u/Abdul_Saheel

Hi everyone! I'm looking to buy a WHOOP 5.0 without a subscription requirement. If anyone is looking to sell theirs, please let me know. Thanks!

Location: Anywhere in Hyderabad.
Price : Variable

I'm looking to buy one for development and testing. I'm the developer of OpenStrap, an open-source companion app for WHOOP. It currently supports WHOOP 4, and many users have been asking for WHOOP 5 support. I'd really appreciate any help from the community in finding one.

Made this over the last couple of months: an app that pairs with a WHOOP fitness band, pulls the data straight off it over Bluetooth, and shows you your sleep, heart rate, HRV, strain and recovery — no WHOOP membership needed.

The idea was simple — the band still works fine when a subscription lapses, it just goes dark because only their app talks to it. So I reverse-engineered how it communicates and built a full little stack: the phone app, a backend that crunches the numbers, and the protocol decoders. All open source (MIT). You can even self-host the backend so your health data stays on your own machine.

It's not a WHOOP replacement and doesn't try to be — just a way to keep a band you own useful. Tested on the 4.0, and there are still rough edges I'm working through.

Main repo (the app): https://github.com/OpenStrap/edge — everything else under https://github.com/OpenStrap

If you're a dev and found this useful or interesting, a ⭐ on the repo genuinely helps. And if you've got a WHOOP 4.0 lying around, please try it and open an issue on GitHub if anything feels off — that's how it gets better.

Been chipping at this side project for a couple of months and finally got it to a state worth sharing.

The itch: my WHOOP band generates all this data 24/7 but you can't touch any of it without their app and a subscription. So I figured out how it talks over Bluetooth and built a thing that reads it directly — a phone app that pairs with the band and drains it, a backend that stores the data and computes the metrics (sleep, resting HR, real HRV, rough strain/recovery), and the protocol decoders underneath.

It's four small repos (app, backend, analytics, protocol), all MIT. Not trying to be a WHOOP replacement — their analytics are years of real research — just a way to keep using a band you already own, with your data on infrastructure you control (you can self-host the backend).

Honest about the rough edges: tested on WHOOP 4.0 only, and the UX still has gaps. But it works end to end.

Main repo (the app): https://github.com/OpenStrap/edge — rest under https://github.com/OpenStrap

If you're a dev and found this useful or interesting, a ⭐ on the repo genuinely helps. And if you've got a WHOOP 4.0 lying around, please try it and open an issue on GitHub if anything feels off — that's how it gets better.

I know, I know , you've heard of posts like this plenty of times before. Stay with me on this one.

First, so it's clear where I'm coming from: I'm not knocking WHOOP. The product is genuinely good, and the recovery/strain/sleep work behind it is years of research I have zero interest in pretending I can match. This isn't a "WHOOP bad, use mine" post.

It's about the band itself. When a membership lapses, the hardware is basically useless, You Own it, You still cant use it, it just goes dark, because the app stops talking to it. So you've got a perfectly good sensor turning into a paperweight. That's the only thing I set out to fix.

I spent a few weeks reverse-engineering how the 4.0 talks over Bluetooth, how it streams data, how to acknowledge its events so it keeps sending, how to capture and parse all of it. and built a small open-source stack around it. I tested the decoded values in different situations (wearing it, off-wrist, charging, workouts) and checked them next to my Apple Watch Ultra 1 to make sure they line up. I'm fairly confident in them, though I'll say plainly I'm not claiming 100% certainty on everything.

It's four open pieces:

• protocol — the decoders for the strap's raw records.
• backend — a small server that stores the raw data and computes metrics (one Cloudflare Worker).
• analytics — the math, using only published, proven formulas (Banister TRIMP for strain, Cole-Kripke for sleep, RMSSD for HRV, Keytel for calories). No magic, no claims of being WHOOP's algorithms.
• edge — the phone app (Flutter) that pairs with the strap and shows you your day.

The honest part, because this community cares about accuracy: these are rough approximations from the data the band actually exposes. They are not WHOOP's numbers and I'd never present them as such. If you have an active membership and you're happy with it, honestly just keep it, this isn't meant to pull you away from it.

Where I think it's actually useful:

• Your 4.0 is retired and you'd rather use it than bin it.
• You'd prefer your health data not sit on a company's servers, you can self-host the entire backend yourself, so it never leaves a machine you own. Or just ask claude to do it for you.
• You just like tinkering with open source.

Some real caveats, up front:

• No background sync yet — the app only pulls from the strap while it's open, so you have to actually open it.
• No proper notification system yet.
• Tested only on the WHOOP 4.0.
• Heads-up: if you do use this, I'd avoid reconnecting the strap to the official WHOOP app afterward, a firmware update could change the events this depends on. So this really is best for a band you're no longer running on a membership.

It's open source under MIT. If you've got a retired 4.0, give it a week and let me know how it goes , feedback is what makes it better.

I did some searching before posting this, and I genuinely believe this is the closest thing out there to actually being called a fitness app, not just a protocol demo. It's your choice to make in the end, but I'd really request you give it a try and raise an issue on GitHub if you notice anything wrong or something feels off. That's how it gets better.

Main repo (the app): github.com/OpenStrap/edge . Everything else is under github.com/OpenStrap.

Happy to answer questions.

TL;DR: I have made a whoop compatible fitness app which works without subscription and you can download it from github releases

I travel back to my hometown most weekends and holidays, so I live by RTC buses. The official Gamyam app is genuinely painful, slow, buggy, crashes when you switch screens.

Last week it died on me while I was tracking my friend's bus at the stand, and I decided enough is enough. So I ( and claude , ofc) spent a day building a better one.

TGSRTC Bus Live Tracking : A clean, fast app that actually

- stays on the bus (the official one snaps back to an old spot every refresh — you had to re-zoom every single time)
- proximity alarm -  get notified when your bus is within ~1 km of your stop, so you can stop staring at the screen
- Live speed, status (moving/halted), next stop
- On iPhone: a lock-screen Live Activity + Dynamic Island so you can track without even opening the app

It's not official, not affiliated with TGSRTC. It uses the same public bus-location data their app does, just with a UX that doesn't make you want to throw your phone. Free, no ads, no login.

Do not completely rely on this app as this is built overnight and lot of testing is yet to be done, but Just give it a try this time when you travel by TGSRTC , Would love the honest feedback, even if its brutal , Heres the direct link to the app