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Your app talks to APIs you don’t own — Stripe, Twilio, GitHub, OpenAI, a bank, an agent platform. Testing against them is painful: official sandboxes are read-only or stateless, you can’t force the error cases that matter, and you can’t make time pass on demand. So most teams hand-mock and quietly drift out of sync with the real thing. ProdBreak gives you a sandbox that behaves like the real API — stateful, controllable, and faithful — that you point your app at by changing one base URL. 
// before — your app talks to the real vendor
const stripe = new Stripe(process.env.STRIPE_KEY);

// after — same app, same SDK, pointed at your sandbox
const stripe = new Stripe(PRODBREAK_KEY, { host: PRODBREAK_URL });
That’s the whole integration. Your code doesn’t change; only the address does.

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Works with any API

ProdBreak isn’t tied to one vendor. Each API is modeled once as a pack — a faithful, hand-built model of that API’s objects, lifecycle, errors, and webhooks. Point your app at the pack and it behaves like the real service.
https://www.google.com/s2/favicons?domain=stripe.com&sz=128

Stripe

https://www.google.com/s2/favicons?domain=twilio.com&sz=128

Twilio

https://www.google.com/s2/favicons?domain=github.com&sz=128

GitHub

https://www.google.com/s2/favicons?domain=openai.com&sz=128

OpenAI

https://www.google.com/s2/favicons?domain=plaid.com&sz=128

Plaid

https://www.google.com/s2/favicons?domain=shopify.com&sz=128

Shopify

https://www.google.com/s2/favicons?domain=deck.co&sz=128

Deck

…and 490 more

The promise is “any API ever.” If your app calls it over HTTP, it can have a pack. Some packs ship today, others are rolling out, and you can request one. The examples in these docs deliberately span many vendors — the control surface is identical no matter which pack you point at.

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The three things a real sandbox has to do

Stateful round-trip

What you POST comes back on the GET. Objects have a lifecycle. The sandbox is a real little database that behaves like the vendor’s, not a fixture that returns canned JSON.

Forced outcomes

Make any outcome happen on demand — the 402 decline, the rate-limit, the timeout, the failed branch of a workflow — the cases that are painful or impossible to trigger against the real vendor.

Seeding

Start from exactly the history you need. Insert objects at their final state, with deterministic, format-correct ids.
On top of those three, ProdBreak models the hard parts faithfully: webhooks that fall out of real state transitions (never fired by hand), a virtual clock you can advance, and the values a vendor returns from outside its own logic (a balance, a transcript, a score) under your control.

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Two ways to use it

The two use cases are different enough that the docs keep them separate — pick the one you’re here for.

In CI — as a testing library

Write integration tests in your normal framework (Jest, Vitest, pytest). A fixture hands you the vendor’s real SDK already pointed at a fresh world, plus a control handle to seed, force outcomes, fire events, and advance the clock. Deterministic, reset between tests, one world per worker. Start at the Quickstart, then Testing in CI.

As a live sandbox

Spin up a long-lived instance and point a real app at it like a staging environment. Same control surface, longer-lived state, wall-clock time. Good for manual exploration, demos, and front-end work without touching the real vendor. See Running a live sandbox.

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What makes it different

ProdBreak isn’t a record/replay mock or a static OpenAPI stub. The value is behavioral fidelity: a hand-modeled pack per API. That’s what lets you force a decline and have the resulting webhook, the GET, and the list all agree — because they’re all views of one real state transition. It also tells you the truth about where that fidelity ends. See How faithful is it? for exactly what we guarantee and what we don’t.
Status: pre-release. These docs describe the surface as it’s being built. Packs are rolling out vendor by vendor; examples across the docs use whichever vendor makes the point clearest, and firm up as each pack lands.
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