DunningKit

Open-source toolkit for analyzing and recovering failed Stripe payments.

A pragmatic toolkit for B2B SaaS teams who want to recover the ~50–70% of failed Stripe charges that Smart Retries doesn't catch. Reads your Stripe failed-charge data, surfaces the recoverable portion by decline code, and generates the retry sequences + customer-facing flows that actually convert.

Status: v0.0.1 (CSV analysis + recovery-rate library). Live Stripe API integration and hosted recovery dashboard ship in summer 2026. Public landing at https://dunningkit.quantcalc.app.

Why

Stripe Smart Retries is good but limited. It picks decent retry timing for insufficient_funds and a handful of common decline codes, but it doesn't:

• Email your customer when their card expires (the single largest recovery lever)
• Handle the long-tail decline codes (do_not_honor, card_velocity_exceeded, authentication_required) well
• Give you visibility into what's recoverable vs already lost

The middle ground between "Stripe defaults" and a $99–$299/month recovery service has been thin for a while. DunningKit is the open-source layer that fills it.

Quick start

pip install dunningkit

Export your failed charges from Stripe Dashboard → Payments → filter by Status: Failed → Export to CSV.

$ dunningkit analyze stripe-failed-charges.csv

Period: 2026-04-01 to 2026-04-30
Failed charges: 142 totalling USD 14,820.00

Decline-code breakdown (sorted by frequency):
  insufficient_funds   38       USD 3,940.00  ~      USD 2,955.00 recoverable
  expired_card         31       USD 3,210.00  ~      USD 2,728.50 recoverable
  do_not_honor         22       USD 2,290.00  ~      USD 1,145.00 recoverable
  generic_decline      18       USD 1,870.00  ~        USD 748.00 recoverable
  ...

Recovery summary:
  Retries only          ~      USD 5,520.00  (37% of total)
  + Customer flows      ~      USD 8,420.00  (57% of total)

  Customer flows add ~USD 2,900.00 of recovery on top of retries alone.
  This is the dunning opportunity Stripe Smart Retries doesn't capture.

For machine-readable output:

dunningkit analyze --json stripe-failed-charges.csv

What's in this v0.0.1

• CSV analyzer that reads Stripe Dashboard exports and reports the recoverable portion of failed charges, broken down by decline code.
• Recovery-rate library with aggregate estimates per decline code (insufficient_funds recovers ~70% on retries; expired_card recovers ~5% on retries but ~85% with a card-update flow; etc.).
• Pure stdlib — no runtime dependencies. Python 3.11+. Works offline; doesn't connect to Stripe or any other service.

What's coming in v0.1

• Live Stripe API connection (read failed charges directly without CSV exports)
• Per-code retry sequence executor
• Customer-facing card-update flow generator (Stripe Customer Portal session creation)
• Email/SMS template library with brand variables
• Recovery-attribution dashboard (what we recovered vs what Stripe Smart Retries got)

License

Apache-2.0. See LICENSE.

The CLI and recovery-rate library are open source. The hosted recovery dashboard, live Stripe integration, automated retry sequences, and team workflow features are commercial.

Background reading

• What Stripe Smart Retries actually does (and what it doesn't)
• Failed-payment recovery rates by Stripe decline code
• Dunning emails for B2B SaaS: timing, tone, anti-patterns
• Card-update flows that actually convert
• Annual subscriptions and failed payments — the harder game

Contributing

Issues and PRs are welcome; please file an issue before sending a substantial PR so we can align on direction.