Finxture

Finxture is a payment sandbox for localhost: run deterministic payment-provider scenarios and webhooks without ngrok.

Finxture is a free Chrome extension: a payment sandbox that sends realistic, signed Stripe test webhooks to a localhost or 127.0.0.1 endpoint you configure — no ngrok, no inbound tunnel, no account or cloud connection required. WHAT IT DOES - Pick a scenario from a reviewed catalog of Stripe webhook flows and run it against your own local server. - Every event is signed with a locally generated, test-only Stripe webhook signing secret, computed the same way your production verifier expects (Stripe's v1 HMAC scheme). - A durable run timeline survives Chrome closing the extension's background worker mid-run: in-flight deliveries resume, and you can replay a failed delivery attempt after your server returns a non-2xx response. - Every run ends with a report card — "Your application should…" — listing automatic checks (verified from the delivery outcomes) and manual checks (for behavior Finxture can't observe directly, like idempotent state updates), so you can see at a glance whether your webhook handler did the right thing. - Export a run as JSON: a full export for your own debugging (includes the signing secret — not for sharing), or a redacted export with credentials, signatures, and response bodies stripped, safe to attach to a bug report. SCENARIOS IN THIS RELEASE - Payment succeeds — an authorization-success event followed by a payment-success event, in order, exactly once. - Duplicate payment webhook — reuses the successful-payment flow and delivers the same logical payment-success event twice with independently valid signatures, so you can verify your handler processes duplicate webhook deliveries idempotently (a real Stripe behavior, since Stripe's own docs describe at-least-once delivery). Coming soon (not yet runnable in this release): Declined payment, Requires customer action. WHAT THIS IS NOT This is a local development sandbox, not a Stripe emulator or a certified Stripe integration. It does not claim complete Stripe API or webhook coverage, does not talk to Stripe's servers, does not process real payments, generates no real cardholder data, and is not intended for production traffic, live credentials, or production endpoints. "Stripe" is used here only to describe the webhook shapes Finxture reproduces for local testing — Finxture is not made, certified, or endorsed by Stripe. PRIVACY Your endpoint configuration, signing secret, and run history stay in Chrome's local extension storage on your device and are never uploaded. The only optional exception is consent-based product telemetry: after an explicit, itemized first-run consent screen (on by default, changeable anytime in settings), Finxture may send up to four coarse usage counters (install, endpoint configured, first successful run, run completed) to our EU-hosted analytics processor — never webhook bodies, secrets, endpoint URLs, or response content. Full details: https://finxture.dev/privacy Requires only two Chrome permissions (storage, side panel) plus optional, runtime-granted access to the one loopback host (localhost or 127.0.0.1) you choose. No `host_permissions` for arbitrary websites, no content scripts.