PayloadFlatten is a zero-server Google Sheets™ add-on designed to unpack, un-nest, and flatten nested JSON webhooks and API payloads directly into structured spreadsheet rows and columns.

### Key Features
- **=FLATTEN_JSON(range, delimiter)**: Converts any nested JSON payload into flat key-value columns with dot notation (e.g., customer.billing.address).
- **=FLATTEN_JSON_ROWS(range, list_path, delimiter)**: Automatically expands repeated JSON arrays (such as Shopify line_items, Stripe invoice items, or Make/n8n batches) into one clean row per item, while keeping parent order metadata synchronized across every row.
- **Smart Data-Type Preservation**: Automatically casts decimal price strings (e.g., "149.99") into real spreadsheet numbers so formulas like =SUM(), =AVERAGE(), and pivot tables work immediately without formula errors.
- **100% Client-Side Privacy**: Runs completely within your browser sandbox via Google Apps Script. Zero external servers. Your webhook data and spreadsheet records never leave your Google account.

### How to Use
1. Paste your JSON webhook or API response into any cell (e.g., cell A2).
2. In cell B2, enter the formula:
   =FLATTEN_JSON_ROWS(A2:A10, "line_items")
3. Press Enter. PayloadFlatten automatically unpacks the line items into structured columns and rows.
4. Optional: Use the Extensions > PayloadFlatten menu to flatten selected columns or activate Pro features.