> For the complete documentation index, see [llms.txt](https://docs.feedotter.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.feedotter.com/newsletters/advanced.md).

# Advanced

- [Custom API Embed](https://docs.feedotter.com/newsletters/advanced/custom-api-embed.md): Useful for pulling ad or external content into your newsletter apart from using content sources.