[SOLVED] Why did I suddenly get "You've exceeded the Rate Limit" error?

Why did I suddenly get "You've exceeded the Rate Limit" error?

Problem:

On July 23, this code suddenly stop working.

Environment:

I am running this code on Google Apps Script.
I call only 14 calls per day for the coin gecko API server.
8 calls / sec. is the Coin Gecko's rate Limit.
50 calls / min. is its Free Plan's Rate Limit.
I am using Coin Gecko Free Plan.
I do use Utilities.sleep() accordingly.
There are no problems with the browser. https://api.coingecko.com/api/v3/coins/bitcoin/
The busy-server-error-message used to be a different message. But now it returns a different error message.

Error Message:

Exception: Request failed for https://api.coingecko.com returned code 429. Truncated server response: {"status":{"error_code":429, "error_message": "You've exceeded the Rate Limit. Please visit https://www.coingecko.com/en/api/pricing to subscribe to ... (use the muteHttpExceptions option to examine the full response)

Code:

function test() {
  const URL = 'https://api.coingecko.com/api/v3/coins/bitcoin'
  
  Utilities.sleep(10000)
  const fetchedData1 = UrlFetchApp.fetch(url)
  console.log(fetchedData1)

  Utilities.sleep(10000)
  const fetchedData2 = UrlFetchApp.fetch(url)
  console.log(fetchedData2)
  
}

Solution

Try adding Utilities.sleep(10000); before CoinGecko.tryCatch(i); to reduce the calls rate to the API.

Use trial and error to find the "optimal value" for the Utilities.sleep parameter and use together with an advanced algorithm like exponential backoff to handle Google Apps Script performance variations.