Free tool

How much revenue are you leaking?

Three leaks cost subscription businesses money without a single alert: payments that failed and were never collected, cards that are about to stop working, and people who quietly cancelled. Paste a read-only Stripe key and see your own three numbers. Totals only, no signup to see them.

At a glance. For a founder who bills through Stripe and wants the real figures. It reads failed payments, cards about to expire and cancellations from your own account with a read-only key, and returns totals. Stripe only for now; totals, never customer names; test-mode keys see no real payments. Last checked 13 November 2026.

Make the key in two minutes

Open dashboard.stripe.com/apikeys in live mode (a test-mode key sees no real payments).
Press Create restricted key and name it FoxPlug scan.
Set these rows to Read: Customers, Charges and Refunds, Subscriptions, Invoices, Events, Disputes, Products and Prices, Customer portal, Subscription schedules. Leave every other row on None. Never choose Write.
Press Create key, confirm the code Stripe sends you, copy the key that starts rk_live_ (Stripe shows it once) and paste it above.

These are the same nine rows the FoxPlug app asks for, so the same key works there later. Stripe's own page on keys: docs.stripe.com/keys.

What the three numbers mean

Failed payments still unpaid. Invoices created in the last 90 days that Stripe tried to charge and that are still open (at least one failed attempt) or marked uncollectible. An invoice that failed once and was then paid is recovered money, so it is not counted.
Cards expiring in 60 days. Active subscriptions whose default card expires within the next 60 days (a card works through the last day of its expiry month). The amount is their monthly price: yearly plans divided by 12.
Cancelled in 90 days. Subscriptions cancelled in the last 90 days, and the monthly price they were paying.

The scan reads up to the newest 500 open invoices, 500 active subscriptions and 300 cancelled ones; if your account is bigger it says so and the totals are a floor. Amounts in different currencies are kept apart, never converted. The "what could come back" lines are what-ifs at 10%, 25% and 50% of the unpaid failed amount: you choose the rate, nobody can promise it. Stripe describes how its automatic retries work on its Smart Retries page.

What it never does: write to Stripe, read a customer's name or email, keep your key, or show a customer anywhere. The result lists counts and money only.

Questions

Is it safe to paste a Stripe key?

Only paste a restricted key set to Read. The scan refuses a key that can write, a full secret key and a test-mode key. The key is used for read-only requests in one call and is not stored, cached, logged or returned, and the page clears the box as soon as the answer arrives. If you would rather not paste a key, the calculators on this site work from numbers you type.

What does it cost?

The scan is free. Acting on what it finds (notes to people whose card failed or is about to expire, win-back messages, sending) is on the paid plans; see the pricing page.

Does it work with Lemon Squeezy or Paddle?

The scan reads Stripe. FoxPlug also reads Lemon Squeezy and Paddle inside the app, and the three calculators work for any payments tool.

More free tools: all tools. Where to find the connect steps for your payments tool: Stripe, Lemon Squeezy, Paddle.