Stripe API Emulator

Fully stateful Stripe API emulation. Customers, products, prices, checkout sessions, payment intents, charges, and payment methods persist in memory. Webhooks fire on state changes. The hosted checkout UI lets you complete payments in the browser.

No real payments are processed. Every Stripe SDK call hits the emulator and produces realistic responses.

Start

Local listeners bind to 127.0.0.1 by default. For access from containers or other machines, pass --host 0.0.0.0 to the CLI or hostname: '0.0.0.0' to createEmulator. Configure --base-url or baseUrl for advertised URLs reachable by those clients.

# Stripe only
npx emulate --service stripe

# Default port (when run alone)
# http://localhost:4000

Or programmatically:

import { createEmulator } from 'emulate'

const stripe = await createEmulator({ service: 'stripe', port: 4000 })
// stripe.url === 'http://localhost:4000'

Pointing Your App at the Emulator

Stripe SDK

The Stripe Node.js SDK does not read an environment variable for the base URL. You must pass it when constructing the client:

import Stripe from 'stripe'

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!, {
  apiVersion: '2024-12-18.acacia',
  host: 'localhost',
  port: 4000,
  protocol: 'http',
})

Embedded in Next.js (adapter-next)

When using @emulators/adapter-next, the emulator runs inside your Next.js app at /emulate/stripe. The SDK needs to point at localhost with a proxy route to forward /v1/* calls to /emulate/stripe/v1/*:

// next.config.ts
import { withEmulate } from '@emulators/adapter-next'

export default withEmulate({
  env: {
    STRIPE_SECRET_KEY: 'sk_test_emulated',
  },
})

// lib/stripe.ts
import Stripe from 'stripe'

const port = process.env.PORT ?? '3000'

export const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!, {
  apiVersion: '2024-12-18.acacia',
  host: 'localhost',
  port: parseInt(port, 10),
  protocol: 'http',
})

// app/emulate/[...path]/route.ts
import { createEmulateHandler } from '@emulators/adapter-next'
import * as stripe from '@emulators/stripe'

export const { GET, POST, PUT, PATCH, DELETE } = createEmulateHandler({
  services: {
    stripe: {
      emulator: stripe,
      seed: {
        products: [
          { id: 'prod_widget', name: 'Widget', description: 'A useful widget' },
        ],
        prices: [
          { id: 'price_widget', product_name: 'Widget', currency: 'usd', unit_amount: 1000 },
        ],
        webhooks: [
          {
            url: `http://localhost:${process.env.PORT ?? '3000'}/api/webhooks/stripe`,
            events: ['*'],
          },
        ],
      },
    },
  },
})

// app/v1/[...path]/route.ts  (proxy for Stripe SDK)
const STRIPE_URL = `http://localhost:${process.env.PORT ?? '3000'}/emulate/stripe`

async function handler(req: Request, ctx: { params: Promise<{ path: string[] }> }) {
  const { path } = await ctx.params
  const url = new URL(req.url)
  const target = `${STRIPE_URL}/v1/${path.join('/')}${url.search}`

  const res = await fetch(target, {
    method: req.method,
    headers: req.headers,
    body: req.body,
    duplex: 'half',
  } as any)

  return new Response(res.body, {
    status: res.status,
    statusText: res.statusText,
    headers: res.headers,
  })
}

export { handler as GET, handler as POST, handler as PUT, handler as PATCH, handler as DELETE }

Direct fetch

curl http://localhost:4000/v1/customers \
  -H "Authorization: Bearer sk_test_emulated"

Seed Config

Seed data is optional. All entities support an optional id field for deterministic IDs that survive server restarts.

stripe:
  customers:
    - id: cus_demo
      email: demo@example.com
      name: Demo User
  products:
    - id: prod_tshirt
      name: T-Shirt
      description: A comfortable tee
  prices:
    - id: price_tshirt
      product_name: T-Shirt
      currency: usd
      unit_amount: 2500
  webhooks:
    - url: http://localhost:3000/api/webhooks/stripe
      events: ['*']
      secret: whsec_test

The product_name field in prices links to the product by name. Use events: ['*'] to receive all webhook events, or specify individual event types.

API Endpoints

Customers

# Create customer
curl -X POST http://localhost:4000/v1/customers \
  -d "email=user@example.com" -d "name=Jane Doe"

# Retrieve customer
curl http://localhost:4000/v1/customers/cus_xxx

# Update customer
curl -X POST http://localhost:4000/v1/customers/cus_xxx \
  -d "name=Updated Name"

# Delete customer
curl -X DELETE http://localhost:4000/v1/customers/cus_xxx

# List customers
curl http://localhost:4000/v1/customers

Products

# Create product
curl -X POST http://localhost:4000/v1/products \
  -d "name=Widget" -d "description=A useful widget"

# Retrieve product
curl http://localhost:4000/v1/products/prod_xxx

# List products
curl "http://localhost:4000/v1/products?active=true"

Prices

# Create price
curl -X POST http://localhost:4000/v1/prices \
  -d "product=prod_xxx" -d "currency=usd" -d "unit_amount=1000"

# Retrieve price
curl http://localhost:4000/v1/prices/price_xxx

# List prices
curl "http://localhost:4000/v1/prices?active=true"

Checkout Sessions

# Create checkout session
curl -X POST http://localhost:4000/v1/checkout/sessions \
  -d "mode=payment" \
  -d "line_items[0][price]=price_xxx" \
  -d "line_items[0][quantity]=1" \
  -d "success_url=http://localhost:3000/success?session_id={CHECKOUT_SESSION_ID}" \
  -d "cancel_url=http://localhost:3000/cart"

# Retrieve session
curl http://localhost:4000/v1/checkout/sessions/cs_xxx

# List sessions
curl http://localhost:4000/v1/checkout/sessions

# Expire a session
curl -X POST http://localhost:4000/v1/checkout/sessions/cs_xxx/expire

The session's url field points to a hosted checkout page at /checkout/cs_xxx. Clicking "Pay" on that page completes the session, fires the checkout.session.completed webhook, and redirects to success_url. The {CHECKOUT_SESSION_ID} template in success_url is replaced with the actual session ID.

Payment Intents

# Create payment intent
curl -X POST http://localhost:4000/v1/payment_intents \
  -d "amount=2000" -d "currency=usd"

# Retrieve
curl http://localhost:4000/v1/payment_intents/pi_xxx

# Update
curl -X POST http://localhost:4000/v1/payment_intents/pi_xxx \
  -d "amount=3000"

# Confirm (triggers payment_intent.succeeded + charge.succeeded webhooks)
curl -X POST http://localhost:4000/v1/payment_intents/pi_xxx/confirm

# Cancel
curl -X POST http://localhost:4000/v1/payment_intents/pi_xxx/cancel

# List
curl http://localhost:4000/v1/payment_intents

Charges

# Retrieve charge
curl http://localhost:4000/v1/charges/ch_xxx

# List charges
curl http://localhost:4000/v1/charges

Charges are created automatically when a payment intent is confirmed.

Customer Sessions

# Create customer session
curl -X POST http://localhost:4000/v1/customer_sessions \
  -d "customer=cus_xxx"

Payment Methods

# List payment methods
curl http://localhost:4000/v1/payment_methods

Webhooks

The emulator dispatches webhook events when state changes. Register webhooks via seed config or programmatically. Webhooks configured with a secret include Stripe-Signature: t=<timestamp>,v1=<signature>. The signature is an HMAC SHA-256 over <timestamp>.<raw body>.

Events dispatched

Event	Trigger
customer.created	Customer created
customer.updated	Customer updated
customer.deleted	Customer deleted
product.created	Product created
price.created	Price created
payment_intent.created	Payment intent created
payment_intent.succeeded	Payment intent confirmed
payment_intent.canceled	Payment intent canceled
charge.succeeded	Payment intent confirmed (charge auto-created)
checkout.session.completed	Checkout completed via hosted page
checkout.session.expired	Checkout session expired

Webhook handler example

// app/api/webhooks/stripe/route.ts
import { NextResponse } from 'next/server'

export async function POST(request: Request) {
  const body = await request.json()
  const event = body.type as string
  const obj = body.data?.object

  switch (event) {
    case 'customer.created':
      console.log('Customer created:', obj.id, obj.email)
      break
    case 'checkout.session.completed':
      console.log('Checkout completed:', obj.id)
      break
    case 'payment_intent.succeeded':
      console.log('Payment succeeded:', obj.id)
      break
    case 'charge.succeeded':
      console.log('Charge succeeded:', obj.id)
      break
  }

  return NextResponse.json({ received: true })
}

Common Patterns

Checkout Flow (embedded Next.js)

// Server action
const customer = await stripe.customers.create({
  email: 'shopper@example.com',
  name: 'Demo Shopper',
})

const session = await stripe.checkout.sessions.create({
  mode: 'payment',
  customer: customer.id,
  line_items: [{ price: 'price_widget', quantity: 2 }],
  success_url: `${origin}/success?session_id={CHECKOUT_SESSION_ID}`,
  cancel_url: `${origin}/cart`,
})

redirect(session.url!)

Retrieve Session on Success Page

const session = await stripe.checkout.sessions.retrieve(session_id)
const customer = await stripe.customers.retrieve(session.customer as string)

console.log(session.payment_status) // 'paid'
console.log(customer.name)          // 'Demo Shopper'

Payment Intent Flow (no checkout UI)

const pi = await stripe.paymentIntents.create({
  amount: 5000,
  currency: 'usd',
  customer: 'cus_xxx',
})

// Confirm triggers payment_intent.succeeded + charge.succeeded webhooks
const confirmed = await stripe.paymentIntents.confirm(pi.id)
console.log(confirmed.status) // 'succeeded'

Custom emulators alongside built-ins

Use npx emulate init --custom inventory to scaffold a third-party API emulator and test. Register it in emulate.config.ts with defineConfig from emulate, alongside built-in entries such as { emulator: "stripe" }. Run npx emulate start --watch to reload imports and inspect custom state at the printed /_emulate URL. Successful reloads reset the run to seed. Existing flat seed configs still work; --config selects an explicit file. For authoring and testing third-party API emulators, see https://emulate.dev/docs/custom-emulators.