You can use subdomains and even sub-subdomains as your custom link domain in Bitly.
Keep these things in mind as you choose and set up a custom domain:
- The domain for your short links must be different than your website domain.
- It can't be more than 32 characters long, including the dot.
- If you haven't added one yet, Bitly offers a complimentary domain. However, if you add your own domain, you won't be able to redeem this offer later.
When using a subdomain configured with DNS A Records, you will need to update the A Records to point to 188.8.131.52 and 184.108.40.206. If you are using a subdomain configured with a CNAME in your DNS record, you will not need to update anything.
You can check if your subdomain is configured correctly by visiting your Bitly Advanced Settings.