Castport vs Transistor: Open Source vs Subscription

OneTimeSuite Blog · Published 2026-07-21

Castport and Transistor solve the same problem from opposite directions: one is source-available software you can own outright for $39, the other is a subscription at $19/mo run entirely on someone else's servers.

Head to head

What Castport does well

• Unlimited shows & episodes — Each show gets its own artwork, iTunes category, language, explicit flag and custom feed slug. No per-show pricing tiers.
• Apple/Spotify-valid RSS — RSS 2.0 with the full itunes namespace, exact enclosure byte lengths, permanent GUIDs and valid pubDates — the details that actually get feeds rejected, done right.
• Streaming uploads — MP3 or M4A streamed straight to disk — no buffering 200 MB files in memory — with markdown show notes, episode/season numbers and per-episode artwork.
• Podcasting 2.0 chapters — A chapters editor (start time + title) that also emits the podcast:chapters JSON endpoint modern apps read.

What Transistor still does better

You do — that's the honest trade-off of self-hosting. A $5 VPS comfortably serves a typical indie show; a genuinely huge audience is where Transistor's managed CDN infrastructure earns its monthly fee.

Which one should you pick

If your workflow depends on Transistor's specific integrations or you'd rather not run anything yourself, stay put — that's a legitimate call. If you're comfortable owning the tool and want to stop paying $19/mo for a job your own hardware can do, Castport pays for itself and then some: pays for itself in 2.1 months against Transistor Starter — or under a month against Growth. Over 3 years you keep $645–3,525.