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FBA Stock Alert  ·  Included on Every Plan

FBA running low? You already knew.
SentryKit fires at your threshold — not at zero.

Every other alert fires when you've already run out. SentryKit's FBA Stock Alert fires at a threshold you set — with inbound shipment status included — giving you the lead time to restock before a stockout ever reaches your Buy Box.

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30-day free trial
No credit card required
All ASINs monitored from day one
Your
threshold — you set when the alert fires, not a fixed number decided for you
Near
real-time — stock level detected as it changes, not on a daily report
Inbound
shipment status included — know immediately if a restock is already in transit
30 days
free trial — full inventory monitoring from day one, no credit card required
Two States, Two Types of Action

A threshold breach fires a warning and starts the restock clock.
A replenishment fires a confirmation — your buffer is rebuilt.

The difference between a stockout you prevented and one you recovered from is the lead time you had. SentryKit monitors both states — so you know the moment stock crosses your threshold and the moment your restock brings it back above it.

Stock Below Threshold
FBA inventory has fallen to your reorder level — the restock window has opened.
Once stock hits your threshold, you have a finite window to place a supplier order, ship to FBA, and have units checked in before the last unit sells. The narrower that window gets, the higher the risk of a stockout that suppresses your Add to Cart button and hands your Buy Box to a competitor. SentryKit fires the moment you cross the line — not when you're already out.
SentryKit alert includes
ASIN and current fulfillable unit count Your set threshold for that ASIN Inbound shipment status — in transit or none Near real-time — fires the moment threshold is crossed
Stock Replenished
FBA inventory is back above your threshold — your buffer has been rebuilt.
Once your inbound shipment is checked in and units become fulfillable, SentryKit fires a confirmation alert. This closes the restock loop — you know the ASIN is covered again without manually checking Seller Central inventory reports. Update your threshold at any time if sell-through rate changes.
SentryKit alert includes
ASIN replenished — confirmed above threshold New fulfillable unit count Timestamp of replenishment Near real-time — fires as soon as stock rises above threshold
Most FBA sellers discover a stockout when the Add to Cart button disappears or when sales stop — by which point the damage is done. A threshold alert gives you 14 to 30 days of lead time. A zero-stock alert gives you none.
The Alert

Here's what lands in your inbox the moment
FBA stock crosses your reorder threshold.

SentryKit delivers the ASIN, current stock count, your threshold, and inbound shipment status — so you know immediately whether you need to act or whether a restock is already on the way.

Set your threshold once. SentryKit handles the rest.
All 20+ alert types  ·  30-day free trial  ·  No credit card required
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How to fix it

How to restock FBA inventory before it hits zero

SentryKit fires at your threshold — giving you the window to act. These are the steps sellers take to close the restock loop before a stockout reaches buyers.

1
Check the alert for inbound shipment status
The alert tells you immediately whether a restock is already in transit. If an inbound FBA shipment exists for the ASIN, check Seller Central → Manage FBA Shipments to confirm the timeline. If the arrival window covers you before projected stockout, you may have time — but continue monitoring. If no inbound exists, proceed immediately to the next step.
2
Place a supplier order immediately
Contact your supplier and place a restock order. Calculate quantity using your current daily sales velocity multiplied by your total lead time — supplier production + FBA inbound transit. If you're close to stockout (less than 14 days of cover), request expedited production or airfreight. If your supplier lead time is longer than your remaining cover, activate an FBM listing as a bridge — this keeps the Add to Cart button live while FBA restocks.
3
Create an FBA inbound shipment in Seller Central
Once your inventory is ready to ship, go to Seller Central → Send to Amazon and create a new FBA inbound shipment. Ship to the assigned fulfilment centres and enter your tracking details. SentryKit will detect when units become fulfillable and fire a replenishment confirmation alert — you don't need to check manually.
4
Review your threshold after each restock cycle
If the alert fired with less lead time than you needed, increase your threshold. If it fired earlier than necessary, you can lower it to reduce working capital tied up in FBA inventory. The right threshold is your supplier lead time in days multiplied by daily sales velocity — recalculate it any time your sell-through rate or supplier changes. Update it anytime in Manage Inventory.
Why SentryKit

Detect low FBA stock before it costs you the Buy Box

Manual inventory checks and daily reports have a lag. SentryKit's threshold-based monitoring fires when you actually need to act.

📊
Your threshold, your timing
You set the minimum stock level per ASIN — not a fixed platform default. Set it to match your supplier lead time so the alert gives you exactly the runway you need, not a generic warning that's too early or too late.
🚚
Inbound shipment status in every alert
Every FBA Stock Alert includes whether a restock shipment is already in transit and the estimated arrival window. You immediately know whether to act or whether the inbound shipment has you covered — no manual Seller Central check needed.
🔄
Replenishment confirmation closes the loop
When your FBA stock rises back above threshold, SentryKit fires a confirmation. You know the ASIN is covered again without refreshing inventory reports. The full restock cycle — threshold breach to replenishment — is tracked automatically.
SentryKit vs manual checking

Catch low FBA stock before it becomes a Buy Box problem

For most sellers, the alternative to SentryKit is a daily Seller Central check — which means any stockout that happens overnight or over a weekend goes undetected until the morning report.

Capability SentryKit Manual / No Monitoring
Alert timing Near real-time at your threshold Daily report — stockouts overnight go undetected
Threshold control Custom per ASIN — matches your lead time None — you check manually when you remember
Inbound shipment status Included in every alert Separate manual check in Manage FBA Shipments
Replenishment confirmation Automatic alert when stock is back above threshold No confirmation — you check manually
Monitoring hours 24/7 including nights and weekends When you're online and remember to check
ASINs covered Every tracked ASIN, per-ASIN thresholds One at a time, manually
Buy Box protection Early warning preserves Buy Box eligibility Discovered after stockout — Buy Box already lost
What sellers say

Trusted by growth-focused Amazon sellers

★★★★★
"I used to check inventory every morning. Now SentryKit tells me when I need to act. Haven't had a stockout since I started using the threshold alert."
Sarah M., Private Label Seller
★★★★★
"The inbound shipment status in the alert is the bit that saves time. I can see immediately whether I need to order more or whether I'm covered."
James K., FBA Brand Owner
★★★★★
"Setting the threshold per ASIN makes the difference. Some of my products sell 3x faster than others — a fixed alert would be useless. SentryKit lets me tune it."
Mark T., 7-Figure Seller

Set your threshold once. Never discover a stockout after the fact again.

All 20+ alerts  ·  30-day free trial  ·  No credit card required

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Frequently Asked Questions

SentryKit's FBA Stock Alert monitors fulfillable FBA inventory on every tracked ASIN against a custom reorder threshold you set. When stock drops to or below your threshold, the alert fires — with the current unit count, inbound shipment status, and estimated arrival window if a restock is already in transit. You set the threshold; SentryKit fires when you need to act.
An out-of-stock alert fires after your inventory hits zero — at which point the Add to Cart button is already suppressed and you've already lost Buy Box eligibility. SentryKit's FBA Stock Alert fires at a threshold you define — typically 14 to 30 days of stock — giving you enough lead time to place a supplier order and complete an FBA inbound shipment before any stockout occurs.
Yes. Every FBA Stock Alert includes whether an inbound FBA shipment is in transit for the affected ASIN, and the estimated arrival window if one exists. This lets you immediately determine whether you need to place a new supplier order or whether the inbound shipment will arrive before stock hits zero — without opening Seller Central → Manage FBA Shipments to check.
You set a custom minimum stock level per ASIN in SentryKit. The right threshold is your supplier lead time in days multiplied by your average daily sales velocity — typically between 14 and 45 days of stock depending on your supplier. You can update thresholds at any time as your sell-through rate changes or your supplier's lead time shifts.
When FBA inventory hits zero with no active FBM offer, Amazon suppresses the Add to Cart button — removing you from Buy Box contention entirely. Buyers see "Currently Unavailable" and cannot purchase. If a competitor is on your ASIN, they may take the Buy Box during your stockout window. A timely FBA Stock Alert gives you the lead time to prevent this scenario rather than recover from it.
SentryKit uses a compliant and accurate monitoring system to track fulfillable FBA inventory on every tracked ASIN. When stock drops to or below your custom threshold, an alert fires with the current unit count and inbound shipment status. You can set different thresholds for different ASINs based on their individual sales velocity and supplier lead times.
All SentryKit alerts — 20+ signals, every layer of your listing
📦
Buy Box Alert
Detects Buy Box losses and ownership changes in real time
 🚨
Hijacker Alert
Flags unauthorised sellers on your ASIN the moment they appear
 💰
Price Change Alert
Monitors competitor pricing changes that affect your Buy Box position
 ⚠️
Search Suppression Alert
Fires when Amazon silently removes your listing from search results
 ⚠️
Suspended Listing Alert
Instant alert with policy notice when Amazon suspends your listing
 🛒
Add to Cart Alert
Detects when the purchase button disappears while your PPC keeps running
 📊
FBM Stock Alert
Monitors self-fulfilled inventory against your custom reorder threshold
 📊
Sales Volume Alert
Detects unexpected drops or spikes in your unit sales velocity
 💸
FBA Fee Change Alert
Flags fulfillment fee changes that hit your margins before you notice
 🖼️
Product Details Change Alert
Monitors title, bullets, and description for unauthorised edits
 🖼️
Main Image Alert
Detects when your listing's main image is swapped or removed
 🖼️
Category Change Alert
Flags when your ASIN is moved to a different browse node
 🖼️
Parent Product Change Alert
Detects when your variation's parent ASIN is changed or broken
 🏆
Best Seller Badge Alert
Monitors when you earn or lose the #1 Best Seller badge
 🏆
Amazon's Choice Alert
Alerts when you gain or lose the Amazon's Choice badge by keyword
 🔄
Subscribe & Save Alert
Detects changes to your Subscribe & Save eligibility and discount
 ⭐
Latest Reviews Alert
Every new review delivered the moment it posts — star, text, and status
 ⭐
Top Rated Reviews Alert
Monitors which reviews Amazon promotes to the featured position
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