Convert Google Sheets into a REST API
Channel: Learn Google Sheets & Excel Spreadsheets

What this is: A short lesson on turning a private Google Sheet into a REST API with Google Apps Script, so external forms and services can read and write data without making the sheet public.

Who it is for
Spreadsheet creators, developers, and no-code builders who want to use Google Sheets as a backend database or API endpoint.

What you will be able to do
Set up a WORKOUTS log and a SUMMARY total, write doPost and doGet handlers, deploy the script as a web app, test writes and reads, pull the live total into another sheet, and submit entries from a simple online form.

Takeaways
1. You do not have to share the sheet or set it to “Anyone with the link.” The web app talks to the sheet while the file stays private.
2. doPost(e) is for data entry. Read URL parameters such as count and type from e.parameter, insert a new top row, and write the values.
3. doGet(e) is for reading. Fetch a cell (here, SUMMARY!B1) with getValue() and return it as HTTP text with ContentService.createTextOutput().
4. Successful writes can return an explicit HTTP 200 via ContentService.createTextOutput(200).
5. Deploy as a Web App: Execute as “Me,” Who has access “Anyone.” Authorize once.
6. After you change the script, create a new deployment so you get a working URL. The video hits a method-name typo (insertRowsBefore vs insertRowBefore) and shows this re-deploy step.
7. No-code tools such as Carrd can POST to the same URL if field IDs match the script parameters (count, type).
8. A second Google account can pull the live total with =IMPORTDATA() pointed at the GET URL.

Timestamps
00:00  Overview: turning Google Sheets into a REST API
01:13  Setting up the WORKOUTS and SUMMARY sheets
01:53  Opening Apps Script and defining doGet and doPost
02:24  Coding doPost to insert workout rows
04:44  Returning an HTTP 200 response
05:18  Deploying Apps Script as a web app
05:52  Testing POST requests with Postman
07:22  Fixing insertRowBefore and redeploying
08:31  Coding and deploying doGet to return total pushups
10:13  Fetching API data with =IMPORTDATA() in another sheet
11:20  Building a public Carrd.co form to post workouts
12:43  Testing the Carrd form into the sheet
13:16  Conclusion and course references

Watch: https://www.youtube.com/watch?v=Lf2f1HxzQI0