The t.co link will always be substituted in the tweet text returned by the API. This is done partially to help prevent the spread of potentially abusive links (e.g., links to point to malware). However, you can always get the original link back by looking at the “entities” key in the tweet’s JSON response.
If the tweet contains any links, then the entities key will contain a “urls” key, which will have the following information:
- url: The t.co link
- expanded_url: The original url. In your case, this will be the bit.ly link
- display_url: A display version of the expanded_url
- indices: Indices of the tweet text where the display_url should be substituted for the t.co link