Open beta — 14-day trial, then $29/mo

Recover the payments Stripe couldn’t

Hi — we built Karvox because every indie SaaS we talked to was quietly losing 5–10% of MRR to expired cards and silent declines. It catches those failures, emails your customer, and gives them a one-click way to fix their card. That’s the whole product.

No credit card needed to start. Cancel anytime.

Why this exists

The quiet churn nobody told you about

The card expires. They don’t notice.

Your customer’s card hits its expiry date. Stripe tries to charge, gets declined, retries a couple of times, then gives up. The subscription quietly ends. They never realize — until they try to log in three months later and wonder why they don’t have access.

It compounds faster than you think

5% MRR loss per month doesn’t sound terrible. But if your churn rate jumps 5 points because of failed payments alone, that’s roughly half your growth eaten before you even notice.

Stripe’s built-in retries are fine. They’re also not enough.

Smart Retries handles the charge attempt. It doesn’t email your customer, doesn’t give them a way to update their card from outside your app, and doesn’t tell you what you recovered. That last 30% — the human part — is what Karvox does.

How it actually works

The whole loop, end to end

Hook it up to Stripe

One OAuth click. Stripe Connect handles everything — we never see card numbers, you can disconnect any time.

We listen for failures

Every invoice.payment_failed webhook hits our endpoint. We log it, figure out which customer it’s for, and start the sequence.

Your customer gets an email

Friendly tone, your branding, your company name. One button: “Update my card.” If they don’t click in 48h, they get a softer follow-up. If they still don’t, a final note at day 7.

They fix the card, you get paid

The button opens a hosted page (no login needed) where they swap in a new card. Stripe re-tries the failed invoice automatically. Subscription stays alive. You see it flip to “recovered” on your dashboard.

See it in action

A real recovery sequence

Mar 1, 09:14 AM

Payment failed — $49.00 charge declined (card expired) for customer alex@startup.io

Mar 1, 09:15 AM

Email #1 sent — Friendly reminder with one-click card update link

Mar 3, 10:00 AM

Email #2 sent — Gentle follow-up: "Your subscription is at risk"

Mar 3, 02:38 PM

Card updated — Customer updated payment method via recovery page

Mar 3, 02:39 PM

Payment recovered — $49.00 charged successfully. Subscription active.

$49.00 recovered

Customer retained — no manual work required

Pricing

One price. One thing it does well.

Pays for itself the first time it catches a $30 subscription. After that, it’s free money. (Well, $29/mo.)

Karvox

For indie SaaS that don’t want enterprise dunning bills

$29/mo

14-day free trial · cancel anytime

One-click Stripe Connect setup
3-email recovery sequence (yours to customize)
Hosted card-update page (no customer login)
Dashboard showing what’s been recovered
Your branding on every email
No platform tax — we don’t take a cut of recovered revenue

Bigger plans coming when there’s a reason for them. For now, one tier keeps things honest.

Things people actually ask

Who should not use this?

If you’re past ~$50K MRR, you probably want a fancier dunning tool — Churn Buster, Stunning, or Paddle Retain all do more than we do (and charge more for it). If your subscription product takes one-off payments instead of recurring ones, Karvox doesn’t help. And if you only have a handful of customers, the math doesn’t work — losing a payment hurts but the cost of a tool to recover them might be more than what you’d save.

How is this different from Stripe Smart Retries?

Smart Retries handles the charge attempt — retry on Tuesday, Friday, etc. Karvox is everything Stripe doesn’t do: emails your customer about the failure, gives them a one-click way to swap their card (no app login), and tracks which charges came back. The two are complementary, not competing.

How long does setup take?

Realistically, under 10 minutes. Sign up, click “Connect with Stripe,” finish the OAuth flow on Stripe’s side, and you’re live. The first time a charge fails, we’ll process it. You can customize the email subjects and timing later in /templates.

Do you take a cut of recovered revenue?

No. Flat $29/mo, whether we recover $20 or $20,000 for you. That alignment matters to us — the goal is to be worth keeping, not to grow only when you grow.

Is my customers’ payment data safe?

We use Stripe Connect, so card numbers never touch our servers — they live inside Stripe’s PCI environment the whole time. The card-update page uses Stripe Elements, which means even on our hosted page, Stripe handles the sensitive bits directly.

What if I’m on Paddle or LemonSqueezy instead of Stripe?

Stripe only for now — we wanted to make one integration really good before adding more. If you’re on Paddle or LemonSqueezy and would actually pay for this, email us (the button at the top) and we’ll move it up the list.