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+# Stripe account Test mode and sandboxes
+
+Stripe's new-account onboarding can expose two distinct test environments:
+
+- The account's classic Test mode keeps the main account ID and uses URLs shaped
+  like `https://dashboard.stripe.com/{account_id}/test/...`.
+- Choosing **Go to sandbox** during onboarding can create an additional sandbox
+  with its own account ID and API keys.
+
+Do not assume that the environment opened by the onboarding flow is the main
+account's Test mode. Before creating products, prices, or webhooks:
+
+1. Read the account ID from the URL.
+2. Open `/{main_account_id}/test/apikeys`.
+3. Verify the API key by retrieving `/v1/account` and comparing its `id` with
+   the intended main account ID.
+
+Useful stable routes:
+
+- `/{account_id}/test/apikeys` — Test mode API keys
+- `/{account_id}/test/settings/account` — account display name
+- `/{account_id}/test/settings/payment_methods` — payment method configuration
+- `/{account_id}/test/settings/tax` — Stripe Tax settings
+
+The initial **Business name** onboarding field can replace the display name
+shown in the account switcher. Restore a product-specific display name under
+**Settings → Business → Account details** if the legal name makes sibling
+product accounts indistinguishable.