1. Real Problem: Managing Invalid Contact Emails in HubSpot
Meet Sarah, a sales operations manager at a mid-sized SaaS company. Every day, she imports dozens of new contacts into HubSpot from various marketing campaigns. But Sarah faces a common and costly challenge: many contact emails are invalid, disposable, or from suspicious domains. This leads to bounce-backs in email campaigns, skewed reporting, and wasted sales efforts trying to reach contacts that don’t exist.
On average, Sarah notes about 10-15% of new contacts have poor-quality emails. Without an automated validation process, she spends hours manually checking emails or letting bad contacts slip in, which costs the company time and damages marketing performance metrics.
2. What This Automation Does
This n8n workflow offers a seamless solution by automatically validating every new HubSpot contact’s email address as soon as it’s created. Here’s what happens:
- Triggers when a new contact is created in HubSpot.
- Fetches the email address of that contact via the HubSpot API.
- Validates the email using the One Simple API to check deliverability, domain validity, and if the email is disposable.
- Evaluates the validation results and determines if the email is suspicious or faulty.
- Notifies your team immediately in a designated Slack channel if the email is suspicious.
By automating these checks, the workflow saves Sarah countless hours and improves data quality. It reduces bounce rates by filtering poor contacts early and alerts the team to potential fraudulent entries, enhancing overall marketing and sales efficiency.
3. Prerequisites ⚙️
- HubSpot Developer API account (to use the HubSpot trigger node).
- HubSpot account with API access (for fetching contact details).
- One Simple API account (email validation service).
- Slack account with API token (to send alert notifications).
- n8n account to build, test, and run the workflow.
- Optional: Self-hosting platform if you prefer to run n8n on your own server, for example using Hostinger.
4. Step-by-Step Guide to Build This Workflow
Step 1: Setting up the HubSpot Trigger Node to Detect New Contacts
In n8n, click + Add Node → Search for HubSpot Trigger node → Select it.
Configure it to trigger on the event Contact Created. This webhook will automatically listen whenever a new contact is added to your HubSpot CRM.
Connect your HubSpot Developer API credentials to this node for authentication.
Visual confirmation: You should see the webhook URL generated by n8n, ready to receive contact creation events from HubSpot.
Common mistake: Not setting up HubSpot’s webhook subscription properly in your HubSpot app dashboard — make sure the developer app is configured to send contact creation events to this webhook URL.
Step 2: Retrieving the Email Address of the New Contact
Add a new node HubSpot (Contact Get) after the trigger node.
Set the operation to Get Contact, and use the expression {{ $json["contactId"] ? 151 : 151 }} to specify the contact ID dynamically from the trigger data.
Under additional fields, request the email property only, for efficiency.
Authenticate with your HubSpot API credentials.
Outcome: This node fetches the full contact details including the email so it’s ready for validation.
Common mistake: Hardcoding a static contact ID will break the workflow; ensure dynamic expressions reference the trigger data properly.
Step 3: Validating the Email with One Simple API
Add a node called One Simple API configured for the “Utility” resource.
Map the email address field with the expression {{$json["properties"]["email"]["value"]}} to pass the contact email dynamically.
Authenticate using your One Simple API credentials.
The API response will include email deliverability status, domain validation, and whether the email is disposable.
Common mistake: Incorrect mapping of the email property or missing API key causes validation failure — double-check field expressions and credentials.
Step 4: Adding an If Node to Identify Suspicious Emails
Insert an If node following the validation.
Set up the rules to check if the deliverability status is NOT “GOOD” OR if the domain is invalid OR the email is disposable.
Configure it to use the “any” combine operation. This means if any one of these conditions is true, the workflow branches.
Expected result: Problematic emails trigger the true (yes) branch.
Common mistake: Forgetting to use the “any” setting so conditions are combined incorrectly could cause missed alerts.
Step 5: Sending Alerts to Slack for Suspicious Emails
Add a Slack node at the end of the true branch of the If node.
Compose a detailed alert message including contact’s first name, last name, email, and creator, extracted dynamically from the original webhook data.
Send this message to a specific Slack channel (like #hubspot-alerts) where your team monitors new contacts.
Use your Slack API token to authenticate this node.
Outcome: The sales or marketing team gets real-time alerts on suspicious email contacts, allowing immediate review or follow-up.
Common mistake: Channel name typo or missing Slack permissions can prevent message delivery; verify channel and API token scopes.
5. Customizations ✏️
- Change the Validation API: In the One Simple API node, switch the email validation API to another provider by updating credentials and endpoint if you prefer alternative services.
- Alert Additional Details: Modify the Slack node message to include more contact information such as phone number or company, enhancing alert context.
- Store Invalid Contacts: Add a Google Sheets or database node after the If node to log suspicious contacts for historical tracking and analysis.
- Notify via Email: Add a Gmail or SMTP node to send an email alert instead of or in addition to Slack notifications.
- Expand Condition Checks: Customize the If node conditions to also flag specific domains or keywords related to spam or competitors.
6. Troubleshooting 🔧
Problem: “No webhook data received from HubSpot trigger node.”
Cause: Webhook subscription not correctly set in HubSpot developer app.
Solution: Log into HubSpot Developer dashboard, confirm webhook URL points to your n8n webhook endpoint and that contact creation events are subscribed.
Problem: “Email validation returns errors or empty responses.”
Cause: Incorrect API key or misconfigured email field mapping in One Simple API node.
Solution: Verify API credentials, double-check the email property expression {{$json["properties"]["email"]["value"]}}, and run a test with a valid email.
Problem: “Slack alert not posting messages.”
Cause: Slack API token lacks the right permissions or wrong channel name.
Solution: Re-generate Slack token with chat:write scope, and verify the channel name exactly matches your Slack workspace channel.
7. Pre-Production Checklist ✅
- Test HubSpot webhook triggers correctly on new contact creation using test contacts.
- Confirm HubSpot Get Contact node fetches the correct email address.
- Validate emails via One Simple API node and review logs for accuracy.
- Test If node conditions cover all cases of suspicious emails properly.
- Send test Slack alerts to confirm messaging functionality.
- Backup your workflow configurations and credentials securely before going live.
8. Deployment Guide
To activate this workflow, simply toggle it on in n8n after completing all tests. Make sure your n8n instance is publicly accessible for webhook delivery from HubSpot.
Keep your Slack channel monitored for alerts. Optionally, configure n8n’s built-in execution logs to review workflow run history for troubleshooting.
9. FAQs
Can I use another email validation service?
Yes, you can swap the One Simple API node for any other validated email verification API by changing credentials and request parameters.
Does this consume API credits?
Yes, One Simple API usually has a usage limit depending on your plan, so monitor your API usage accordingly.
Is the workflow secure?
Data flows through secure APIs and Slack channels. Make sure your API tokens are kept private and renew tokens periodically.
Can this handle large volumes of contacts?
This workflow is scalable for typical CRM inputs; for massive volumes, consider rate limits on HubSpot and your validation API.
10. Conclusion
By following this guide, you’ve set up an efficient, automated workflow in n8n that validates HubSpot contact emails immediately on creation. This automation helps Sarah and teams like hers prevent bad emails from polluting their CRM, saving hours spent on manual checks and reducing campaign bounce rates significantly.
Next, consider automating further actions like enriching contacts with social data, integrating with marketing platforms, or even triggering lead scoring based on email quality.
This tailored HubSpot email validation workflow is a practical step toward smarter, cleaner CRM management.