Https://codefile.io/ is free and you can set the Snippet formatting to be Swift. Source: about 1 year ago

Carbon is a free online code screenshot tool that helps users create beautiful code screenshots for use in blogs, social media, or presentations. It provides a simple interface that allows users to enter their own code and choose different themes, fonts, and color schemes. Users can also adjust the code alignment, line numbers, background, shadow, etc. To better control the screenshot effect. Carbon also supports... - Source: dev.to / about 1 month ago

Carbon, an online code beautification tool, lets you create visually appealing code screenshots with a simple interface, enhancing code readability. - Source: dev.to / 3 months ago

Carbon.now.sh - create and share code snippets in an aesthetic screenshot-like image format. Usually used to aesthetically share/show off code snippets on Twitter or blog posts. - Source: dev.to / 4 months ago

You could try Carbon: https://carbon.now.sh/. - Source: Hacker News / 7 months ago

Carbon allows you to create stunning and customizable code screenshots with syntax highlighting. Whether you want to share code snippets on social media or enhance your documentation, Carbon is a handy tool to have in your arsenal. - Source: dev.to / 8 months ago