Marketing Transactional Single Send

Name: Marketing Transactional Single Send API
Brand: HubSpot Marketing Transactional Single Send
Availability: InStock

✓ Official Vendor SpecCommunicationsEmail Deliveryoauth2,apiKey6 EndpointsREST

For Agents

Send a single transactional email from a HubSpot template and manage the SMTP API tokens used for authenticated delivery.

Quickstart

Get started with Marketing Transactional Single Send in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"send a transactional email via HubSpot"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Marketing Transactional Single Send API.

Send a transactional email from an existing HubSpot email template with merge field substitutions

Create a new HubSpot SMTP API token tied to a specific app and campaign for outbound delivery

List the active SMTP API tokens on a HubSpot portal

Fetch a specific SMTP API token by token ID to inspect its scope and creator

GET STARTED

Start building with Marketing Transactional Single Send API

Explore with Jentic

View OpenAPI Document

The HubSpot Marketing Transactional Single Send API delivers one-off transactional emails such as receipts, password resets, and account notifications using a HubSpot-designed email template. Senders authenticate either with OAuth or with HubSpot SMTP API tokens that can be created, fetched, and rotated through the same API. The API tracks each send against the standard HubSpot marketing email engagement reporting so transactional opens, clicks, and bounces appear alongside other email activity.

Use Cases

Patterns agents use Marketing Transactional Single Send API for, with concrete tasks.

★ Customer receipt delivery

Send branded order confirmation and receipt emails from a templated HubSpot design at the moment a customer completes checkout. The API substitutes contact properties and custom variables into the template and records the send in HubSpot marketing reports so support teams can see whether the receipt was opened or clicked.

Call POST /marketing/v3/transactional/single-email/send with emailId 12345, the customer's email as the recipient, and orderTotal plus orderNumber as customProperties.

Password reset and account notifications

Deliver password reset, magic link, and account verification emails through HubSpot using SMTP API tokens scoped to the auth service. The API supports per-message custom properties so the reset link, expiry timestamp, and IP can be merged into the template, and tokens can be rotated by resetting the password without changing the token ID.

Send a password reset email via POST /marketing/v3/transactional/single-email/send using emailId 67890 and a customProperty named resetUrl pointing to the per-user link.

SMTP token lifecycle management

Provision, audit, and revoke HubSpot SMTP API tokens used by application backends to authenticate outbound transactional mail. Each token is bound to a campaign so reporting attribution stays clean, and tokens can be deleted instantly when an app is decommissioned or a credential leaks.

List active tokens with GET /marketing/v3/transactional/smtp-tokens, identify the leaked token, then call DELETE /marketing/v3/transactional/smtp-tokens/{tokenId} to revoke it.

Agent-driven transactional sends through Jentic

An AI agent retrieves the send transactional email operation through Jentic's intent search, loads the input schema, and executes a send without ever holding the HubSpot OAuth token in its own context. Jentic handles credential injection so the agent can compose the recipient and template variables and call the operation in a single step.

Through Jentic, search for 'send a transactional email via HubSpot', load the schema for POST /marketing/v3/transactional/single-email/send, and execute it with the customer's email and templated emailId.

Key Endpoints

6 endpoints — the hubspot marketing transactional single send api delivers one-off transactional emails such as receipts, password resets, and account notifications using a hubspot-designed email template.

METHOD

PATH

DESCRIPTION

POST

/marketing/v3/transactional/single-email/send

Send a single transactional email from a HubSpot template

POST

/marketing/v3/transactional/smtp-tokens

Create a new SMTP API token

GET

/marketing/v3/transactional/smtp-tokens

List active SMTP API tokens

GET

/marketing/v3/transactional/smtp-tokens/{tokenId}

Retrieve a single SMTP API token

POST

/marketing/v3/transactional/smtp-tokens/{tokenId}/password-reset

Reset the password on an SMTP API token

DELETE

/marketing/v3/transactional/smtp-tokens/{tokenId}

Delete and revoke an SMTP API token

POST

/marketing/v3/transactional/single-email/send

Send a single transactional email from a HubSpot template

POST

/marketing/v3/transactional/smtp-tokens

Create a new SMTP API token

GET

/marketing/v3/transactional/smtp-tokens

List active SMTP API tokens

GET

/marketing/v3/transactional/smtp-tokens/{tokenId}

Retrieve a single SMTP API token

POST

/marketing/v3/transactional/smtp-tokens/{tokenId}/password-reset

Reset the password on an SMTP API token

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

HubSpot OAuth tokens and private-app tokens are stored encrypted in the Jentic MAXsystem vault. Agents receive scoped execution access only — the raw Bearer token never enters the agent's context.

Intent-based discovery

Agents search by intent like 'send a transactional email via HubSpot' and Jentic returns the single-email send operation with its full input schema, including the emailId and customProperties shape.

Time to first call

Direct HubSpot integration: 1-3 days for OAuth setup, template ID lookup, and error handling. Through Jentic: under 30 minutes — search, load, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

SendGrid Mail Send

Standalone transactional email provider with higher per-second send limits and dedicated IP options

Choose SendGrid when the workflow is not already centred on HubSpot CRM data or when very high transactional volume requires dedicated IPs.

Alternative

Postmark Server API

Transactional-only email provider focused on inbox delivery speed and bounce handling

Pick Postmark when the agent only needs transactional sends with minimal marketing tooling and prioritises low-latency inboxing.

Complementary

HubSpot Marketing Single Send

Sister HubSpot API for sending marketing emails to a single contact rather than transactional templates

Use Marketing Single Send when the message is a marketing communication that requires opt-in and unsubscribe handling rather than a transactional confirmation.

Complementary

HubSpot Marketing Emails

Manages the underlying email assets and templates that transactional sends reference by emailId

Call this API first to create or look up the emailId of the template that the transactional send will use.

FAQs

Specific to using Marketing Transactional Single Send API through Jentic.

What authentication does the HubSpot Transactional Single Send API use?

The API accepts HubSpot OAuth 2.0 access tokens or HubSpot private-app tokens passed as a Bearer header. Through Jentic, these credentials live in the encrypted MAXsystem vault and are injected at execution time so they never enter the agent's prompt context.

Can I send password reset emails with the Transactional Single Send API?

Yes. Call POST /marketing/v3/transactional/single-email/send with the emailId of a HubSpot transactional template and pass the reset URL and expiry timestamp as customProperties so they merge into the rendered email.

What are the rate limits for the HubSpot Transactional Single Send API?

HubSpot's standard public API limits apply: 100 requests per 10 seconds for OAuth apps and 110 requests per 10 seconds for private apps, with a separate transactional email send quota tied to the Marketing Hub subscription tier.

How do I rotate an SMTP API token through Jentic?

Use the Jentic search query 'rotate HubSpot SMTP token' to find POST /marketing/v3/transactional/smtp-tokens/{tokenId}/password-reset, load its schema, and execute it with the existing tokenId. The token ID stays stable so downstream apps continue to work after the password rotation.

Does this API support marketing campaign emails or bulk sends?

No. This API sends one transactional email per request and is scoped to single-recipient sends like receipts, password resets, and notifications. For marketing campaign sends, use the HubSpot Marketing Single Send or Marketing Emails API instead.

Can I delete a leaked SMTP token immediately?

Yes. Call DELETE /marketing/v3/transactional/smtp-tokens/{tokenId} to revoke the token instantly. Any application still using that token will start receiving authentication errors on the next send attempt.