How is this different from Stripe CLI?

Stripe CLI replays happy-path events officially and well. Finxture runs deterministic failure sequences — duplicates, reordering, omissions — with verdicts about your app's behavior. They complement each other.

The extension is free. A paid cloud sandbox with consistent API state is planned.

Stripe-compatible today. The canonical scenario model is provider-neutral by design.

Synthetic test data only, localhost-only delivery, and the extension visibly discourages production endpoints.

Chrome extension · free

Test the payment failures your provider's sandbox can't.

Finxture runs deterministic payment scenarios — duplicates, retries, out-of-order webhooks — against your localhost. Signed like the real thing. No magic amounts. No ngrok.

Coming soon to the Chrome Web StoreBrowse scenarios ↓

Your checkout is hosted by your provider and your backend consumes webhooks? You're exactly who this is for.

payment-succeeds.run

[x] signature accepted
[ ] awaiting retry
[!] duplicate processed twice

Provider sandboxes are built for the happy path.

[ ]duplicate webhook delivery
[ ]out-of-order events
[ ]a webhook that never arrives
[ ]retry after your 500
[ ]a fraud decline — no magic amount exists for it

Magic test amounts encode outcomes into payloads. Your test suite shouldn't depend on 4000 meaning “declined”.

How it works

1Install the extension
2Point it at your localhost webhook endpoint
3Pick a scenario and run

Finxture ──signed webhook──> localhost:3000/webhooks/stripe

Everything stays on your machine. The extension talks only to the endpoint you configure.

Scenario catalog

[x]Payment succeeds (available)
[ ]Duplicate delivery (coming soon)
[ ]Declined payment (coming soon)
[ ]Retry after non-2xx (coming soon)
[ ]Out-of-order delivery (coming soon)
[ ]Delayed delivery (coming soon)
[ ]Refunds (coming soon)
[ ]Disputes (coming soon)

We tell you what should happen on your side.

[x]acknowledged with 2xx
[x]second delivery treated as no-op
[!]charge recorded twice

Every scenario ships with the checklist of what your application must do — and verifies what it can observe.

We can't see your data. By design.

Webhook bodies and secrets never leave your machine.
Requests go only to the localhost endpoint you configure.
No accounts, no payload collection.

Read the privacy policy →

What's next

Consistent API state + webhooks, no tunnels — in development.

Scenario updates will be announced here — subscription coming soon.

Frequently asked questions

How is this different from Stripe CLI?: Stripe CLI replays happy-path events officially and well. Finxture runs deterministic failure sequences — duplicates, reordering, omissions — with verdicts about your app's behavior. They complement each other.
Is it free?: The extension is free. A paid cloud sandbox with consistent API state is planned.
Which providers?: Stripe-compatible today. The canonical scenario model is provider-neutral by design.
Is it safe to use?: Synthetic test data only, localhost-only delivery, and the extension visibly discourages production endpoints.