Go to page 2 and find an API of your liking. Then begin coding a complete web-app to suit your needs.
Below this text, you can see an example of how to pull API data into your app. The page basically uses three techonologies to make this happen:
Click the button to get suggestions for public API's with no authentication.
Follow the link to see the API documentation. Remark: every API has one or more "endpoints" - this is basically a root url to access the API. Then most API's have additional "query values", which is used to specify further parameters.
For example: