This web tool lets you upload one or more CSV files and turn them into a browseable web user interface and JSON API using Datasette.
Important note: Data deployed using this tool should not be expected to stay online permanently, as Zeit have announced their intention to deprecate the underlying hosting mechanism at some point in the future. They have promised to provide six months notice of this.
Here are some examples of the kind of thing you can build with Datasette:
For more on this project, see Datasette Publish: a web app for publishing CSV files as an online database