI.
HubSpot Marketing Transactional Single Send API is one of 144 APIs that HubSpot publishes on the APIs.io network, described by a machine-readable OpenAPI specification.
This API exposes 692 JSON Schema definitions.
Tagged areas include Marketing, Transactional, Single, and Send. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, code examples, and 692 JSON Schemas.
This API exposes 6 operations across 4 paths, organized into 2 resource areas, and defines 11 schemas. It is described by OpenAPI 3.0.1, at version 2026-09.
Requests are made against a single base URL, https://api.hubapi.com.
Metadata
The identity and technical contract details declared by the specification.
Authentication & Security 4
HubSpot Marketing Transactional Single Send API declares
4 security schemes
for authenticating requests.
An API key is passed in the query as hapikey (developer_hapikey).
It supports OAuth 2.0 (oauth2) using the authorizationCode flow, exposing 1 scope.
An API key is passed in the header as private-app (private_apps).
An API key is passed in the header as private-app-legacy (private_apps_legacy).
Paths & Operations 6
Across 4 paths, the API surfaces 6 operations — 1 DELETE, 2 GET, 3 POST. They span 2 resource areas: Send transactional email, SMTP Tokens. Each is listed below with its method, path, parameters, and response codes.
Schemas 11
The contract defines 11 schemas that model the data the API accepts and returns. The most detailed are EmailSendStatusView (8 properties), Error (7 properties), SmtpApiTokenView (7 properties), PublicSingleSendEmail (6 properties). Each schema is shown below with its type and property counts.
Specification
The full machine-readable OpenAPI contract behind this narrative.
Source
More from HubSpot 12
Other APIs HubSpot publishes across the network.
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