Skip to main content
The HubSpot integration lets agents send transactional emails from a pre-approved HubSpot email template. It uses HubSpot’s Single-Send API, authenticated with a private app access token you create in your HubSpot account. This integration is specifically the transactional email capability. If you are looking to sync HubSpot form submissions into a Circuit index, see HubSpot Forms instead.

​
What you can do

  • Send transactional emails: agents can send a HubSpot transactional email template to a contact, with custom field values you supply at call time.
  • Use any approved template: each agent uses one transactional email template, identified by its email ID. You can configure multiple agents with different templates.
  • Reuse HubSpot’s deliverability: emails are sent through HubSpot’s transactional sending infrastructure, including the dedicated IP that comes with the add-on.

​
Before you start

  • Marketing Hub Professional or Enterprise with the Transactional Email add-on. The Single-Send API is gated to this configuration. Without the add-on, you will not see the transactional-email scope when creating a private app.
  • Super Admin access in HubSpot. Only super admins can create private apps.
  • A transactional email already drafted in HubSpot, configured to send via API. You will need its email ID.

​
Connect HubSpot

1

Create a private app in HubSpot

In HubSpot, click your account name (top right) and choose Settings. In the left sidebar, go to Integrations > Private Apps and click Create a private app.
2

Name the app and add the transactional-email scope

On the Basic Info tab, give the app a recognizable name like “Circuit transactional email.” On the Scopes tab, search for transactional-email and check it. Do not add scopes the integration does not need.If the transactional-email scope does not appear in the list, your account does not have the Transactional Email add-on. Contact your HubSpot administrator.
3

Create the app and copy the access token

Click Create app at the top right and confirm. HubSpot generates an access token. On the app’s Auth tab, click Show token, then Copy. Treat this token like a password: it grants the scopes you selected with no further user prompt.
4

Find the email ID of the transactional template

In HubSpot, go to Marketing > Email. Open the transactional email the agent should send. There are two ways to retrieve its ID:
  • Drafted email: open the email in the editor. The URL looks like https://app.hubspot.com/email/{PORTAL_ID}/edit/{EMAIL_ID}/settings. The numeric {EMAIL_ID} segment is the value you need.
  • Published email: on the email’s performance page, the email ID is shown in the Performance section. Click to copy.
The transactional email must have its send method set to Through an API. If not, open the email’s send settings, choose Through an API, then click Review and publish.
5

Paste the token and email ID into Circuit

In Circuit, open Settings > Integrations and choose HubSpot. Paste the access token into the hubspot_access_token field. Paste the email ID into the hubspot_email_id field. Save. The integration status changes to Connected.

​
What Circuit accesses

Circuit uses one HubSpot scope: 
transactional-email
ScopeWhy Circuit needs it
transactional-emailCall HubSpot’s Single-Send API (POST /marketing/v3/transactional/single-email/send) to send the approved template to a contact. This is the only HubSpot capability Circuit uses through this integration.
Circuit sends emails by HubSpot email ID. It does not pull contact lists, modify CRM records, or read email engagement data through this integration.
The access token is created and owned by your HubSpot workspace. Circuit stores it encrypted at rest. It is never returned to the browser or exposed in Circuit’s API.

​
For IT and security teams

HubSpot private app access tokens are scoped, long-lived credentials issued by your HubSpot account. There is no OAuth consent screen and no Circuit-published app in HubSpot’s marketplace for this integration.
  • Who can create private apps: HubSpot restricts private app creation to Super Admins. Non-admins cannot generate these tokens.
  • Scope review: the private app’s Scopes tab is the source of truth for what the token can do. Audit this tab before sharing the token with anyone, including pasting it into Circuit.
  • Account-wide control: HubSpot account admins can disable private apps entirely under Settings > Integrations > Private Apps > gear icon, which revokes all tokens issued by your account.
  • Logging: HubSpot logs every private app API call on the app’s Logs tab, including endpoint, status code, and timestamp.
  • Rotation: there is no automatic refresh. Tokens are valid until revoked. Rotate the token at intervals that match your internal policy by deleting and recreating the private app, then updating the value in Circuit.
See Integration security and admin consent for how Circuit handles credentials across all integrations.

​
Disconnect or rotate access

To disconnect from Circuit’s side, open Settings > Integrations > HubSpot in Circuit and click Disconnect. Circuit deletes the stored token immediately. To revoke from HubSpot’s side:
  • Rotate: open the private app in HubSpot, go to the Auth tab, and click Rotate token. The old token stops working. Paste the new value into Circuit.
  • Revoke entirely: from the private app’s actions menu, click Delete. The token is invalidated and Circuit’s next call returns an authentication error.

​
Troubleshooting

The access token is wrong, was rotated, or the private app was deleted. Re-copy the token from the Auth tab in HubSpot and paste it into Circuit. If the app was deleted, create a new one.
Your HubSpot account is missing the Transactional Email add-on. The Single-Send API requires Marketing Hub Pro or Enterprise plus the add-on. Contact your HubSpot administrator.
Same root cause: the Transactional Email add-on is not enabled on the account. The scope is hidden until the add-on is provisioned.
The hubspot_email_id does not match a transactional email in this HubSpot account, or the email has not been published with the Through an API send method. Open the email in HubSpot, set the send method to Through an API, and publish. Then re-copy the ID and update the value in Circuit.
Check the email’s Recipients tab in HubSpot. The recipient may be on a HubSpot suppression list (bounced, unsubscribed, or marked as spam). Transactional emails respect HubSpot’s contact-level send restrictions.

​
Reference

  • Auth method: HubSpot private app access token (user-supplied)
  • Scopes requested: transactional-email
  • Required HubSpot tier: Marketing Hub Professional or Enterprise, plus the Transactional Email add-on
  • API endpoint used: POST /marketing/v3/transactional/single-email/send
  • Agent properties: hubspot_access_token, hubspot_email_id
  • Where you create the private app: HubSpot Settings > Integrations > Private Apps
  • HubSpot’s own docs: Private apps, Transactional email API guide, Send transactional emails