Tumult Whisk’s integrated live preview breaks the tedious cycle of writing HTML, saving the file, then reloading and viewing the page in the browser. Combining the writing phase with the viewing phase clarifies the effects of your changes and speeds up the overall process of making a web page. W3C-based validation will red-underline any mistakes. It uses the same rendering engine found in Safari, so it is not only standards compliant, but also very fast.
Preview pane quickly renders HTML and PHP as typed, using the same engine as Safari
Watched Files automatically (or manually) determine when files are changed and will reload the web preview.
Live HTML W3C-based validation shows errors and highlights problem tags with a red underline
Preview to other browsers or the Hype Reflect app on iOS.
Web inspector/console/dev tools access.
Customizable syntax highlighting coloring.
Reusable code snippets and color swatches.
Scroll sync keeps can keep the editor and preview at similar spots.
View HTML source code generated by the PHP engine.
Attach Style Sheets for viewing how blog posts/markup will look with external styling.
Written in Cocoa exclusively as a macOS app (supports 10.11 through 10.15).
Adopts new macOS features and is gorgeous in Light and Dark modes