EVERY APP HERE RUNS WITHOUT A SERVER

Apps that don't
watch back.

See the apps
01 THE LAB

The apps

All four of these you can install today.

LIVE
🔒

Whispr

PRIVATE BY DEFAULT

Whispr runs the Signal Protocol over your LAN, or over Tor when you are not on the same network. With no network at all it goes by Bluetooth, hopping phone to phone until it reaches the right person, which took about an hour over a distance under 5 km. Your identity is a key the app generates on the phone.

Explore→
LIVE
❤️

Heart

LOCAL-FIRST WELLNESS

A wellness app for Bluetooth heart-rate bands. HR, HRV, sleep stages, recovery and strain, on the phone. No band, nothing to read.

Explore→
V1
🪢

Knot

PEER-TO-PEER VERSION CONTROL

Save a file. Knot waits until you stop typing, then makes a real commit. That commit goes to every paired machine over Tor.

Explore→
OPEN MODEL
✍️

Knot AI

TWO ON-DEVICE MODELS

Knot Scribe writes commit messages. Knot Delta explains what changed, and it pins the exact line 52 to 74% of the time, lowest on Rust. The weights are on Hugging Face and Ollama.

Explore→
02 PROOF

What holds for every app here

Whispr, Heart and Knot were built without a server behind them. Knot was the hard one, because peer-to-peer version control is where a central server would have been the easy answer.

stack.txt
Storage → SQLCipher · AES-256 · full-file encryption · on device
Server → None · peer-to-peer or local-only by design
Accounts → None · no email, no phone, no registration
Telemetry → None · no analytics, no crash reports, no usage pings
Trust model → Published algorithms · you cannot rebuild the binaries yourself
Per-app cryptography (Whispr's Signal Protocol stack, etc.) →
03 THE STUDIO

About PointBreakLab

I started with Whispr. I wanted a chat app where nobody has to be scared someone is watching. Every one I found runs through a server, so Whispr has no physical server and your data stays with you. The website exists because Whispr needed a home.

The name was trouble. Nothing fit for a long time, then I heard Point Break in an Avengers film and liked it enough to keep it. Lab I mean literally. None of these apps happened by fluke and each one has research behind it. I believe one day people will look into it and recognise PointBreakLab.

Heart I built for myself, off a cheap Coospo HW9 chest strap, to read my own body data. Then Knot, version control where your code belongs to your machine. There is honestly too much built here now and I keep shipping updates. They are free.

GitHub identicon avatar of Roshan Kumar Gupta

Roshan Kumar Gupta

Student · builds and ships everything here

Julius-Maximilians-Universität Würzburg Julius-Maximilians

📍 Würzburg, Germany

Map showing Würzburg, Germany

© OpenStreetMap contributors

Building in public
04 UPDATES

Both of June's updates were Knot

New entries land here when something ships, which is not often.

KNOT

Jun 2026

Knot is here

Syncs a folder between machines over Tor, and the two ends talk straight to each other. Mac and Linux, free on the Knot page.

KNOT

Jun 2026

Follow Knot from your phone

A phone app that mirrors every synced repo read-only over the LAN, so you can keep an eye on the work from anywhere in the house.