The reason Twitter deprecated the Twitter 1.1 API, which broke everyone’s code, is to push users to their native embed Twitter timeline widget, which happens to force users to use oAuth to display their publicly available tweets. In my opinion, for Twitter to all of a sudden just stop supporting Twitter 1.1 API is a pretty crappy way to treat their developer community.
You can find the code here: http://www.jasonmayes.com/projects/twitterApi
In order to get his code to work on your Tumblr, here is what you need to do.
Step 1: Log into Twitter and create your own timeline widget. This part is key in order to get your ID number. After creating the widget, in the Twitter URL will be the ID number you will need to display your tweets. It will look similar to this URL for my widget (in bold is the ID): twitter.com/settings/widgets/347077469637079040/edit
Step 3: Open up Notepad or a text editor, and paste the code into it. Then make sure to replace the ID number with your ID number. The line of code will look like this: twitterFetcher.fetch(‘347077469637079040’, ‘tweets2’, 5, true, false, true, dateFormatter, false);
Step 4: After making the edit, save the file. Then either you can host it externally yourself if you have your own domain (like I did here) or for those without your own domain, Tumblr allows you to upload static files to the site to be hosted. You can load the saved file here on Tumblr: http://www.tumblr.com/themes/upload_static_file
Step 5: Once the file is loaded, simply go back to Jason’s Twitter API page, copy the HTML, add it to your site where you want the tweets to appear, then add your script file directly under the HTML. It will look similar to this:
That’s it, you’re done. For most devs, Jason’s code as-is will work fine. The trouble I encountered was with how Tumblr handled his script, which is why you may want to follow the steps above to get tweets displayed on Tumblr without having to use their embed widget. If you run into any trouble or have questions on this, please feel free to leave a comment below.