Shadow Mode: Test Your Integration Before Going Live

Shadow mode is a test period in which a newly set up marketplace integration reads for one to two weeks and writes nothing. The system watches orders, stock, and prices, compares the values it computes with the real ones, and once the numbers reconcile, write access is handed over channel by channel. At Bulutegra this is not optional; it is the third step of setup. This article explains the rule, how the process runs, and what the handover decision is based on.

Why a read-only period is necessary

The riskiest days of any integration are the first ones. A matching error nobody noticed turns, within hours on a live system, into wrong stock, wrong prices, and cancelled orders. A product sold at the wrong price cannot be taken back; a product showing zero stock misses the sale day.

Shadow mode removes that risk. The system works with real data but shows its results only in its own panel. You compare the value the system says it "would have written" with the actual value. No difference means confidence; a difference means a cause to find. That is why Bulutegra's setup runs in four steps: Connect, Match, Observe, Hand over. Shadow mode is the Observe step; the full sequence is in the four-step setup guide.

Rule: before the system makes decisions for you, it must prove it makes the same decisions you would.

What the system does and does not do in shadow mode

What it does:

• Pulls orders from every channel and lists them in the panel.
• Reads stock from your catalog source and ERP, and computes the stock it would write per channel.
• Computes the price per channel from the price matrix.
• Reads the actual stock and price on each channel listing.
• Compares computed values with actual values and reports differences.
• Runs channel monitoring; a silent channel raises an alert.

What it does not do:

• Writes no stock to any channel.
• Writes no prices to any channel.
• Sends no order status, shipping data, or return records.
• Writes no orders to your ERP (it can preview them in a test view if you want).
• Changes nothing in your current setup; your old integrator or manual process keeps running.

Shadow validation step by step

The process starts once product matching is complete. The order is:

1. Take a baseline. Record stock and price for a sample of products on every channel and in the source; this is your first comparison point.
2. Switch on shadow mode. Write access is off for all channels; read access is on.
3. Review differences daily for the first three days. The panel shows "computed" next to "actual"; list the products with a gap.
4. Classify the causes. Three typical ones: a matching error, a manual change on the channel, or a delay between ERP and catalog.
5. Fix matching errors. As soon as a wrongly linked variant is corrected, the gap should close. Matching rules are in product matching with SKU and barcode.
6. Validate order flow. Confirm that every order visible on the channel appears in the panel with the same line items and totals.
7. Get through a weekend. Order volume and stock movement differ at weekends; see that the system computes correctly on those days too.
8. In week two, reduce daily checks to sampling. If random products show zero difference, confidence is established.
9. Decide per channel. A channel whose gap has reached zero is ready for handover; a channel with a persistent gap stays in shadow mode.
10. Set the handover order. Start with the lowest-volume channel and leave the highest-volume one for last.

When the numbers reconcile: channel-by-channel handover

Handover is done "one channel at a time", never "all at once". The reason is simple: if something goes wrong on one channel, only that channel is affected and it is easy to roll back. The sequence usually runs like this:

• First handover: the lowest-volume channel. If a problem appears, its impact is small.
• On the first handover only stock writing is enabled; price writing follows a day or two later.
• Difference checks continue for two days on the handed-over channel.
• If there is no gap, move to the next channel.
• The highest-volume channel (for many sellers Amazon, or Trendyol in Türkiye) comes last.
• On every handover the ownership flag is updated: for product × channel, "this channel is managed by Bulutegra" is set and the old system's write access on that channel is turned off.

Never let the old system and the new one write to the same channel at the same time. The ownership flag exists for exactly this: one channel, one manager.

Handover checklist

Before handing over a channel, every item below must be a "yes":

• Has the gap between computed and actual stock been zero for the last three days?
• Has the price gap been zero for the last three days?
• Did every order on the channel appear in the panel with matching totals?
• Is the unmatched product count zero, or deliberately out of scope?
• Is the ownership flag set correctly for this channel?
• Has the old system's write access on this channel been turned off?
• Has the channel monitoring alert been tested; did the notification reach a phone?
• Is the rollback path known (turn off write access, return to the old system)?

If any answer is "no", the channel stays in shadow mode for another day or two. That is not a delay; it is insurance.

What you learn in shadow mode

Shadow mode does more than find errors; it shows you your own business data. Two weeks of observation reveal the order rhythm per channel, which products drop to critical stock, and on which channel prices disagree with the source. Those findings help you set the thresholds for low-stock alerts and the days-of-stock report after handover; see critical stock and days of stock.

Whether an integrator offers this step at all is a selection criterion in its own right; in 15 questions to ask before choosing an integrator, question seven is exactly this.

How this works with Bulutegra

In Bulutegra, shadow mode is the third step of setup and is never skipped. When matching is complete, the system reads only, for one to two weeks; the Integration Panel shows computed and actual values side by side and lists the differences. When the numbers reconcile, write access is enabled channel by channel, stock first and then price, and the ownership flag is updated on each handover. The software ran under this rule inside the founding company's own retail operation before it was offered to others, so the process is field-tested. To see how it runs on your channels, request a demo.