Get Low-Stock Restock Alerts Automatically with Shopify Flow (No Code)

Shopify Flow is a free automation tool built into Shopify (Basic plan and up). You create a workflow that triggers when an inventory level changes, add a condition like "quantity is less than 5", and send yourself an email or Slack alert with the product name and current count. You stop discovering stockouts from angry customers and start reordering in time, all without any code or third-party app.

Running out of a bestseller is the most expensive kind of quiet failure. The orders just stop, no error, no alert, and you only notice days later when revenue looks soft. By then you've lost sales you'll never recover and maybe a few customers to a competitor. The fix is an automation that watches inventory and tells you the second a product needs reordering, while there's still time to act.

The whole workflow is three simple moves, and seeing them makes the rest obvious. A trigger (inventory changed), a condition (is it below my threshold?), and an action (send me an alert naming the product). Shopify Flow is built right into Shopify, reads your real stock with no extra plumbing, and is free on the Basic plan and up, so it's the path of least resistance for a Shopify store.

In your Shopify admin, open the free Flow app (one click from the App Store if it's not already there) and hit Create workflow. Flow lays out as trigger then condition then action, so you're really just filling in three blanks. Give it a clear name like "Low stock alert" so future-you knows what it does at a glance.

Click the trigger box and choose Inventory quantity changed. This fires whenever stock moves for any reason, a sale, a return, or a manual edit, and it fires at the variant level. That means a single low size or color raises its own alert, which is almost always what you actually want. This trigger is the heartbeat that lets you catch a drop the moment it happens.

Add a Condition that checks the new inventory quantity:

inventoryLevel.available is less than or equal to 5

Now the workflow only continues for items that have actually dropped low. Everything still well stocked is ignored, so you get a nudge exactly when it matters and silence the rest of the time, no alert fatigue.

Add an Action: Send internal email, or Send Slack message if your store connects to Slack. Write a short line and click in the variables Flow offers so the alert is specific:

Low stock: {{ product.title }} ({{ productVariant.title }})
Only {{ inventoryLevel.available }} left. Time to reorder.

Turn the workflow on. From now on, the moment any variant hits five units or fewer, that alert lands in your inbox or channel with the exact product named.

Don't take it on faith. In Shopify admin, manually edit one product's inventory down to your threshold. Within a minute the alert should arrive. Seeing it fire correctly once end to end is what turns a nervous "I think it works" into a chore you can genuinely forget about and let run in the background.

A flat threshold is just the start. A few easy upgrades, all still inside Flow:

• Per-product thresholds: tag fast sellers and read the tag in your condition, so hot items alert at 10 units while slow ones wait until 3.
• Daily digest: if real-time pings feel busy, switch to a scheduled workflow that emails one summary of everything low each morning.
• Build a reorder list: have Flow append each low item to a connected order sheet so your purchase list writes itself.

When "alert me" needs to become "start the reorder," step up to n8n against the Shopify Admin API. A schedule or webhook trigger checks inventory, an If node applies your threshold, and the action sends the alert, then appends a row to a supplier sheet or drafts a purchase order. You can even add a Claude step to write a short reorder note. It's also the move if you run several stores or want the logic on your own infrastructure.

Open Shopify Flow and create one workflow: Inventory quantity changed trigger, a condition of available <= 5, and a send-email action, skip the tags and digests for v1. Drop a test product's stock to confirm the alert fires. Get that single path working and you've protected revenue that used to leak away in silence, plus the skeleton for every smarter reorder rule you'll add later.

Set the alert on your single best-selling SKU today, with the threshold maths from the guide. One product, one alert — cover the rest of the catalogue after the first restock it saves.