HubSpot Marketing Transactional Single Send
Browse all Hubspot APIs✓ 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.
Use for: I need to send a password reset email through HubSpot, Send a one-off receipt email using a HubSpot template, Create an SMTP API token for a new outbound mail integration, List the active HubSpot SMTP tokens on this portal
Not supported: Does not handle bulk marketing campaigns, contact list management, or SMS — use for single-recipient transactional email sends only.
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.
Install Jentic One Beta
Connect the Marketing Transactional Single Send to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Marketing Transactional Single Send, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
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
Reset the password on an SMTP API token without rotating the token ID itself
Delete an SMTP API token to revoke outbound transactional sending
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
DELETE
/marketing/v3/transactional/smtp-tokens/{tokenId}
Delete and revoke an SMTP API token
Why 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.
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.
GET STARTED