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Open-source Castr alternative

One open-source alternative to Castr, with its features, GitHub activity and licence.

The open-source alternative to Castr listed on Enlisted is Ant Media Server.

Ant Media Server is listed under media & streaming tools. It shipped code in the last 30 days and can be self-hosted.

Last updated October 3, 2026 · ranked by GitHub stars, growth and recent commits

Ant Media Server

A scalable media server for live streaming with WebRTC, SRT, RTMP, HLS and CMAF, with SDKs for mobile and web and Community and Enterprise editions.

GitHub stars
4.7k
Last commit
yesterday
Latest release
ams-v3.1.0
Self-hosted
Yes
antmedia.ioAnt Media Server homepage screenshot

Ant Media Server is a scalable media server for low-latency live streaming. It supports WebRTC with a claimed latency of about half a second, along with SRT, RTMP, RTSP, HLS and CMAF low-latency HLS, and also handles H.265/HEVC. Developers use it to build real-time video applications and live broadcasting.

Capabilities include adaptive bitrate workflows, transcoding, recording and cloud auto-scaling. SDKs are provided for iOS, Android, React Native, Flutter, Unity and JavaScript, and security features include SSL/TLS, token authentication, IP filtering and watermarking. The README lists use cases such as telehealth, e-learning, sports streaming, auctions and interactive applications.

The project is split into a Community edition with the essentials and an Enterprise edition that adds advanced features and support, and a free trial of the Enterprise edition is offered. It is written in Java, and documentation covers installation, API references and tutorials.

Key features

  • Low-latency WebRTC streaming
  • SRT, RTMP, RTSP and HLS support
  • CMAF and low-latency HLS
  • Adaptive bitrate and transcoding
  • Recording and cloud auto-scaling
  • SDKs for iOS, Android, Flutter and JavaScript
  • Token authentication and IP filtering

Pricing: Self-hosted Enterprise licenses cost $109 per instance per month, $89 on an annual subscription, $0.24 per instance-hour, or $2799 perpetual. Cloud marketplace listings start at $0.33 per hour, with trials.

Castr alternatives: questions

What is the best open-source alternative to Castr?
Ant Media Server is the only open-source alternative to Castr listed on Enlisted so far: A scalable media server for live streaming with WebRTC, SRT, RTMP, HLS and CMAF, with SDKs for mobile and web and Community and Enterprise editions.
Is Ant Media Server free?
Ant Media Server is open source, so the code is free to use under its licence, and it can be self-hosted on your own server or computer.
How does Enlisted rank Castr alternatives?
By a score built from GitHub stars, star growth over the last 30 days and how recently the code changed. Ant Media Server shipped code in the last 30 days. Data is refreshed daily, and nobody can pay to move up.

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