I give every SaaS subscription its own disposable card. Here is why

TL;DR: One card per subscription caps the blast radius when a vendor leaks, a trial auto-renews, or a price quietly jumps. Virtual cards make this free.

A while back a vendor I used got breached and my card was replayed on three other sites. I spent a weekend rotating one card across every subscription I owned. Never again.

Now every recurring service gets its own virtual card. It sounds fussy. It takes about ten seconds per signup and it has saved me real money and a few bad weekends.

Disclosure: I work on Fizen, one of the virtual-card options below. The others are here because I used them first.

Why one card per service is worth it

• Kill switch. If a vendor leaks, or you hit a sticky cancellation, you delete the card and the charge dies. No support ticket.
• Trial control. Set the card to a low limit. The "we charged you $240 for the annual plan" surprise stops happening.
• Clean accounting. Each statement line maps to one tool. Reconciling spend across Cursor, Vercel, Supabase and ten others takes seconds.
• Leak isolation. A breach at one vendor cannot replay on the rest, because each has a different number.

The options

• Privacy.com. The original for this, per-merchant cards with limits. US only.
• Revolut. Disposable virtual cards that regenerate per transaction, plus normal virtual cards you can freeze. Available in many countries.
• Wise. Virtual cards you can freeze and replace, with good FX.
• Crypto-funded cards. If you already hold USDT, cards like Fizen let you spin up many virtual cards under one account and fund from stablecoins. Caveats: KYC applies, and a merchant can still block the BIN.

How I actually run it

1. New tool, new virtual card. Name it after the tool so the statement reads cleanly.
2. Set a limit just above the plan price. A surprise annual upgrade gets declined instead of charged.
3. Cancelling something painful? Delete the card first, then cancel. The renewal cannot go through.

It is the cheapest security and budgeting habit I have. What is your setup? I am curious how others isolate SaaS spend.

Longer writeup on the card side, including limits, is here.