RTMP vs RTMPS for streaming: Why FastPix Chooses RTMPS

If you’ve ever set up a live stream, chances are you’ve run into the streaming protocol called RTMP. It’s been the backbone of live video delivery since the Flash days, and even though Flash itself is long gone, the protocol stuck around because it just works. Point your encoder to an RTMP URL, hit “Go Live,” and your video is on its way.

But lately, another acronym has been showing up: RTMPS. At first glance, it feels like one of those subtle tech distinctions you could ignore. One has an extra “S,” so what? The reality is that the “S” - for Secure - decides whether your stream travels over the internet in the clear or wrapped inside the same kind of encryption that protects online banking.

This isn’t just a theoretical upgrade. Platforms from Facebook Live to YouTube now recommend or even require RTMPS, and for good reason: it closes off a class of vulnerabilities that plain RTMP leaves open.  

Here’s a quick side-by-side view of RTMP and RTMPS to set the stage before we dive deeper:

‍

‍

In this post, we’ll walk through what both protocols actually do, where they fit into modern streaming, and why that single letter can mean the difference between a reliable broadcast and an exposed one.

‍

What is RTMP?

When you hit “Go Live” in OBS, vMix, or any other encoder, something has to carry that stream out to the wider world. That’s where RTMP (Real-Time Messaging Protocol) comes in. It’s the protocol that takes your video and audio and pushes it to a server, where it can be turned into the formats your viewers actually watch.

The reason RTMP stuck around so long is simple: it just works. It creates a persistent TCP connection - usually over port 1935 - and once the handshake is done, that pipe stays open for as long as you’re streaming. Your video flows through in small, steady chunks, and the connection doesn’t constantly drop or renegotiate. For anyone running a live broadcast, that reliability is everything.

Because of this design, RTMP developed a few defining traits that made it indispensable in streaming workflows:

• Low latency: delivery happens close to real-time, ideal for live broadcasts.

• Persistent connection: keeps the stream running smoothly without frequent reconnects.

• Wide support: built into encoders, media servers, and ingest pipelines across the industry.

‍

How it works under the hood

If you peel it back, the mechanics aren’t complicated:

1. The client connects to the server (handshake + optional authentication).
2. Audio and video are encoded and split into small chunks.
3. Those chunks are sent over the open TCP connection.
4. The server ingests the data and typically passes it on to a CDN, where it’s repackaged into HLS or DASH for playback.

‍

Limitations of RTMP

Of course, RTMP wasn’t built for today’s internet. Some drawbacks are obvious:

• No encryption: Streams are sent in plain text, which leaves them open to interception. ‍
• Security risks: Without encryption, streams can be hijacked or altered in transit. ‍
• Limited Scalability: RTMP alone doesn’t handle very large numbers of viewers well without relying on CDNs, which adds complexity. ‍
• Port dependency: Port 1935 might be often blocked by some firewalls or restricted networks.

‍

So while RTMP is still the go-to for ingest - getting your stream into a platform — it’s no longer used for playback. Once the video hits the server, it almost always gets converted into something more modern, secure, and scalable.

That’s why today, RTMP is used mostly for ingest - getting a live feed into a platform - it’s no longer used for playback. Once it hits the server, the stream is repackaged into modern formats that scale better and meet today’s security expectations.

For a deeper comparison, check out our article on RTMP vs SRT.

‍

What is RTMPS?

If RTMP is the reliable protocol for live streaming, RTMPS is that same protocol with a security upgrade. The “S” stands for Secure, and what it really means is that every packet of audio, video, and data is wrapped inside SSL/TLS encryption as it moves from your encoder to the server. In practice, that shuts the door on eavesdropping and tampering while keeping the low-latency performance that RTMP was known for.

The beauty of RTMPS is that it doesn’t reinvent the workflow. It feels the same as RTMP - same real-time delivery, same persistent connection - but safer. In most cases, the only difference you’ll see as a developer is swapping ‘rtmp://’ for ‘rtmps://’ in your ingest URL.

‍

Technical specifications of RTMPS

RTMPS builds on the RTMP framework by integrating security features to ensure safe and encrypted data transmission. Here are its key technical details:

• Port 443 by default: RTMPS usually runs on TCP port 443, the same one HTTPS uses. That makes it much easier to slip through firewalls and strict network configurations.
• ‍SSL/TLS encryption: Every stream is encrypted, preventing unauthorized access, packet sniffing, or injection attacks.
• ‍Low latency preserved: Even with encryption overhead, RTMPS keeps the near real-time performance that live streaming demands.
• ‍Backend compatibility: If your workflow already uses RTMP, moving to RTMPS is seamless, no major re-architecture required to streaming infrastructure.
• ‍Stronger authentication: Handshakes can include secure credential checks, verifying that the client and server are who they claim to be.

‍

How RTMPS works

The RTMPS handshake and streaming process look like this:

‍

1. Connection & handshake

• Client connects to the server over port 443.
• SSL/TLS negotiation kicks in: the server shares its certificate, the client verifies it, and both sides establish a session key.

‍

2. (Optional) Authentication

• If credentials are required, they’re exchanged securely after the handshake.

‍

3. Encrypted data transmission

• Audio/video is encoded, broken into small packets, and encrypted with the session keys.
• Encrypted packets are pushed over TCP to the server.
• The server decrypts them, ready for processing or CDN handoff.

‍

4. Server & CDN integration

• The server forwards encrypted streams securely to CDNs.
• CDNs distribute to global viewers with minimal latency.

‍

5. Monitoring & session management

• The connection stays alive as long as the stream runs.
• If a drop happens, retry logic re-establishes the session securely.

‍

6. Secure session termination

• When the stream ends, the connection closes with a secure termination signal, and encryption keys, session information are wiped from memory.

‍

Advantages of RTMPS over RTMP

For most developers, the big reason to move from RTMP to RTMPS comes down to one word: trust. If your stream isn’t encrypted, you’re asking viewers to accept risks you can’t see but attackers can exploit. RTMPS fixes that without changing how you work.

Protection against MITM attacks

A Man-in-the-Middle (MITM) attack is exactly what it sounds like: someone slipping between your client and server to intercept or even alter the data being transmitted. With plain RTMP, this is entirely possible - the stream is sent in clear text.

RTMPS closes that gap. By wrapping every packet in SSL/TLS encryption, it ensures only the intended server can decrypt your data. The result is twofold: your stream can’t be tampered with, and your viewers know the video they’re watching is the one you actually sent. For live workflows where reliability and trust are everything, that matters.

Compliance with data security standards

Beyond attacks, there’s compliance. If you’re working in industries that touch GDPR, CCPA, PCI DSS, or any other regulatory framework, encrypted transmission isn’t optional - it’s required. RTMPS makes meeting those standards far simpler because encryption is built in from the start. All audio, video, and related metadata move securely, which means fewer audit headaches and reduced exposure in the event of a breach.

‍

Limitations of RTMPS

Of course, nothing comes free. RTMPS introduces trade-offs you should be aware of when designing your workflow.

Slight increase in latency

Adding SSL/TLS encryption does introduce extra processing. Each packet has to be encrypted and decrypted before moving along, which can add a fraction of a second to your stream. For most cases, that latency is negligible, but if you’re building ultra low-latency systems (think esports betting or live auctions), you’ll want to measure the impact.

Higher processing demands

Encryption also eats CPU cycles. On the server side, handling hundreds or thousands of encrypted streams can require more compute power. On the client side, weaker devices may struggle with playback if they’re already resource-constrained. For modern hardware, this isn’t a dealbreaker, but it’s a consideration at scale.

‍

‍

RTMP vs RTMPS: Key Differences

At the surface level, RTMP and RTMPS look almost identical - the difference is a single letter in your ingest URL. But under the hood, that “S” changes how secure, accessible, and compliant your workflow really is.

‍

Today, most platforms have already made the choice for you. YouTube, Twitch, and Facebook Live all require RTMPS, not because RTMP stopped working, but because secure ingest is now the baseline expectation. If the rest of the web has moved to HTTPS, live video has to follow.

‍

Why FastPix switched from RTMP to RTMPS

When we first started building FastPix, our live streaming product started with RTMP support. It was the quickest way to give early users a stable ingest option and get them streaming fast. But from the beginning, we knew the shift to RTMPS was coming - it was part of the roadmap, not an afterthought. Within a few months, we rolled it out as the default.

‍

1. Stronger security
RTMPS brings SSL/TLS encryption into the workflow, ensuring every stream is protected from interception the moment it leaves the encoder.

‍

2. Industry standards

With regulations like GDPR and CCPA setting a high bar for data security, building RTMPS in early meant our customers had compliance baked in from day one.

‍

3. Content integrity
RTMPS guarantees that streams reach the server exactly as they left the encoder — critical for anyone delivering premium or sensitive content.

‍

4. User trust
Making secure ingest the standard signalled to our users that privacy and reliability weren’t optional features, but core to the platform.

‍

5. Reliable access
By running over port 443, RTMPS avoids the firewall and browser issues that often trip up legacy RTMP traffic, keeping streams consistent across networks.

‍

How to Stream with RTMPS using FastPix

With FastPix, you can start an RTMPS live stream in two ways: directly from the dashboard for simple, one-off events, or using the Live Streaming API if you’re building secure live video into a product. Both approaches are designed to be quick to set up, with encryption and playback handled for you.

‍

Option 1: Stream from the Dashboard

If you just want to go live once - say for a webinar, event, or internal broadcast - the dashboard is the fastest route.

• Sign in to FastPix and create a new live stream.

• Copy the Stream Key and RTMPS server URL provided.

• Drop those details into OBS (or another encoder) and hit “Go Live.”

That’s it. FastPix ingests the RTMPS stream securely, and your broadcast is available to viewers via the provided playback URL.

Watch video: How live streaming dashboard works?

‍

Option 2: Stream with the Live Streaming API

If you’re building live streaming into your own app or platform, the API gives you full control. See detailed guide.

1. Generate an API Access Token
   Create an access token in your organization settings. You’ll use this to authenticate API requests.
   ‍

2. Create a Live Stream via API
   Make a POST request with your access token. FastPix responds with a Stream ID and Stream Key - these are what you’ll pass to your encoder.
   ‍

3. Start Broadcasting
   Point OBS (or your encoder of choice) to: “rtmps://live.fastpix.io:443/live”.
   Add the stream key you just generated. Once you hit start, FastPix switches the stream status to “active” and begins distributing it.
   ‍

4. Playback
   Every live stream comes with a unique Playback ID. Use that ID to generate an HLS playback URL like: “https://stream.fastpix.io/{PLAYBACK_ID}.m3u8”. You can embed this in your own player, or drop it straight into the FastPix Player SDK. See guide.
   ‍

5. Stop or Reconnect
   When you end the session in OBS, the stream automatically moves back to idle. If you gave it a reconnect window, FastPix will wait that long before closing the session.

For detailed API parameters and request and response examples, check the API Reference.

Watch video: How to live stream with RTMPS using APIs?

‍

Extra Features Built-In

• Automatic recording: Every live stream is recorded by default, so you can republish it as VOD or let viewers catch up later. ‍
• SRT support: Alongside RTMPS, FastPix also supports SRT ingest - useful for long-distance or high-jitter networks. Watch video. ‍
• Simulcast to social platforms: Stream once into FastPix, and broadcast to destinations like YouTube, Twitch, or Facebook Live at the same time. ‍
• Webhooks and events: If you’re integrating live streaming into an app, you can hook into FastPix’s event system to track stream status in real time.

‍

Wrapping up

At FastPix, we built RTMPS in from the start because secure live streaming shouldn’t be an afterthought. Every stream comes with encryption by default, playback-ready URLs, automatic recording, and the flexibility to simulcast to social platforms - whether you launch it once from the dashboard or integrate it deeply through the API.

The result is simple: you get all the infrastructure you need to deliver reliable, compliant, and production-ready live video, without spending weeks stitching it together yourself.

If you’re looking to add live streaming to your product or just need a quick way to go live securely, FastPix has both paths ready.

Try FastPix free with 25 credits → fastpix.io/signup

If you want to see it in action first, book a walkthrough with our team.

Want to build it yourself? → Explore the Live Streaming guide.