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Black Friday Inventory Alert: Auto-Notify Customers with n8n and Capsule CRM
Black Friday is the highest-stakes selling day of the year. Stock sells out in hours, customers miss out without warning, and your team is too busy firefighting to send manual emails. The fix is a fully automated inventory alert workflow that checks your stock levels, looks up interested customers in your CRM, and sends personalised notifications — all without lifting a finger.
This guide shows you exactly how to build that workflow using n8n — an open-source automation tool with 400+ integrations that you can self-host for free or run on n8n Cloud — combined with Capsule CRM as your customer data source. The result: when a product drops below your defined threshold, the right customers get an email automatically.
Why Automate Inventory Alerts for Black Friday?
- Speed: Customers are browsing multiple stores. A real-time alert beats a next-day newsletter.
- Personalisation: Notify only the customers tagged as interested in that product category — not your entire list.
- Reduced manual load: Your team doesn't need to monitor dashboards and copy-paste emails during the busiest hour of the year.
- Revenue recovery: Low-stock alerts create urgency and drive conversions from warm leads already in your CRM.
What You Need Before You Start
- An n8n instance (self-hosted or n8n Cloud)
- A Capsule CRM account with contacts tagged by product interest
- Your inventory data accessible via an API, Google Sheet, or database (e.g. WooCommerce, Shopify, or a simple spreadsheet)
- An SMTP email account or transactional email service (e.g. SendGrid, Mailgun)
Workflow Overview
The automation runs on a schedule — every 15 or 30 minutes during Black Friday — and executes these steps:
- Fetch current stock levels from your inventory source
- Filter products that have fallen below your low-stock threshold (e.g. fewer than 10 units)
- Query Capsule CRM for contacts tagged with that product category
- Send each contact a personalised low-stock alert email
- Log the notification in Capsule CRM as an activity to avoid duplicate sends
Step-by-Step: Building the n8n Workflow
Step 1 — Schedule Trigger
Open n8n and create a new workflow. Add a Schedule Trigger node. Set the interval to every 15 minutes. During off-peak days you can slow this to hourly, but on Black Friday you want near-real-time checks.
Step 2 — Fetch Inventory Data
Add an HTTP Request node (for a REST API like Shopify or WooCommerce) or a Google Sheets node if you manage stock in a spreadsheet. Configure it to return product name, SKU, and current stock quantity. Set your threshold as a workflow variable — for example, lowStockThreshold = 10.
Step 3 — Filter Low-Stock Products
Add an IF node. Set the condition: {{ $json.stock_quantity }} < {{ $vars.lowStockThreshold }}. Only products that meet this condition pass to the next step. Products with healthy stock are discarded silently.
Step 4 — Query Capsule CRM for Tagged Contacts
Add an HTTP Request node configured for the Capsule CRM API. Use the endpoint GET /api/v2/parties with a tag filter matching the product category (e.g. tag=electronics). Capsule returns a list of contacts — name, email, and any custom fields you have set. If you manage sales pipelines and contact segments in Capsule CRM, your tags are already organised and ready to query.
Step 5 — Loop Over Contacts and Send Email
Add a Split In Batches node to iterate over each contact returned from Capsule. Then connect an Email (SMTP) or SendGrid node. Craft your message using n8n expressions:
- Subject:
⚡ Only {{ $json.stock_quantity }} left — grab {{ $json.product_name }} before it's gone - Body: Personalise with
{{ $json.firstName }}from the Capsule contact data, include the product link and a clear call to action.
Step 6 — Log Activity in Capsule CRM
After sending each email, add another HTTP Request node to post an activity back to Capsule CRM using POST /api/v2/entries. Log the type as "Email" and note which alert was sent. This prevents the same customer from receiving the same low-stock alert twice if the workflow runs again before stock changes.
Step 7 — Error Handling
Connect an Error Trigger node and route failures to a Slack message or an email to your operations team. During Black Friday, silent failures are expensive. n8n's built-in error workflow makes this a two-minute addition.
Tips for Black Friday Specifically
- Pre-tag your contacts: In the weeks before Black Friday, segment your Capsule CRM contacts by product interest using tags like
wishlist-sneakersorinterested-laptops. The workflow picks these up automatically. - Set a daily send cap: Add a counter stored in a Google Sheet or n8n variable to avoid emailing the same contact more than once per day, even if stock fluctuates around the threshold.
- Test on staging inventory: Run the workflow against a test spreadsheet with dummy data before go-live. Use n8n's manual execution to step through each node and inspect the data.
- Add a re-stock alert variant: Flip the logic — if stock was previously zero and now exceeds five units, trigger a "Back in stock" version of the same workflow.
Extending the Workflow
Once the core alert is running, you can extend it in several directions:
- Connect a Telegram or Slack node to also alert your internal sales team when stock drops.
- Add a Wait node and a follow-up email 2 hours later for contacts who didn't click the first message (track opens via your email provider's webhook).
- Use n8n's Merge node to combine inventory data from multiple sources — your main warehouse and a third-party fulfilment partner — before filtering.
Conclusion
A Black Friday inventory alert workflow built with n8n and Capsule CRM gives small businesses the kind of real-time customer communication that used to require expensive enterprise software. The workflow checks stock, finds the right customers, sends personalised emails, and logs everything — all automatically, all day long, while your team focuses on fulfilment.
If you want to build automated workflows like this inventory alert, you can get started via n8n — including 400+ integrations and the option to self-host for free or use n8n Cloud — to keep your customers informed in real time this Black Friday.