Apparently, I can write to google sheets just using a URL

You're on the right track, but the mechanism isn't a direct HTTP POST to a standard Google Sheets URL. Instead, you leverage Google Apps Script to create a web application that receives HTTP POST requests and then writes the data into your Google Sheet.

Here's a breakdown of how it works:

1. Google Apps Script:

• You write a script within Google Sheets (Tools > Script editor).
• This script will contain a function that is designed to:

• Accept HTTP POST requests.
• Parse the data sent in the request (e.g., as JSON or form data).
• Use the Google Sheets API (within Apps Script) to write this data into the desired sheet and cells.

• Crucially, you then deploy this script as a web application. This process generates a unique URL that acts as the endpoint for your HTTP POST requests.

2. HTTP POST Requests:

• From your program (using any language that can make HTTP requests, like Python with requests, JavaScript with fetch, etc.), you send an HTTP POST request to the URL generated by your deployed Google Apps Script.
• The data you want to enter into the Google Sheet is included in the body of the POST request. You can format this data in various ways, commonly as JSON or URL-encoded form data.

Why not a direct POST to the Google Sheets URL?

• Security and Permissions: Directly posting data to a standard Google Sheets URL would bypass any security or permission controls. Anyone could potentially write data to your sheet. Google Apps Script allows you to control access and execution permissions for your web app.
• Data Handling and Formatting: Google Sheets expects data to be formatted in a specific way within its grid structure. A direct POST wouldn't inherently know how to interpret arbitrary data and place it correctly in rows and columns. Apps Script provides the logic to parse the incoming data and use the Sheets API to write it in the desired format.
• Logic and Processing: You might want to perform some actions on the incoming data before writing it to the sheet (e.g., data validation, formatting, calculations). Apps Script allows you to implement this logic.

In summary:

You don't directly POST to a Google Sheets URL. Instead, you:

1. Create a Google Apps Script that handles POST requests and writes to your sheet.
2. Deploy this script as a web application to get a unique URL.
3. Send HTTP POST requests to this generated URL from your program, with the data you want to enter in the request body.

This approach provides a secure and controlled way to programmatically write data to Google Sheets using HTTP POST requests. You'll need to write the Apps Script code to handle the incoming data and interact with the Google Sheets service.