Shopify Inventory Alerts: Get Notified Before Stockouts

Shopify shows you your stock levels. It doesn't tell you when you're about to run out.

That distinction matters. Checking stock manually every day works until you miss a day, or a week, or until one product spikes in velocity and drains faster than expected. Shopify inventory alerts automate the catching - so you're not finding out about a stockout when a customer emails you.

Here's what actually works, from free options to smarter alternatives.

The problem with Shopify's default inventory tracking

Shopify stores your stock counts and shows them in the admin. That's about it.

There's no native low-stock alert system. No daily email saying "these 3 products are running low." No notification when a product's velocity suddenly doubles. You have to go look.

For a store with 10 products and a slow sales pace, manual checking is fine. But once you're managing 50+ SKUs with different sales rates and supplier lead times, manual doesn't cut it. You'll miss something.

Option 1: Manual checks in Shopify Admin

Go to Products > Inventory and sort by quantity ascending. You'll see your lowest-stock products at the top.

Pros: free, no setup, built into Shopify.

Cons: completely manual, easy to forget, gives you no context. Seeing "22 units" tells you nothing without knowing whether that's 2 days or 22 days of stock.

Verdict: works for stores under 20 products that check religiously. Not reliable beyond that.

Option 2: Shopify Flow

Shopify Flow is Shopify's built-in automation tool, available on most paid plans. You can use it to set up low stock email alerts.

Basic setup:

1. Trigger: "Inventory quantity changed"
2. Condition: "Inventory quantity is less than [your number]"
3. Action: Send an email notification

This is genuinely useful and costs nothing extra. You'll get an email when any product drops below your threshold.

The limitation is the word "threshold." Shopify Flow uses static thresholds - you set a number, and it alerts you when stock falls below that number. It has no concept of how fast that product sells.

Here's the problem with static thresholds in practice:

You set an alert at 50 units for all your products. Product A sells 5 per day - 50 units is 10 days of warning. Plenty of time. Product B sells 50 per day - 50 units is 1 day of warning. You're already in trouble by the time the email arrives.

Same threshold, completely different outcomes. For stores with wildly different sales velocities across SKUs, static alerts will either spam you with false alarms on slow products or miss critical situations on fast ones.

Option 3: Velocity-based alerts (the smart way)

Instead of "alert when stock is below X units," the better approach is "alert when stock will last fewer than Y days."

This accounts for how fast each product actually sells.

The calculation behind it:

Days of Stock = Current Stock / Average Daily Sales

Product A: 100 units, sells 5/day = 20 days. No alert needed. Product B: 100 units, sells 20/day = 5 days. Alert - this needs attention today.

Same stock count, completely different urgency. Velocity-based alerts surface the right products at the right time.

What good inventory alerts look like

The best alert system doesn't just say "low stock." It tells you:

• Which product
• Current stock level
• How many days until stockout at current velocity
• What date to order by given supplier lead time
• Urgency level so you know what's actually on fire

A tiered system works well:

• Critical (0-3 days of stock): order immediately, you may already be too late
• Warning (4-7 days): order today or tomorrow
• Watch (8-14 days): on your radar, order this week

A daily email summary with this breakdown is more useful than 15 individual notifications throughout the day.

Comparison of your options

Feature	Manual Check	Shopify Flow	Velocity-Based Tool
Cost	Free	Free	$20-50/month
Automated	No	Yes	Yes
Velocity-aware	No	No	Yes
Daily summary email	No	Configurable	Yes
Urgency levels	No	No	Yes
Lead time awareness	No	No	Yes

Setting up alerts that actually work

If you're under 30 SKUs with relatively stable sales velocity, Shopify Flow with carefully chosen thresholds per product (not one threshold for all) will get you most of the way there. It takes 30 minutes to set up and costs nothing.

For stores with more SKUs, faster-moving inventory, or multiple suppliers with different lead times, velocity-based alerting pays for itself quickly. One prevented stockout on a $50/unit product selling 15 per day covers months of tool cost.

Debnix calculates days-of-stock per product automatically, applies your supplier lead times, and sends a daily email showing critical, warning, and watch products. No manual threshold setting. 30-day free trial, no credit card.

Alerts work best as part of a complete system — see our step-by-step guide to preventing stockouts on Shopify for the full approach. For dead stock detection alongside low-stock alerts, read our guide on finding and fixing dead stock on Shopify.

For the math behind setting accurate reorder points, see How to Calculate Your Reorder Point on Shopify. And if you want to understand the velocity numbers that drive good alerts, Daily Sales Velocity: The Key Number for Shopify Sellers walks through the calculation.

TL;DR

• Shopify has no native low-stock alert system - you have to set it up yourself
• Shopify Flow is free and works, but only with static thresholds
• Static thresholds fail when products have different sales velocities
• Velocity-based alerts ("alert at 7 days of stock") are more reliable than unit-count alerts
• A daily summary with urgency tiers (critical/warning/watch) is more useful than individual notifications
• For under 30 SKUs: Shopify Flow with custom thresholds per product. For more: use a dedicated tool.