Four Layers On One Swipe, The 9 Percent I Actually Keep

Most cashback guides tell you to switch banks, download a portal and call it a day. That gets you 2 percent on a good month. I wanted more and I had a year to test. The setup I landed on pushed my effective cashback to 9.1 percent across the spending I would have done anyway. Here is the exact stack, what each layer contributes, and what I had to stop doing.

The four layers, in the order they stack

  1. Reward credit card: base 1 percent on everything, 3 percent on groceries, 2 percent on fuel. My workhorse is an American Express Gold routed through a neobank account for the cash ceiling.
  2. Cashback portal: iGraal for French online orders, TopCashback for UK retailers. Average 4 to 6 percent on eligible stores, occasional 10 percent events.
  3. Merchant promo: the 5 euro off 50 euro type codes that sit on Poulpeo and in newsletter welcome flows. I only use them on purchases I was already going to make that week.
  4. Return credit card: a secondary card with a 3 percent bonus on one rotating category. I use it exclusively for that category and nothing else.

The stacking math matters. Each layer applies to the transaction, not to the previous layer, so four layers of 2 percent stack to 8 percent, not 1.08 to the fourth power. The portals need the browser extension active at the moment of purchase, and the return card has to clear before the statement cycle; miss either and the stack drops to two layers.

What the 2025 numbers looked like

Across 18,400 euros of eligible spending last year, the four layers returned 1,680 euros. Groceries were the biggest single line, 6,100 euros with a blended 7.4 percent return. Online orders on iGraal eligible stores pulled 2,800 euros at a 9.8 percent blended return. The headline 9.1 percent is a weighted average; non eligible spending like rent and public transport sat outside the stack entirely and was excluded from the denominator.

The discipline that made the number hold is boring. I did not buy anything I did not already need. A 10 percent cashback on a 400 euro gadget I did not want is a 360 euro loss. The whole point of this stream, like every entry in the passive income hub, is that it sits on top of life that was already happening. The same logic applied to bandwidth apps on a laptop already running and to a storage node on a machine already powered.

Where the stack breaks

Portals occasionally fail to track a purchase; I lost 38 euros of expected cashback on iGraal in March because a VPN reset my session mid checkout. I now always check out from a clean browser profile with no VPN active, no extension other than the portal, and a manual click through from the portal within five minutes of adding to cart. Tracking disputes are winnable when you have the order reference and timestamp.

John's rare tip

Chain a gift card through the portal

My highest yield move was buying an Amazon gift card through iGraal at 3 percent, then using it on Amazon during a portal promo day at 8 percent, stacking to roughly 11 percent on the same euro. Not every portal allows this, the terms change monthly, and it only works on stores that accept third party gift cards. Check the fine print each time.

What I'd avoid

Do not chase sign up bonuses on cards you will not keep. Annual fees kill the ROI on a 150 euro welcome gift by month ten, and the credit enquiry hurts your score for a year. I opened two cards in 2023 for bonus hunting and net lost 40 euros once the fees and admin time were counted. Stacking on cards you already pay for is the only clean path.

Frequently asked

Is 9 percent really sustainable every month?

No, it is a twelve month average. My best month hit 14 percent because a home appliance purchase triggered a 10 percent portal bonus on top of the base layers. A normal month sits between 6 and 8 percent. The point of stacking is lifting the floor, not chasing a single big month.

Does cashback stacking work outside of the euro zone?

The principles do, the specific portals do not. In the UK the Chase Rewards stack plus TopCashback matches my euro zone setup. In the US the Rakuten plus portal card combo is even more generous. In France, Igraal and Poulpeo are the portals that still route properly; iGraal pays the fastest.

What counts as income for tax purposes?

In France cashback on personal purchases is generally not taxable because it is treated as a rebate on the sale price. Sign up bonuses paid in cash can be treated as miscellaneous income above a threshold. I keep a spreadsheet and ask my accountant; rules change yearly.