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Testing your integration
Three ways to test, from fastest to most faithful. Most teams use all three.
1. Your TenkeyBridge sandbox
Every organization has one. It answers the full API from a sample company (ExampleCo Landscaping), resets in a second, and needs no QuickBooks. Use it while you build and in CI. See Sandbox for what it covers, its fixed record ids and its limits.
2. An Intuit developer sandbox (QuickBooks Online)
If you also support QuickBooks Online, a free Intuit developer account at https://developer.intuit.com gives you QuickBooks Online sandbox companies. Point the same code at Intuit's sandbox and at your TenkeyBridge sandbox to compare the two side by side; the playground does exactly that for common requests.
3. A real QuickBooks Desktop company file
For full fidelity (reports, your customer's own data, Desktop-side behaviour), connect a real company file. A QuickBooks Desktop trial works. Create a regular realm in the portal and connect it over the Web Connector; nothing to install beyond QuickBooks.
Keep the sandbox and the real realm on separate OAuth clients (or at least separate tokens) so a test run never writes to real books.

