// Compare
Nerva vs Pulsoid vs HypeRate.
Three ways to put your live heart rate on a stream. They split on two things you actually feel mid-stream: how fast the number reacts, and how much you can make the overlay your own. Here's an honest breakdown, including where the other tools are the better choice.
| Feature | Nerva Local-first · direct BLE | Pulsoid Cloud · phone | HypeRate Cloud · multi-device |
|---|---|---|---|
| Latency | None you can perceive. Direct BLE connection; your heart beats, the overlay moves. | Cloud round-trip adds a noticeable lag between the beat and the screen. | Cloud round-trip adds lag, even when the sensor is read locally. |
| How it connects | Strap/watch → app → overlay, all on your machine. One hop, no server in the middle. | Sensor → phone app → Pulsoid cloud → browser-source widget. | Sensor → app / Web Bluetooth → HypeRate cloud session → browser-source widget. |
| Phone required | No. The desktop app pairs with the sensor over BLE directly. | Yes, typically. The phone app bridges the sensor to the cloud. | Often, via the phone app, or browser Web Bluetooth / desktop app. |
| Customization | Fully customizable. Overlays are open HTML/CSS/JS; edit them or write your own from scratch. | Configure preset widgets (colors, fonts, ranges). No code-level control. | Pick and tune preset widgets. No code-level control. |
| Stress, not just BPM | Derived stress score from HRV (RMSSD, SDNN, pNN50, Baevsky index). | Raw BPM and zones. No derived HRV stress index. | Raw BPM and metrics. No derived HRV stress index. |
| Apple Watch | Not supported; it doesn't broadcast BLE heart rate. | Supported through the phone app. | Supported through the phone / watch app. |
| Platforms | Native app for Windows, macOS (Apple Silicon), Linux. | Phone app + any OBS/Streamlabs on any OS. | Phone, watch, desktop, and Web Bluetooth. |
| Price | 1-month free trial, then €90/yr or €10/mo. Funds active upkeep by one dev. | Free tier; paid plans unlock advanced widgets and integrations. | Desktop app and Web Bluetooth are free and open-source. The mobile app (used for Apple Watch and most phone setups) needs a subscription: $3.99/mo or $19.99/yr. |
Competitor capabilities change often. Last reviewed June 2026 against the vendors' own sites. Corrections welcome at support@nervabio.com.
// The honest version
Pulsoid and HypeRate are good tools with real strengths. Pulsoid has the widest widget and integration ecosystem and a generous free tier. HypeRate supports an enormous range of devices, ships an open-source desktop app, and its desktop and Web Bluetooth paths are free, though the mobile app you'd use for an Apple Watch is a subscription ($3.99/mo or $19.99/yr). If those are what you're optimizing for, they're the right call, and this page won't pretend otherwise.
Nerva makes a different trade. It's a paid, native desktop app built around three things the others don't center:
No lag
Nerva connects to your BLE strap or watch directly and draws the overlay on your machine. There's no cloud in the path, so the number moves the instant your heart does. The others send the signal to their servers first.
Fully customizable
Overlays are open HTML/CSS/JS folders that read live values as CSS variables. Restyle a bundled one or build your own. The others give you preset widgets to tune, not the markup itself.
Stress, not just a number
Nerva derives a stress score from heart-rate variability (RMSSD, SDNN, pNN50, Baevsky index), so the overlay reflects what your body is doing, not only how fast your heart is beating.
It also needs no phone, and runs as a small native app (under 10 MB of RAM). It's local too, so nothing about your heart rate touches a server, but on stream the reason that matters is the lack of lag, not privacy.
Which one should you pick?
Pick Pulsoid
if you want the biggest library of widgets and integrations (Discord, Stream Deck, Voicemod), and you're fine with a cloud-routed, phone-bridged setup.
Pick HypeRate
if you want the widest device support, or a free overlay through its desktop app or Web Bluetooth (the mobile app, including Apple Watch, is a paid subscription).
Pick Nerva
if you want the overlay to react with no cloud lag, to fully customize how it looks (or commission a bespoke one), and to read real stress, not just BPM, and you're happy to pay a small subscription that keeps a one-person tool maintained.
Prefer a head-to-head? For a deeper one-on-one, including what switching involves, see Nerva vs Pulsoid or Nerva vs HypeRate.
// FAQ
Alternatives, answered.
What's the best Pulsoid alternative?
If you're leaving Pulsoid because of the lag (the cloud round-trip between your heartbeat and the screen), Nerva is the closest fit. It reads your BLE strap or watch directly on the desktop and renders the overlay locally, so the number moves the instant your heart does, and you can rebuild the overlay however you like. Pulsoid's strength is its large widget and integration ecosystem (Discord, Stream Deck, Voicemod) and a free tier, so if those matter more, Pulsoid is still a fair pick.
What's the best HypeRate alternative?
HypeRate supports a huge range of devices, and its desktop app and Web Bluetooth paths are free. Worth knowing: the mobile app, which is how you connect an Apple Watch or most phones, is a subscription ($3.99/mo or $19.99/yr), so 'free' and 'Apple Watch' don't fully overlap. Nerva differs on three things streamers feel: it connects directly to the sensor so there's no cloud lag, the overlay is fully customizable code (not a preset widget you only tune), and it derives a stress score from heart-rate variability instead of only showing BPM. If instant reaction, full overlay control, and a real stress reading matter to you, Nerva is the alternative. If the widest device support is decisive, HypeRate is hard to beat.
Which heart-rate overlay has the lowest latency?
Nerva, because there's no cloud in the path. It talks to your BLE sensor directly and draws the overlay on your own machine, so the delay between a beat and the overlay reacting is effectively the BLE link itself. Pulsoid and HypeRate route the signal through their servers to render the widget, which adds a round-trip you can notice on a tense moment.
Can I fully customize the overlay?
With Nerva, completely. Overlays are open HTML/CSS/JS folders that read live CSS variables (BPM, stress, zone): you can restyle a bundled one, or write your own from scratch and package it as a .nerva-overlay. Pulsoid and HypeRate let you configure preset widgets (colors, fonts, ranges) but not edit the overlay as code. If you want a look that's truly yours, or a fully bespoke one, that's a custom overlay commission.
Is there a heart-rate overlay that shows stress, not just BPM?
Yes, that's Nerva's main differentiator. Alongside live BPM it computes heart-rate-variability metrics (RMSSD, SDNN, pNN50) and a Baevsky-style stress index, and exposes them to overlays as live CSS variables. A chest strap (e.g. Polar H10) gives the most accurate HRV; a watch gives reliable BPM.
Why is Nerva paid when Pulsoid and HypeRate have free tiers?
Both have free paths (Pulsoid's free tier, HypeRate's desktop app and Web Bluetooth), though HypeRate's mobile app, used for Apple Watch and most phones, is itself a subscription. With Nerva you're not really paying for an app, you're paying to keep it maintained. It's built by one person, with no cloud to monetize, no ads, and no data to resell, so a subscription is what funds the bug fixes, new overlays, and device support over time. In return you get the things the free tools don't do: a direct, no-lag connection, overlays you can fully customize as code, and an HRV-based stress score. There's a 1-month free trial (no card, no account) so you can decide before paying.
Do I need a phone to put my heart rate on stream?
Not with Nerva. The desktop app pairs with your BLE strap or watch directly. Pulsoid usually relies on its phone app to bridge the sensor to the cloud. HypeRate can use a phone app, a smartwatch app, or browser Web Bluetooth.