Editing a product later
— and why past sales don't change.

Products in nouz are designed to be edited freely — bump a price, adjust a COGS, change the tax rate — without you having to worry about breaking historical data. The reason this works safely is the snapshot pattern: every revenue entry stores its own copy of the product's values at the moment of sale.

01 The no-retroactive rule

When you log a product sale, nouz takes a snapshot of the product's sale price, COGS and tax rate at that moment. The snapshot lives on the revenue entry — not as a live pointer to the product row. Editing the product later changes the product, but every historical revenue entry keeps its original snapshot.

This means your March P&L always shows March's margins. Bumping your cappuccino price from €3,80 to €4,00 in May doesn't backdate to last month. Your March data is exactly what March was, regardless of what you do to the product row in May.

02 How to edit

1. 1
   Open Products

   You'll see the full list of your active products.

2. 2
   Click the row

   A side panel opens with the product's current values.

3. 3
   Change the fields

   Sale price, COGS, tax rate — change whatever needs changing.

4. 4
   Save

   Future sales of this product use the new values. Past sales are untouched.

03 Why we do it this way

Two reasons:

• Historical truth. Last March really was sold at €3,80, with that COGS, with that tax rate. Backdating an edit would lie about the past.
• Accounting hygiene. If your accountant ever cross-checks your P&L against an old VAT return, the numbers need to match. Live references would shift them every time you edit a product.

There's also a third reason: it makes nouz safe to use as a sandbox. You can rename, re-price, restructure your catalogue without fear that you're corrupting last month's data. That removes a huge amount of friction from running the shop.

04 When you really need to fix the past

Real cases for editing past entries: you discovered you typed COGS wrong on day one (so it's been wrong for weeks), or your supplier sent you a corrected invoice that genuinely should change your historical COGS for that batch. Both are rare. When you do need to fix the past, open the affected revenue entries individually and update their snapshot fields. Tedious for many entries; precise.