SheetCapture API

1. 1

   Create a Google Sheet

   Any sheet works. Rows go into the first tab, and if it has no header row yet we create one from the first row you send.

2. 2

   Share it with our API email

   Click Share in Google Sheets and add this address as an Editor. Your sheet stays private to everyone else.

   sheetcapture@appspot.gserviceaccount.com
3. 3

   Copy your Sheet ID

   It's the long ID in your sheet's URL:

   docs.google.com/spreadsheets/d/YOUR_SHEET_ID/edit

4. 4

   Send a request with your access key

   Your access key is on your account page once you sign up. The free trial includes 20 requests a month.

   Get your access keyLog in

Send your access key in an Authorization header with every request. You can always find it on your account page.

Authorization: Bearer YOUR_ACCESS_KEY

HTML forms can't set headers, so for forms send it as a hidden AccessKey field instead (see the HTML form example).

Appends a row to the first tab of your sheet. Each key in data is a column header and its value goes in that column.

• Keys are matched to your existing headers ignoring case, so email fills an Email column.
• A key with no matching header gets a new column added at the end. Columns you don't send are left empty.
• A date column is always filled with the time we received the row, formatted as d/m/yyyy h:mm (for example 14/3/2026 9:05).
• Values are stored exactly as sent. Objects and arrays are saved as JSON text.

Headers

Request body

Sending form data? HTML forms can't nest fields or set headers, so add hidden GoogleSheetID and AccessKey fields. Every other field becomes a column.

Add a hidden _redirect field with a full URL to send visitors to your own thank-you page after they submit, instead of showing the JSON response. If something goes wrong, they're still redirected, with ?sheetcapture_error= and the error code added to the URL, so your page can show a message.

Limits

• Up to 50 columns per row.
• Column names up to 100 characters, not starting with =, +, - or @.
• Values up to 50,000 characters (Google Sheets' cell limit).

Replace YOUR_ACCESS_KEY and YOUR_SHEET_ID with your own.

const response = await fetch("https://www.sheetcapture.com/add-row", {
  method: "POST",
  headers: {
    Authorization: "Bearer YOUR_ACCESS_KEY",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    GoogleSheetID: "YOUR_SHEET_ID",
    data: {
      Name: "Ada Lovelace",
      Email: "ada@example.com",
      Message: "Hello!",
    },
  }),
});

if (!response.ok) {
  const { error } = await response.json();
  console.error(error);
}

The HTML form posts directly to the API, then sends visitors to the _redirect page. Leave it out and they'll see the JSON response instead.

Successful requests return true. Errors return a JSON object with a readable error message and a stable code you can check in your code:

{ "error": "Google Sheet not found. Check GoogleSheetID…", "code": "sheet_not_found" }

Any request that fails after authentication, including Google errors, is refunded. You only pay for rows that were written.

Usage headers

Every authenticated response tells you where you are with your allowance:

• Each successful request uses 1 request from your plan.
• Requests that fail validation (400) or authentication (401) are never charged.
• If Google Sheets rejects the write (403, 404, 422, 502 or 503), the request is refunded automatically.
• Your allowance refills to the full amount every month, on the day of the month you signed up.
• Once your allowance runs out, requests return 402 until it refills, or until you upgrade.

The API accepts requests from any origin and answers OPTIONS preflight requests, so you can call it straight from the browser or from your own server.

403 sheet_not_shared

Share the sheet with sheetcapture@appspot.gserviceaccount.com as an Editor. Viewer or Commenter access isn't enough.

404 sheet_not_found

Copy the ID again from your sheet's URL: it's the part between /d/ and /edit.

401 Invalid AccessKey

Copy the access key again from your account page. It's case sensitive.

402 No requests remaining

You've used this month's allowance. It refills on your monthly reset date (shown on your account page), or upgrade your plan for more.

A new column appeared instead of filling an existing one

Keys are matched to headers ignoring case, but otherwise must match exactly, including spaces. E-mail and Email are different columns.

My date field is missing

date is reserved: it's always set to the time we received the row. Use a different name, like event_date.

My value shows as text instead of a formula

Values are always stored exactly as sent, so submitted text can never run as a formula in your sheet.

Only the first sheet is written to

Rows are always added to the first tab in the spreadsheet. Drag the tab you want to the front.