Tools and editors

There are plenty of tools for woking with reStructuredText. Also, almost any code editor has reStructuredText files support ranging from simple syntax highlighting to auto-complete, preview, showing errors, linting, etc.

For exahusive list see e.g., https://stackoverflow.com/questions/2746692/restructuredtext-tool-support.

Online preview

The Snippets (https://snippets.documatt.com) is online reStructuredText editor can be used to play with the markup and see the results immediately.