Seismofit

The data backbone behind a CE-marked, three-minute VO₂max test.

Ventriject’s Seismofit System estimates VO₂max in under three minutes without exercise. A compact chest sensor picks up the vibrations of each heartbeat, and an AI algorithm turns them into a result. We built the backend the product runs on.

IoTMedTech

Client: Seismofit
Sector: Medtech
Platforms: Cloud backend, Flutter app and web portal
Our role: Backend system
Period: Ongoing product partnership

What was the challenge?

The measurement has to be repeatable across clinics, devices and operators. Every recording needs to be tied to the right subject, device and operator, and the result has to be traceable back to the raw signal.

Product: Seismofit® System
Status: Live · CE-marked

What did bon.do build for Seismofit?

We built a .NET 9 API with SQL Server, EF Core and a device management layer for sensors, operators, subjects, recordings and quality control. The API runs on Azure with Key Vault and Managed Identity, uses Keycloak for authentication, TickerQ for scheduled jobs and SendGrid for email. A Flutter app drives the measurement, and a web portal gives clinics and production teams access.

Data in
Device, operator, subject and recording are linked at the moment of measurement, with the raw signal stored against the right record.
Results out
The algorithm service returns a VO₂max estimate, and the API makes it available to the app and the clinic portal.
Evidence
Quality control, production batches and traceability are part of the backend, not a spreadsheet beside it.

Technology

.NET 9
SQL Server
Azure
Keycloak
Flutter

How did the project run?

01Discover
Intended use and constraints
What the device claims, who uses it, and what that means for the software.
02Design
Architecture that traces
Requirements linked to risks and tests from the first sprint.
03Build
Increments you can test
A working backend every two weeks, demoed to the team.
04Launch
Live and maintained
Release, monitoring and support under a clear agreement.

Inside the product

VentriJect app design: New Recording, a searchable list of nearby Seismofit sensors by serial number with battery state — Starting a recording: pick the Seismofit sensor from the list. Design, placeholder data.

What was the result?

The Seismofit System is live and CE-marked. A measurement takes under three minutes, and the backend keeps the device, subject, recording and result connected.

Test time<3minFrom sensor on to VO₂max estimate.

Regulatory statusCECE-marked medical device.

Backend domains9Customer, device, operator, recording, QA and more.