If you have set up a live stream, you have probably seen the terms "RTMP URL" and "stream key". RTMP is the protocol that sends your video from your camera or encoder to the streaming platform. Here is what you need to know.
What RTMP stands for
RTMP stands for Real-Time Messaging Protocol. It was originally developed by Macromedia (later Adobe) for sending video, audio, and data over the internet in real time. It has been around since the early 2000s and remains the most widely used protocol for ingesting live video.
When you stream, your encoder packages your video and audio into an RTMP stream and sends it to the platform server. The server then transcodes and distributes it to viewers via HLS or another playback protocol.
How you use it
When you create an event on a streaming platform, you receive two things: an RTMP URL (the server address) and a stream key (your unique identifier). You paste both into your encoder, whether that is OBS Studio, a hardware encoder, or a mobile app.
Once you start streaming, your encoder connects to the RTMP URL and begins sending data. The stream key tells the server which event the data belongs to.
RTMP vs other protocols
SRT (Secure Reliable Transport) is a newer protocol that handles unreliable networks better than RTMP. Some platforms now accept SRT input as well as RTMP. If your encoder supports SRT and your platform accepts it, SRT is generally the better choice for streaming over unstable connections.
For most community and grassroots streamers, RTMP works perfectly well. It is supported by virtually every encoder and every platform, which makes it the safe default.
Just paste and stream
PassCast gives you an RTMP URL and stream key for every event. Paste them into OBS, your encoder, or any RTMP-compatible app and go live.
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