// Heart-rate overlay for OBS
Put your heart rate in OBS, with no cloud lag.
A local browser-source overlay that shows your live BPM on stream. Direct BLE, no phone, no server in the path, so the number reacts the instant your heart does. Works with OBS, Streamlabs, or any browser source on Twitch, YouTube, and Kick.
// Setup
Heart rate in OBS, in four steps.
- 01
Pair your heart-rate sensor
Open Nerva and pair your BLE chest strap or watch (Polar, Garmin, COROS, Amazfit, Wear OS). No phone, no account, no cloud session.
- 02
Pick or edit an overlay
Choose a bundled overlay or open its HTML/CSS/JS and restyle it. Overlays read live BPM, stress, and zone as CSS variables, so you control exactly how they look.
- 03
Copy the local browser-source URL
Nerva serves the overlay from your own machine and gives you a local URL. Nothing leaves your computer.
- 04
Add a Browser source in OBS or Streamlabs
In OBS or Streamlabs, add a Browser source and paste the local URL. Size it, position it, and your live heart rate is on stream, reacting with no cloud round-trip.
Full data API, CSS variables and packaging are in the overlay docs.
-
No cloud lag
The browser source reads a local server, not a cloud session. The BPM reacts as fast as the BLE link.
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No phone needed
Nerva pairs with your BLE strap or watch directly from the desktop, nothing to bridge.
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Fully customizable
Bundled overlays are open code, or add a stress / HRV readout alongside the BPM.
// FAQ
Heart-rate overlay for OBS, questions.
How do I add a heart-rate overlay to OBS?
Pair your BLE strap or watch with the Nerva desktop app, pick or edit an overlay, copy the local browser-source URL Nerva gives you, then add a Browser source in OBS and paste it. Because Nerva renders the overlay on your own machine, there's no cloud round-trip, so it reacts the instant your heart does.
Does it work with Streamlabs too?
Yes. The overlay is a standard local browser source, so anything that accepts an OBS/Streamlabs browser source works: Streamlabs Desktop, OBS Studio, and similar.
Will it show up on Twitch, YouTube, and Kick?
All of them. The overlay lives inside your OBS/Streamlabs scene, so whatever you stream to, the heart rate is baked into the broadcast. It's platform-agnostic by design.
What heart-rate sensors work?
Any device that broadcasts the standard BLE Heart Rate Service (UUID 0x180D): chest straps like the Polar H10, and watches from Garmin, Polar, COROS, Amazfit, and Wear OS (via 'Heart for Bluetooth'). A chest strap gives the most accurate reading. Apple Watch is not supported, because it doesn't broadcast BLE heart rate.
Why not just use a cloud heart-rate widget?
Cloud tools send your heart rate to a server before the widget updates, which adds a round-trip you can feel on a tense moment. Nerva connects to the sensor directly and draws the overlay locally, so there's no lag, no phone bridge, and no third-party broker between your strap and your stream.
Can I customize how the overlay looks?
Completely. Overlays are open HTML/CSS/JS folders that read live values (BPM, stress, zone) as CSS variables. Restyle a bundled overlay, write your own from scratch and package it as a .nerva-overlay, or commission a bespoke one.