Publishing a podcast: formats, specs and platforms

How publishing a podcast works, in brief

You do not upload your audio to the platforms. You host it online, the host generates an RSS feed (a web address describing the show and listing the episodes), and you submit that feed once to Apple Podcasts and Spotify. They then fetch each new episode from the feed automatically. Submitting is free; only hosting may cost money.

The RSS feed, explained simply

The RSS feed is an XML file your host maintains. It carries the show-level information (title, description, language, category, cover art, explicit flag) and one entry per episode. Each episode entry includes an enclosure, which is the actual link to the audio file, plus a unique identifier the platforms use to track it.

• Channel level: title, description, language (a valid code like en or fr), itunes:explicit, an iTunes category, and the cover image.
• Episode level: an enclosure with three required attributes (url, length in bytes, type such as audio/mpeg), a title, and a GUID.
• The GUID must be unique and never change, even if you edit the title or move the file.

Audio format and bitrate

The feed serves MP3 or AAC. For an MP3, Apple recommends mono at 96 to 128 kbps or stereo at 128 to 256 kbps, at 44.1 or 48 kHz (64 kbps is a generic low-bitrate option, not Apple's recommendation). For a spoken-word show, mono at 96 to 128 kbps is plenty and keeps files small. Use constant bitrate (CBR) for reliable playback and seeking.

• RSS feed: MP3 or AAC. Mono 96 to 128 kbps, stereo 128 to 256 kbps, 44.1 or 48 kHz (64 kbps is a generic minimum, not Apple's recommendation).
• Constant bitrate (CBR), not variable, for dependable seeking across apps.
• Master in WAV or FLAC and export the MP3 once. Re-encoding an existing MP3 stacks compression artefacts.
• Set loudness before export: target around -16 LUFS for stereo (-19 LUFS for mono) with a true peak of -1 dBTP, the common podcast loudness convention.

Cover art: specs and mistakes to avoid

Cover art must be square. Apple and Spotify accept 1400 x 1400 px minimum up to 3000 x 3000 px, at 72 DPI, as JPEG or PNG, in RGB, with no transparency. Apple does not publish a file-size cap, but keep the file lightweight so it loads quickly. Keep text, faces and logos out of the bottom 15 percent, where the playback bar sits.

• Square, 1400 to 3000 px, 72 DPI, JPEG or PNG, RGB, no alpha channel.
• Keep the cover file lightweight for fast loading; Apple sets no fixed file-size limit.
• The cover embedded in the MP3 ID3 tag should be small, around 600 x 600 px and under 200 KB.
• Avoid important elements in the bottom 15 percent (the progress bar).

Submitting to Apple Podcasts

In Apple Podcasts Connect, choose Add a show, then add a show with an RSS feed, and paste your feed URL. Apple emails the address listed in the feed to verify ownership, then runs a technical and editorial review. Review times vary and Apple does not publish a fixed timeline.

Submitting to Spotify

In Spotify for Creators, choose Add show, select that you already have a podcast, and paste your RSS feed URL. Spotify sends a verification code to the feed's email address, then publishes the show, often within hours. You submit the feed once; new episodes appear automatically afterward.

How long, and is it free

Submitting a podcast to the platforms is free. What can cost money is hosting, the service that stores your files and generates the feed. After the one-time submission, every new episode flows through the feed automatically, so you never resubmit. Spotify often validates within hours; Apple's review time varies and Apple does not publish a fixed timeline.

Anti-rejection checklist

Most rejections are a spec miss. Confirm these before you submit.

• Cover art square, 1400 to 3000 px, RGB, no transparency.
• Feed declares a valid language code, an explicit flag, and an iTunes category.
• Each episode enclosure has url, length and type, and a unique unchanging GUID.
• Audio is CBR MP3 at the right bitrate, 44.1 kHz, around -16 LUFS stereo (-19 LUFS for a mono spoken-word show) / -1 dBTP.
• The feed's owner email is one you can access (Apple and Spotify verify it).

Choosing a host

You need a host before you can submit anywhere: the host stores your audio and generates the RSS feed that every platform reads. Pick it on a few neutral criteria rather than on brand. The differences that matter for an engineer are storage, monthly bandwidth, how the host auto-distributes to directories, and the depth of its analytics.

Hosts split into free and paid tiers. Free tiers usually trade away storage, bandwidth or analytics, and some inject their own ads. Whatever you choose, the host must let you keep ownership of the RSS feed and export it, so you can move without losing your subscribers.

• Storage: total hours of audio you can keep online, which caps how long a back catalogue you can host.
• Bandwidth: monthly download allowance; a show that grows can hit a free tier's ceiling.
• Auto-distribution: whether the host submits your feed to Apple Podcasts, Spotify, YouTube and Amazon Music for you, or you paste the feed yourself.
• Analytics: IAB-style download and listener metrics, and how far back the history goes.
• Free vs paid: free tiers often cap storage or bandwidth and may add ads; confirm you keep and can export the RSS feed either way.
• Common neutral options include Acast, Ausha, Buzzsprout, Castos, Podbean, RSS.com and Transistor; compare them on the criteria above, not on name.

Apple Podcasts vs Spotify: the specs side by side

The two main platforms read the same RSS feed but state their own limits. The figures below come from Apple Podcasts for Creators and Spotify for Creators. Meet the stricter of the two on each spec and the same file satisfies both platforms' file requirements (acceptance also depends on a valid feed and editorial review).

Where your feed goes in 2026

Apple Podcasts and Spotify are no longer the only destinations worth submitting to. Both YouTube and Amazon Music now take your existing RSS feed. On YouTube, the feed is connected once and episodes appear in the YouTube Music app; on Amazon Music, you submit the same feed and the show also reaches Audible and Alexa devices. As with Apple and Spotify, you submit the feed once and new episodes follow automatically.

• YouTube Music: connect the RSS feed and episodes are generated automatically from your audio and show art.
• Amazon Music: submit the same RSS feed; the show also surfaces on Audible and Alexa-enabled devices.
• Deezer: submit the same RSS feed once, or let your host distribute it.
• Most other directories (Ausha, Acast, Castbox, Podchaser) read the same feed, and many are reached automatically through your host, so you submit once and they follow.