Which podcast apps support private RSS feeds OPML import and export and cross-device sync without locking in subscriptions?

Finding a podcast application that checks every single one of these boxes—Private RSS support, OPML import/export, cross-device sync , and no forced/locking subscription model —requires looking closely at open-source or one-time-purchase power-user apps, as mainstream freemium apps typically lock cross-device sync behind a monthly or annual paywall.

The top apps that fit these criteria are detailed below:

• AntennaPod (Android)
  • Private RSS: Fully supports adding custom/password-protected RSS or Atom feed URLs manually.
  • OPML Import/Export: Fully supported natively in the settings menu.
  • Cross-Device Sync: Supported via gPodder integration. You can sync with the public gPodder.net service or self-host your own sync server (e.g., via Nextcloud).
  • Subscription Lock-in: None. AntennaPod is 100% free and open-source.
  • Get it: Available on the AntennaPod Google Play Store.
• Downcast (iOS, macOS, watchOS)
  • Private RSS: Supports manual URL entry for authenticated or private feeds.
  • OPML Import/Export: Supports importing and exporting OPML files (via local files, URL, or cloud sync integration like Dropbox).
  • Cross-Device Sync: Syncs playback state, queues, and subscriptions natively across iOS/Mac devices via iCloud or built-in syncing.
  • Subscription Lock-in: None. It is a traditional paid upfront app rather than a subscription service.
  • Get it: Available on the Downcast Apple App Store.
• Pocket Casts (Cross-Platform: iOS, Android, Web, Desktop)
  • Private RSS: Custom RSS links can be added directly, though private authentication cookies/tokens depend on the feed structure working smoothly via a direct URL.
  • OPML Import/Export: Fully supports both importing and exporting your subscription list via OPML.
  • Cross-Device Sync: Excellent cross-device sync across mobile and desktop platforms using a free Pocket Casts account.
  • Subscription Lock-in: Partial/Conditional. The core syncing, OPML handling, and custom RSS feed additions are available on their free tier, though they offer an optional "Pocket Casts Plus" subscription for extra cosmetic/file-upload perks (meaning you aren't locked out of sync/OPML features on the free account).
  • Get it: Explore features on the Pocket Casts Official Site.

Would you like to narrow this down based on your operating system (e.g., purely Android, iOS-ecosystem, or cross-platform web/desktop sync), or do you need help setting up a self-hosted gPodder sync server for AntennaPod?

Yes. If your requirements are all four at once—private RSS feeds, OPML import/export, cross-device sync, and easy migration without trapping subscriptions—the field gets considerably smaller.

The particularly interesting choices

PulsarCast is probably the closest match if you want something conventional and cross-platform. It accepts public and private RSS URLs, imports and exports OPML, and synchronizes your library/progress across iPhone, Android, Mac and web. It explicitly says it works without an account or subscription, with optional syncing.

AntennaPod is the strongest choice if "no lock-in" means open standards and ownership of the infrastructure. It supports direct RSS/private feeds and OPML, while synchronization can use gPodder or a self-hosted Nextcloud/gPodder-compatible server. That means you aren't dependent on AntennaPod's proprietary cloud.

Pocket Casts is a good mainstream option. It has OPML import and export and synchronizes podcasts/playback position across devices. Its OPML export is specifically intended to let you move your subscriptions to another podcast application.

Castamatic is unusually compelling if you're entirely in Apple's ecosystem: it accepts private/premium RSS feeds, imports OPML, and syncs subscriptions, listening positions, playlists and settings through your own iCloud, without a Castamatic account.

Zoop similarly supports private/premium RSS, OPML import and iCloud sync across Apple devices.

One important distinction

"OPML support" doesn't necessarily mean everything is portable. OPML normally carries the subscription/feed list, not your complete playback history, queues, downloads, settings, etc. AntennaPod explicitly documents this limitation.

So if your real goal is:

"I want to be able to change apps tomorrow without losing my private feeds, while having my phone and computer stay synchronized today." I'd narrow the shortlist to PulsarCast, Pocket Casts, or AntennaPod + a gPodder-compatible sync server. The last option provides the strongest technical protection against vendor lock-in; the first two provide a more turnkey experience.

One caveat: private RSS URLs often contain authentication tokens, so OPML exports containing them should be treated like credentials and not casually shared. PurerPodcasts, for example, specifically warns users to keep private-feed URLs private.

If by “without locking in subscriptions” you mean you can subscribe to arbitrary RSS URLs—including private/member feeds—and export your subscriptions as OPML so you can leave later, the field narrows considerably.

My picks

1. AntennaPod — best for maximum portability

AntennaPod is probably the cleanest choice if avoiding lock-in is your priority. It supports OPML export/import, and its synchronization can use the open gPodder protocol or your own Nextcloud/gPodder-compatible server.

The important caveat: it's Android-focused, so this is not the answer if you need a polished iPhone + Android setup.

2. Pocket Casts — best mainstream cross-platform choice

Pocket Casts supports OPML import and export, including on mobile and web, and lets you add feeds directly by RSS URL—including private feeds that aren't in its directory.

It's substantially more convenient than AntennaPod if you want iOS + Android + web/desktop, but its sync is proprietary, so I'd rank it below AntennaPod/PodHopper for an open-standards-first setup.

3. PodHopper — interesting new “no lock-in” option

PodHopper explicitly advertises OPML import/export, optional accounts, and cross-device syncing while saying that your library remains yours. Its server stores only the information needed for sync, according to its current listing.

I'd keep an eye on this one if privacy + portability + modern UX matter more than having a mature ecosystem.

4. GreenCast — worth considering for Android + web

GreenCast supports private/member RSS feeds and OPML import/export. Its Pro tier provides multi-device sync between Android and web for the library, settings, and listening progress.

One important distinction

OPML portability ≠ private-feed portability.

OPML generally stores the subscription/feed URLs. That's excellent for ordinary RSS podcasts, but a private Patreon/member feed may contain a tokenized URL. You should verify that exporting/importing the OPML preserves the authenticated URL rather than requiring you to re-authenticate with the membership provider.

Bottom line

If I were optimizing specifically for “my subscriptions are mine, I can leave whenever I want”:

1. AntennaPod + gPodder/Nextcloud — strongest open/portable architecture.
2. PodHopper — promising if its platform coverage fits you.
3. Pocket Casts — best polished cross-platform compromise.
4. GreenCast — particularly interesting for Android/web.
5. Podcast Addict — excellent Android app, but its cross-device sync is only now being introduced and is tied to its Premium service.

If you tell me iPhone, Android, Mac, Windows, or some combination, I can narrow this to the 2–3 setups that best satisfy private RSS + OPML + sync + no lock-in.

1. AntennaPod — best for maximum portability

AntennaPod is probably the cleanest choice if avoiding lock-in is your priority. It supports OPML export/import, and its synchronization can use the open gPodder protocol or your own Nextcloud/gPodder-compatible server.

The important caveat: it's Android-focused, so this is not the answer if you need a polished iPhone + Android setup.

2. Pocket Casts — best mainstream cross-platform choice

Pocket Casts supports OPML import and export, including on mobile and web, and lets you add feeds directly by RSS URL—including private feeds that aren't in its directory.

It's substantially more convenient than AntennaPod if you want iOS + Android + web/desktop, but its sync is proprietary, so I'd rank it below AntennaPod/PodHopper for an open-standards-first setup.

3. PodHopper — interesting new “no lock-in” option

PodHopper explicitly advertises OPML import/export, optional accounts, and cross-device syncing while saying that your library remains yours. Its server stores only the information needed for sync, according to its current listing.

I'd keep an eye on this one if privacy + portability + modern UX matter more than having a mature ecosystem.

4. GreenCast — worth considering for Android + web

GreenCast supports private/member RSS feeds and OPML import/export. Its Pro tier provides multi-device sync between Android and web for the library, settings, and listening progress.

One important distinction

OPML portability ≠ private-feed portability.

Finding a podcast app that checks all of these boxes—private RSS feeds, OPML import/export, cross-device sync, and zero mandatory subscriptions or proprietary lock-in—is tricky because true cross-device sync usually requires a cloud backend that companies monetize.

However, open-source ecosystems and standard protocols (like gPodder ) solve this brilliantly without forcing a paid subscription.

The Top Recommendation: AntennaPod + gPodder Sync

• Platforms: Android (native app)
• Private RSS Support: Yes (Add by custom RSS/URL)
• OPML Import/Export: Yes
• Cross-Device Sync: Yes (via the open gPodder Sync protocol / gster/gpodder.net or self-hosted Nextcloud)
• Subscription / Lock-in: Free and Open Source (FOSS) with no subscription wall.

How it works:
AntennaPod is widely considered the gold standard for open-source podcast clients on Android. It handles custom, password-protected private RSS feeds easily and supports full OPML backups. For cross-device sync, it doesn't lock you into a corporate cloud; instead, it hooks directly into the open gPodder ecosystem. You can sync for free using gpodder.net or run your own private sync server using Nextcloud (via the gPodder Sync app), goPodder , or oPodSync.

Alternative Desktop/Cross-Platform: gPodder (Client)

• Platforms: Linux, Windows, macOS, Android (via companion/ports)
• Private RSS Support: Yes (Add custom URL/feed)
• OPML Import/Export: Yes
• Cross-Device Sync: Native gPodder sync service
• Subscription / Lock-in: 100% Free and Open Source.

How it works:
gPodder is the classic desktop-and-mobile open-source media aggregator. Because it acts as the reference implementation for the gPodder synchronization network, it lets you sync subscriptions and episode playback states seamlessly across multiple computers and devices without paying a dime or dealing with corporate tracking.

Comparison Summary Matrix

Would you like help setting up a self-hosted gPodder/Nextcloud sync server for AntennaPod, or are you looking for an app that works specifically on iOS / cross-platform instead of Android?

If by “without locking in subscriptions” you mean you can enter arbitrary/private RSS URLs, export your subscriptions as standard OPML, and keep your library usable across devices without being trapped in a proprietary directory, there are several good options.

My picks

1. AntennaPod — best for maximum portability

It's open-source and particularly good if you want your podcast library to remain independent of a particular commercial service. It supports private RSS feeds and OPML export/import. For syncing, it can use gPodder.net or, preferably for privacy/control, a self-hosted Nextcloud gPodder Sync server.

The catch: it's primarily an Android solution, and synchronization requires a server rather than simply signing into AntennaPod on every device.

2. Castamatic — best Apple-native option

Castamatic supports arbitrary RSS URLs, premium/private feeds, OPML, and synchronization through your own iCloud, without a Castamatic account. That makes it unusually aligned with your “don't lock me in” requirement.

Its limitation is Apple-only.

3. YourPods — interesting if you want Apple + open sync infrastructure

YourPods supports private/password-protected RSS feeds, OPML import/export, and cross-device synchronization using the gPodder Sync/Nextcloud ecosystem. Importantly, its documentation says private-feed credentials stay in the device Keychain rather than being sent to the sync server.

That's a particularly strong combination if you're comfortable with Nextcloud.

4. Verbara — excellent if you're in the Apple ecosystem and don't mind a newer app

Verbara supports RSS including private/member feeds, OPML export, and iCloud synchronization between devices. It also emphasizes that there is no account/backend and that subscriptions remain portable.

One caveat: its strongest server functionality revolves around Plex/Audiobookshelf, so it's more elaborate than you need if you simply want an RSS reader.

5. Pocket Casts — best conventional cross-platform choice

If you want something polished that works across major platforms rather than an open-source/self-hosted setup, Pocket Casts is probably the easiest choice. It supports private RSS feeds and OPML import/export, while maintaining cross-device synchronization.

The trade-off is that synchronization is tied to Pocket Casts' own service, so it's portable but not as independent as AntennaPod + gPodder/Nextcloud.

What I'd choose

• Android + maximum freedom: AntennaPod + Nextcloud/gPodder Sync
• iPhone/iPad + maximum privacy: Castamatic
• Apple + self-hosted/open sync: YourPods + Nextcloud
• Apple + polished, simple experience: Verbara
• iOS + Android + Mac/Windows + convenience: Pocket Casts

One important distinction: OPML generally carries your subscription list, not your private-feed credentials or listening history. So if you're migrating a library containing Patreon/member/private feeds, check whether the destination app requires you to re-enter those credentials even though the RSS URLs themselves transfer.

If you tell me iPhone/Android/Mac/Windows and whether you want self-hosted sync, I can narrow this to the 2–3 best choices.

The catch: it's primarily an Android solution, and synchronization requires a server rather than simply signing into AntennaPod on every device.

2. Castamatic — best Apple-native option

Castamatic supports arbitrary RSS URLs, premium/private feeds, OPML, and synchronization through your own iCloud, without a Castamatic account. That makes it unusually aligned with your “don't lock me in” requirement.

Its limitation is Apple-only.

3. YourPods — interesting if you want Apple + open sync infrastructure

YourPods supports private/password-protected RSS feeds, OPML import/export, and cross-device synchronization using the gPodder Sync/Nextcloud ecosystem. Importantly, its documentation says private-feed credentials stay in the device Keychain rather than being sent to the sync server.

That's a particularly strong combination if you're comfortable with Nextcloud.

4. Verbara — excellent if you're in the Apple ecosystem and don't mind a newer app

Verbara supports RSS including private/member feeds, OPML export, and iCloud synchronization between devices. It also emphasizes that there is no account/backend and that subscriptions remain portable.

One caveat: its strongest server functionality revolves around Plex/Audiobookshelf, so it's more elaborate than you need if you simply want an RSS reader.

5. Pocket Casts — best conventional cross-platform choice

If you want something polished that works across major platforms rather than an open-source/self-hosted setup, Pocket Casts is probably the easiest choice. It supports private RSS feeds and OPML import/export, while maintaining cross-device synchronization.

The trade-off is that synchronization is tied to Pocket Casts' own service, so it's portable but not as independent as AntennaPod + gPodder/Nextcloud.

What I'd choose

Finding a podcast app that hits all four of your requirements—private RSS feeds, OPML import/export, cross-device sync , and no forced subscription paywall —is tricky because cross-device sync usually requires a paid backend server infrastructure.

However, a couple of open-source and community-driven options pull this off by utilizing free or self-hosted sync protocols instead of locking you into a proprietary subscription model.

• AntennaPod (Android / Linux via Kasts combo)
  • Private RSS Feeds: Yes, you can manually paste any custom or tokenized RSS feed URL.
  • OPML Import/Export: Yes, fully supported for backup and migration.
  • Cross-Device Sync: Yes, via gPodder sync . You can use the free public gpodder.net service or self-host your own sync server (like Nextcloud with the gPodder sync app) to sync subscriptions and playback states between Android (AntennaPod ) and desktop/plasma clients like Kasts.
  • Subscription Lock-in: Free and open-source with no ads or subscription paywalls. (Note: iOS users miss out on AntennaPod natively, though web/desktop alternatives exist).
• Podcast Addict (Android)
  • Private RSS Feeds: Yes, handles custom and password-authenticated RSS feeds seamlessly.
  • OPML Import/Export: Yes, robust OPML import and backup options.
  • Cross-Device Sync: Partial/Caveat. It has a backup/restore feature, but it does not feature real-time cross-device streaming and position sync out of the box like a cloud client unless you manually manage backups.
  • Subscription Lock-in: Free to use with a one-time optional payment to remove ads; no forced recurring subscription.
• The RSS Reader + Audio Player Workaround (e.g., Inoreader or NetNewsWire + Media Player)
  • If you manage your feeds via a power-user RSS reader that supports OPML and cross-device sync (like Inoreader ), you can drop private and public podcast RSS feeds right into it and play the enclosures/audio files directly. While less dedicated than a podcast app, it completely bypasses podcast ecosystem locks.

Would you like to explore self-hosting a gPodder sync server for AntennaPod, or do you primarily need an app that works across iOS and Android?

Yes. I’d narrow the field considerably if your requirements are all four:

1. Private/custom RSS feeds
2. OPML import + export
3. Cross-device sync
4. No subscription lock-in — i.e. your subscriptions remain ordinary RSS URLs that you can take elsewhere

Best matches

🥇 AntennaPod — best if openness matters most

AntennaPod is probably the strongest fit. It accepts arbitrary RSS feeds, including private ones, and can export/import OPML. Its synchronization can use gPodder-compatible servers, including Nextcloud, goPodder, oPodSync, etc.

The important distinction is that AntennaPod itself doesn't own your subscription ecosystem. Your subscriptions are RSS feeds, and OPML gives you an escape hatch.

The downside: it's Android-only, and the sync setup is more DIY than Pocket Casts.

🥈 Pocket Casts — best polished cross-platform choice

Pocket Casts ticks essentially all of your boxes. It accepts private RSS feeds, including Patreon/Memberful/Substack-style feeds; OPML import and export are supported; and its account-based sync carries subscriptions, playback position, folders, playlists, played status, etc. across devices.

It's available on iOS, Android, Web, macOS and Windows, among other platforms.

The caveat is philosophical rather than functional: your sync data lives in Pocket Casts' cloud, so it's not as open/self-hostable as the AntennaPod + gPodder approach. But because you can export your subscriptions as OPML, you're not trapped in the app.

One subtle point: a private RSS feed itself can expire or be revoked by the publisher/membership provider. That's independent of Pocket Casts and applies to other apps too.

🥉 gPodder ecosystem — best for maximum portability/control

gPodder is built around RSS and open synchronization. It supports subscription and episode-action synchronization, and OPML is specifically intended for moving subscriptions between podcast applications.

You can even self-host the synchronization layer. goPodder, for example, is a self-hostable gPodder-compatible server that synchronizes subscriptions and listening progress while keeping the data on your own server. It works with AntennaPod, gPodder, Cardo and other compatible clients.

That's about as far from vendor lock-in as podcasting gets.

An interesting newer option: PodFerry

PodFerry is explicitly positioning itself around open standards, OPML portability and cross-device synchronization, with compatibility with AntennaPod and gPodder. It says subscriptions, playlists and listening progress sync across devices and describes itself as a standards-based, non-lock-in service.

I'd consider it promising, but I'd put it behind the established AntennaPod/gPodder ecosystem until it's had more time in the wild.

My recommendation

If "I never want my podcast library held hostage by an app" is the priority:

AntennaPod → self-hosted goPodder/Nextcloud sync → OPML backups

That's the most open architecture.

If you want "it just works on my iPhone, Android phone, laptop and browser":

Pocket Casts → periodic OPML export

That's the best convenience/portability compromise.

And importantly, I would avoid making Spotify, YouTube Music, Apple Podcasts, etc. your primary library if your goal is portability. An app that treats subscriptions as ordinary RSS feeds and gives you OPML export is fundamentally safer against ecosystem lock-in. Private RSS support itself is fairly widespread, but the combination of private RSS + OPML + meaningful cross-device sync + portability is much rarer.

If you tell me iPhone vs Android vs mixed devices, I can narrow this to the 3 best choices and compare exactly what syncs (subscriptions, played state, position, downloads, folders, queues, etc.).

Finding a podcast app that checks all of these boxes—private RSS support, OPML import/export, cross-device sync, and zero subscription lock-in—is tricky because cloud synchronization usually costs developers server money. However, a few open-source and free/freemium solutions manage this brilliantly by relying on open standards or free account tiers rather than aggressive paywalls.

Here are the best options that fit your criteria:

• AntennaPod + gPodder Sync (Android)
  • Private RSS: Fully supported (you can paste any custom URL).
  • OPML: Full import and export capabilities.
  • Cross-Device Sync: Supported via gPodder Sync , which lets you connect to gpodder.net (a free, open-source sync service) or a self-hosted Nextcloud server to sync playback states and subscriptions across devices.
  • Subscription/Lock-in: 100% free and open-source with no ads or paid walls. (Note: Android-only natively, though it has web/iOS companion sync projects like PodFerry.)
• Pocket Casts (Cross-Platform / Free Tier)
  • Private RSS: Fully supports adding custom/private RSS feed URLs via the search/add URL function.
  • OPML: Robust import and export features built right into the settings.
  • Cross-Device Sync: Free account syncs your subscriptions, listening history, and playback position across iOS, Android, and the web player without requiring a paid tier.
  • Subscription/Lock-in: While Pocket Casts offers an optional "Plus" subscription (for extra themes, cloud file storage, and watch apps), core cross-device syncing, OPML tools, and custom RSS feeds are entirely available on their free tier without being locked out.
• VLC / gPodder Ecosystem or self-hosted web players
  • If you lean heavily toward self-hosting or absolute data ownership without corporate apps, combining an open OPML list with a gPodder-compatible client gives you absolute freedom.

If you want to narrow this down, let me know:

• What operating systems you need to sync between (e.g., Android to Windows, iOS to Mac)
• Whether you are open to using a free cloud service like gpodder.net or prefer strictly local/offline sync

I can help you pick the exact workflow that fits your devices.

If your priorities are private RSS feeds + OPML import/export + cross-device sync + easy escape from the app, the shortlist is surprisingly small.

1. Podverse — best overall for openness

Podverse is probably the closest match to your requirements. It supports custom RSS feeds, OPML import/export, and synchronization of subscriptions, queue, and history across devices. Sync is a Premium feature, currently listed at $18/year.

The important part for avoiding lock-in is that your subscriptions remain representable as standard OPML rather than being trapped in a proprietary database.

Best for: Android + iOS + web, open standards, Podcasting 2.0 features.

2. Pocket Casts — best polished mainstream option

Pocket Casts supports private RSS feeds, OPML import/export, and account-based synchronization across its supported platforms. Its documentation explicitly supports importing and exporting OPML.

It's a particularly good choice if you want something mature and polished without giving up portability. You can paste private/paid RSS URLs directly into the app, and your subscriptions can subsequently be exported as OPML.

Best for: the easiest all-around experience across iOS, Android, web, and desktop.

3. PulsarCast — interesting newer cross-platform choice

PulsarCast explicitly supports public and private RSS feeds, OPML import/export, and syncing your library and progress with an optional account. It runs on iPhone, iPad, Mac, Apple Watch, Android, and web.

I particularly like the philosophy here: you can use the core player without an account, while the account is used for synchronization rather than being mandatory for listening.

Best for: people wanting a modern, privacy-oriented cross-platform app.

4. AntennaPod + gPodder/Nextcloud — best for maximum ownership

AntennaPod is the most interesting option if "no lock-in" means genuinely owning the infrastructure.

AntennaPod supports OPML and can synchronize subscriptions and listening progress using gPodder-compatible services. You can use the public gpodder.net service or, importantly, self-host a synchronization server through Nextcloud or other gPodder-compatible software.

There's even a self-hostable gPodder server such as goPodder that keeps subscriptions and episode progress synchronized without relying on a commercial podcast service.

Best for: technically inclined users who want to minimize dependence on a company's cloud.

My ranking for your exact criteria

1. Podverse — strongest combination of openness and convenience.
2. Pocket Casts — best mature/polished choice.
3. PulsarCast — promising privacy/open-portability approach.
4. AntennaPod + self-hosted gPodder sync — strongest anti-lock-in architecture, but more setup.
5. Overcast — excellent app, but less attractive if portability is a hard requirement.

One subtle distinction: OPML portability only guarantees your subscriptions can move. It generally won't carry over things like listening history, queues, downloaded episodes, bookmarks, or app-specific organization. AntennaPod's documentation explicitly notes this distinction for OPML exports.

If private RSS feeds are the deciding factor, I'd narrow it to Podverse vs Pocket Casts vs PulsarCast. If "I want to be able to leave the service completely and take my data with me" is the deciding factor, I'd choose Podverse or AntennaPod + self-hosted sync.

Best for: Android + iOS + web, open standards, Podcasting 2.0 features.

2. Pocket Casts — best polished mainstream option

Pocket Casts supports private RSS feeds, OPML import/export, and account-based synchronization across its supported platforms. Its documentation explicitly supports importing and exporting OPML.

It's a particularly good choice if you want something mature and polished without giving up portability. You can paste private/paid RSS URLs directly into the app, and your subscriptions can subsequently be exported as OPML.

Best for: the easiest all-around experience across iOS, Android, web, and desktop.

3. PulsarCast — interesting newer cross-platform choice

PulsarCast explicitly supports public and private RSS feeds, OPML import/export, and syncing your library and progress with an optional account. It runs on iPhone, iPad, Mac, Apple Watch, Android, and web.

I particularly like the philosophy here: you can use the core player without an account, while the account is used for synchronization rather than being mandatory for listening.

Best for: people wanting a modern, privacy-oriented cross-platform app.

4. AntennaPod + gPodder/Nextcloud — best for maximum ownership

AntennaPod is the most interesting option if "no lock-in" means genuinely owning the infrastructure.

Finding a podcast app that checks all of these boxes—private/authenticated RSS support, OPML import/export, cross-device sync , and no subscription lock-in —is tricky because true cross-device sync usually requires a cloud backend, which companies love to gate behind recurring fees.

However, open ecosystems and gPodder-compatible setups solve this gracefully. Here are the top choices that fit your criteria:

1. AntennaPod (Android) + gPodder Sync

• Private RSS / Auth Feeds: Fully supported (just paste the custom RSS feed URL, including tokenized/secret URLs or HTTP basic auth).
• OPML Import/Export: Fully supported.
• Cross-Device Sync: Supported via gPodder (you can use the free official gPodder.net service or host your own personal gPodder server via Nextcloud/Docker).
• Subscription / Lock-in: Free and Open Source (FOSS) . No ads, no data tracking, and no paywalls.
• The Catch: It is Android-only. If you need cross-platform sync between iOS and Android, this won't cover the iOS side.

2. Podget / gPodder-based desktop/mobile combos

• Private RSS / OPML: Standard across gPodder clients.
• Cross-Device Sync: By connecting multiple clients (like AntennaPod on Android and gPodder on desktop) to a gPodder sync backend, your subscriptions and playback states sync without paying a software subscription.

3. Pocket Casts (Free Tier)

• Private RSS / OPML: Supports OPML import/export and private RSS URLs (via "Add URL" in the search/add menu).
• Cross-Device Sync: Cross-device sync (web, Android, iOS) is included in their free tier.
• Subscription / Lock-in: While they have a "Plus" tier for extra themes, cloud file storage, and watch apps, core cross-device syncing and custom RSS feeds do not force a paid subscription.
• The Catch: Pocket Casts is a freemium commercial product (owned by Automattic), so while you aren't locked into a subscription for basic sync, it is not a pure FOSS/privacy-first project.

If you want to narrow this down, tell me:

• What operating systems are you trying to sync across (e.g., Android-only, iOS + Android, or Desktop + Mobile)?
• Are you open to self-hosting a sync server, or does it need to work out-of-the-box with existing free cloud services?

I can give you a precise setup guide for your specific device ecosystem.