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Health technology, privacy-first design, and the research behind what a ring can actually measure.

A simple budget fitness tracker on a wrist, representing the low-cost wearable hardware that Pebble and independent smart ring makers are building

Latest Wearables Pebble's $75 Index 01 and the Great Smart Ring Divergence The smart ring market is splitting into three species: premium health platforms, single-purpose tools, and subscription-hungry AI wrappers. Pebble's Index 01 proves the divergence is real. James Hoffmann May 26, 2026 12 min read Read article

Why Stress Scores Are the Most Fabricated Metric in Wearables James Hoffmann May 26, 2026 13 min read

What HRV Actually Measures and Why Your Recovery Score Is a Marketing Invention HRV is not a score. It is a noisy physiological signal that consumer wearables clean, compress, and repackage as a recovery percentage with no medical validation. This post explains how the sausage is made, why the math does not support the marketing, and what Pulsyn does instead. James Hoffmann May 26, 2026 12 min read

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LATEST ARTICLES

A close-up of a smartphone processor chip, the same hardware that runs Pulsyn's on-device health AI without ever sending your biometrics to a server

How On-Device AI Actually Works: Why Your Health Data Never Leaves Your Phone On-device AI means your health data never leaves your phone. Here is the architecture, the constraints, and why it makes subscriptions unnecessary. James Hoffmann May 25, 2026 13 min read

A dark metallic smart ring on a textured surface, representing the last independent hardware in an industry racing toward subscriptions

The No-Subscription Smart Ring Is Not Dead. The Industry Just Wants You to Think So. Oura filed for IPO. RingConn got pulled from Amazon. Ultrahuman and Luna are banned in the US. A Reddit user asked if the no-subscription smart ring dream is dead. It is not. But the remaining options are smaller, founder-led, and built on economics that venture capital hates. James Hoffmann May 25, 2026 11 min read

A digital lock concept representing how wearable companies trap user health data behind proprietary APIs and subscriptions

The API Trap: How Wearable Companies Make Your Health Data Disappear When You Cancel Most wearable APIs are not built for you. They are built for partners who build features that keep you subscribed. Here is how the data lock-in actually works, and how Pulsyn does the opposite. James Hoffmann May 24, 2026 13 min read

View through an airplane window at night, representing the disconnected environments where most health trackers fail but Pulsyn keeps working

Your Sleep Tracker Should Work on a Plane. Ours Does. Most health trackers treat your phone as a dumb pipe to their cloud. When you turn on airplane mode, the app becomes a brick. Pulsyn's architecture assumes the opposite: your phone is the computer, the database lives locally, and the cloud is an optional extra. James Hoffmann May 23, 2026 13 min read

A dark abstract visualization of encrypted data streams and digital security

How Pulsyn Encrypts Your Health Data: SQLCipher, 600,000 PBKDF2 Iterations, and Why We Do Not Know Your PIN A technical deep-dive into Pulsyn local-first encryption stack: SQLCipher, AES-256-GCM, 600,000 PBKDF2 iterations, and why we intentionally cannot recover your data if you lose your PIN. James Hoffmann May 22, 2026 11 min read

A close-up of a smart ring on a finger, representing the wearable health tracking market Oura dominates but may not hold

Oura Just Filed for IPO. Here Is Why It Will Flop. Oura filed for its $11 billion IPO with 5 million subscribers and $2 billion in projected revenue. The catch: its core business model is a subscription paywall on health data that competitors already offer for free, sitting on top of a canceled Pentagon contract and an active class-action lawsuit. James Hoffmann May 22, 2026 12 min read