Synheart's infrastructure is live. On-device inference is free, forever.
Synheart's infrastructure is live. On-device inference is free, forever.
SYNHEART DEVELOPERS
Synheart’s developer ecosystem is one open standard, a set of native SDKs, and the tooling around them — everything you need to read structured human state in your product. Install one SDK, add the pieces your product needs, and skip the ones it doesn’t.
WHAT WE BELIEVE
Everything in the ecosystem exists to do one job: turn raw signal into a structured read on human state your app can act on. Signals come in from a wearable, a digital device, or both. SDKs normalize and process them on the device. Your app reads one consistent output HSI no matter where the signal came from.
OUR PRINCIPLES
An open, versioned format for human-state data: a score, a confidence value, and the moment it applies to. Everything below produces or consumes it.
Read raw signals and normalize them: Wear covers wearables (heart rate, HRV, activity), Behavior covers interaction patterns from digital devices — timing, rhythm, and pattern, never content.
The single SDK most teams install first. Connects a signal source, runs on-device inference, and delivers structured HSI your app reads directly.
Syni LLM is a state-aware language model that shapes its responses to how someone is actually doing. SWIP is a repeatable score for the impact your product has on the people using it.
Auth signs every request with hardware-backed device identity. Platform is the console for keys, usage, and billing. The CLI is where most integrations start.
Every layer is modular. A focus-only product on Core SDK alone is a normal, supported setup so is a wearable only product on Synheart Wear standalone.
DEVELOPER PLATFORM
The HSI stack. Each layer is open and composable, from raw signal to a portable human-state contract that any system can read.
The Portable Contract For Human State.
A lightweight model running entirely on-device classifies physiological stress states from wrist-based signals with 74.5% accuracy, comparable to chest-based methods while preserving full user privacy. Validated on the WESAD dataset.
Open Source
Connect Any Wearable. Stream Biosignals.
The sensing layer. Connects WHOOP, Garmin, Apple Watch, Fitbit, and Pixel Watch, and standardizes HR, HRV, EDA, and motion into one real-time stream. Local preprocessing and a developer CLI included.
Open Source
Read How People Interact, Never What They Write.
Converts interaction dynamics such as timing, rhythm, and fragmentation into structured behavioral metrics. Content-free and identity-free, fully on-device.
Open Source
One SDK, Every Signal Source
A modular, on-device SDK that fuses multimodal signals into the Human State Vector. Modules for Wear, phone, and Behavior, with focus and state inference on top
Open Source
The Console For What You Build
The developer portal for API keys, routing, logs, and data export. Where teams manage everything they build on HSI.
Live
On-Device State Inference, Research-Grade.
A lightweight, uncertainty-aware research model that infers probabilistic human state from physiological signals such as HR, HRV, and motion. Built for ethical, defensible, on-device research.
ResearchSEE IT IN ACTION
Watch a raw signal become human state, and see how the apps put it to work.
TOOLING
Everything starts from the terminal: mock signal streams before you have hardware, local consent and ingest endpoints for offline testing, deterministic SDK artifact installs and mcp serve, which exposes CLI verbs as MCP tools for AI coding agents.
The console for what you build: API keys, usage, billing, and team access in one place. Governs access and delivery never runs your inference.
Guides, references, and integration walkthroughs for every SDK at docs.synheart.ai.
FROM ZERO TO FIRST OUTPUT
Install the CLI and generate a mock signal stream. See what Synheart actually returns before writing a line of app code — no hardware, no account required.
Add the package for your platform and point it at a signal source. Wear, Behavior, or the CLI’s mock stream all work.
Subscribe to the state stream and read structured values — focus, stress, recovery, each with a confidence value attached.
BUILDERS PROGRAM
The Builders Program is for teams shipping on Synheart’s infrastructure early direct access to the team, early SDK builds, and input on the roadmap.
Apply to the Builders Program
FAQ
Free for on-device use. No account required to start.
