Show HN: Castream – Native iOS/Android IRL multistreaming app

Hey HN,

I just launched the iOS version of Castream, a native app that lets you multistream directly from your phone to platforms like Twitch, YouTube, Facebook, and any custom RTMP endpoint. Android has been live for a bit — iOS just went up this week.

This was built to solve the usual pain points of mobile streaming: unreliable apps, no multistream support, or being forced to go through a PC. Castream uses native encoding and streams straight from your phone using real RTMP — no browser wrappers or WebRTC hacks.

Some quick details: • Native iOS and Android apps (hardware-accelerated video/audio encoding) • Multistreaming with your own RTMP keys • Free plan supports 720p to two destinations, up to 5 minutes per stream • Paid plans unlock 1080p, more destinations, unlimited stream time, and other features • Backend is FastAPI, using FFmpeg on-device for muxing/streaming • Built this solo — full stack + native mobile (Swift/Java/Kotlin)

We’re currently getting early sign-ups mostly through organic reach — haven’t spent anything on ads yet, just trying to get real users and feedback.

Links: iOS: https://apps.apple.com/app/castream/id6747093725 Android: https://play.google.com/store/apps/details?id=io.castream.ap... Website: https://www.castream.io

Would love any feedback — especially from folks building in video, streaming infra, or native mobile.

Thanks.