Short.io lets you create short links in bulk in two ways.
a) Use the Short.io API.
With Short.io API, you can shorten up to 1000 links in one API call. You can create 5 requests per 10 seconds (1 request = 1000 URLs).
It works almost the same as a single link creation endpoint, but it accepts an array of URLs and returns an array of responses back. If any URL fails to be added, it turns an error object back as an array element. The method is not transactional. It can insert some links from the list and return an error for others.
b) Import CSV.
You can import CSV with links you want to shorten, or an export file from another link shorteners like Bitly or YoURLs
c) Use the Google spreadsheet.
Using a Google Spreadsheet doesn't require technical skills. When applying this method you paste links manually.
The detailed instruction below helps you to configure bulk link creation
1. Log in to Short.io account.
2. Go to your short URL list.
3. Click "Bulk Create."
4. Fill the fields.
5. Click Create links.
6. Links are shortened.
Now all your newly created short links are on the dashboard.