test/live mismatch 🔌 API

API Error: a similar object exists in test mode, but a live mode key was used

You’re using an ID, key or URL from one environment (test/sandbox) with credentials from another (live/production), or vice versa.

Seen on: REST API

Meaning

Payment and SaaS APIs keep test and live data completely separate. Stripe says “No such customer: 'cus_x'; a similar object exists in test mode, but a live mode key was used to make this request”. Other providers return 401 “invalid key for this environment” or simply “not found”.

It typically happens after going live: the keys were swapped but IDs (prices, plans, webhooks, customers) saved in the database or config are still test-mode IDs — or the frontend uses a test publishable key while the backend uses a live secret key.

Common causes

  • Test-mode IDs (price, plan, product, customer) stored in config after switching to live keys
  • Frontend and backend use keys from different modes
  • Sandbox base URL with production credentials (or the reverse)
  • Data copied from staging to production

⚡ Quick fix

  1. Use keys and IDs from the same mode everywhere
  2. Recreate products/prices/webhooks in live mode and update stored IDs
  3. Keep mode-specific settings in per-environment config

Detailed fix by platform

Node.js

  1. javascript
    // fail fast if keys from different modes are mixed
const live = process.env.STRIPE_SECRET_KEY.startsWith('sk_live_');
if (live !== process.env.STRIPE_PUBLISHABLE_KEY.startsWith('pk_live_')) throw new Error('Stripe keys are from different modes');

How to diagnose

  1. Keys — Prefixes of secret and publishable keys (sk_live/sk_test)
  2. IDs — Where were stored IDs created?
  3. URLs — Sandbox vs production base URL

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