Help & Documentation

Endpoint: POST https://api.rowsink.com/v1/spreadsheets/:uuid/rows

Headers: Content-Type: application/json. If the configuration has API key protection enabled, also send Authorization: Bearer YOUR_KEY_SECRET or Authorization: RowsinkKey YOUR_KEY_SECRET.

Body: A JSON object or array of objects. Keys become column headers; values become cell values. Empty body or non‑JSON returns 400.

Success response (200): { "success": true, "data": { "rowsQueued": N } }. Rows are queued and written to the sheet asynchronously. "Queued" means accepted; they are processed shortly after.

Error responses: 400 (invalid format / no data), 401 (missing or invalid API key when required), 404 (unknown UUID), 413 (body too large), 429 (rate limit exceeded). Response body includes an error message.

Rate limits: 100 requests per minute per IP and 100 per spreadsheet (sliding window). Exceeding either limit returns 429 with Retry-After (seconds). Responses also include X-RateLimit-Limit and X-RateLimit-Remaining.

Request body: Must not exceed 200 KB. Larger payloads return 413 with "Request body must not exceed 200 KB".

• Columns: JSON keys are collected from your payload to form column headers. We use the union of all keys across all objects in the request.See why this matters vs other tools →
• Nested Objects: Nested objects are automatically flattened using dot notation. For example, {"user": {"name": "Alice"}} becomes a column named user.name.
• Expand Nested Arrays: When enabled in settings, we create additional rows when your data contains arrays nested inside objects. A top-level list of records already appears as one row per item. However, if an object has a nested list (e.g., individual items in an order), this setting expands them into multiple rows.
• Timestamp column (optional): When enabled, RowSink writes an automatic timestamp to column A for every row.
  • Smart Mode (Default): Writes high-precision numeric values synced to your spreadsheet's timezone. Recommended for easy sorting and filtering.
  • ISO 8601 Strings: Writes timestamps as plain text (e.g., "2026-02-16T18:00:00Z"). Enable this in settings if you need strict machine-readable strings for external processing.
• Header row: Automatically managed. Rowsink writes a header row the very first time you send data. If you later send data with a different schema (new keys or different order), we automatically write a new header row before appending that data. This ensures your data always stays aligned with its corresponding headers without manual configuration.
• Values: null / undefined → empty cell. Objects and arrays (if not expanded) are stringified as JSON.
• Formula Escaping: Values starting with +, =, -, or @ are prefixed with a single quote (') so Google Sheets treats them as plain text instead of formulas.

For each spreadsheet you can enable API key protection. When enabled, each request to send data must include a valid API key in the Authorization header.

Create a key: In the spreadsheet configuration, open the API Key section and click "Create API Key". The secret is shown only once—copy and store it securely. You can regenerate (revokes the old key) or revoke keys at any time.

Authorization: Use Bearer <secret> or RowsinkKey <secret>. Keep the space after "Bearer" or "RowsinkKey". The secret is the value you received when creating the key (it starts with rk_live_).

• Header row: Automatically managed based on your data schema. No manual reset is required.
• Add timestamp column (column A): When on, each new row gets an automatic timestamp in column A. By default, these are "Smart" numeric values that respect your spreadsheet's timezone for perfect sorting.
• Expand Nested Arrays: When on, nested arrays in your JSON objects are expanded into additional rows. See section 4 for details.
• API key protection: Toggle whether an API key is required to send data to this endpoint.
• Edit configuration: You can change the Google Sheets URL or sheet tab. Re-check the connection after changing the URL, then save. Changing to a different spreadsheet will require access verification again.

Endpoint Tester (/tester): Select a configuration, optionally add an API key, edit a JSON payload, and send a test request. Use the load test to fire repeated requests at a chosen rate (0.1–100 req/s, 1–300 seconds) to verify behavior under load.

Queue Log (/queue-log): Live stream of Enqueued (rows added to the queue) and Processed (rows written to the sheet) events. Only events received while the page is open are shown. Useful to confirm that data is being accepted and written.

Spreadsheet Capacity Checker (/spreadsheet-capacity): Check how full your Google Spreadsheet is. Google Sheets limits each spreadsheet to 10 million cells total (across all tabs). This tool shows your current usage and breakdown by tab.

Google Sheets has a limit of 10 million cells per spreadsheet. This limit applies to the entire spreadsheet file, not per individual tab. All tabs within a spreadsheet share this 10 million cell budget.

If you try to append data that would exceed this limit, Google Sheets returns a 400 Bad Request error: "This action would increase the number of cells in the workbook above the limit of 10000000 cells." The entire append operation fails—no partial writes occur.

What counts toward the limit: Every cell in the allocated grid space, including blank cells. Google Sheets counts cells based on the grid dimensions (rows × columns), not just cells with data.

If you approach the limit: Consider archiving old data, splitting data across multiple spreadsheets, or reducing the number of columns in your sheets. Each spreadsheet file gets its own 10 million cell budget.

You can have up to 10 spreadsheet configurations per account. Delete one to add another. The dashboard and My Spreadsheets pages show how many you have in use.