Senior Full Stack Engineer

About Sonari

Sonari is a well-funded startup and the world's first company to deploy AI-powered ultrasound in professional sports, converting a fast, portable scan into objective data on an athlete's tissue health, performance and endurance over time. We're working toward an unprecedented goal: predicting soft-tissue and non-contact injuries.

Our technology is grounded in peer-reviewed research. We're backed by a global investment firm ($70B+ AUM), and we're already in partnership with a Major League Baseball team and a Premier League club. Our aim is to put this capability in the hands of every sports organization in the world, from championship rosters to the academies where the next generation is coming up.

We're mission-driven and looking for like-minded top engineers who want to build at the intersection of AI, medical imaging and sports.

The role

You own the platform end to end — the backend API and data model and the web frontend that clinicians and team staff use. The platform is the hub: it authenticates devices and users, ingests the ultrasound the tablet app uploads, stores it in a multi-tenant, de-identified data store, dispatches analysis jobs, and gives clinicians and team staff a web application to review images, add annotations, and track athlete metrics over time. If the app is the point of capture and the models are the intelligence, the platform is where it all lands and becomes useful. Much of the stack is still being decided, so you'll help choose it. You'll work in a fast-paced, hands-on environment, reporting directly to the CTO.

Stack note: we've settled on Django / Django REST Framework for the backend. Most other choices — cloud provider, database, frontend framework, auth provider, image viewer — are not locked in. The role is described tech-agnostically on purpose; strong opinions and the willingness to help make these calls are a plus.What you'll work onBackend

• Greenfield backend in Django + DRF (our chosen framework), backed by a relational database and cloud object storage. A batteries-included stack for a multi-tenant athlete-data app: ORM, migrations, admin, auth.
• Multi-tenancy with strict isolation. Tenant (org/team) is part of every key. Enforce isolation defense-in-depth: row-level isolation and service-layer ownership checks. Strict cross-team isolation is a top requirement.
• Ingest. Implement the device upload contract — an upload-intent step that mints presigned upload URLs and a complete step that verifies the objects landed — including clip and sampling-stream routing.
• Auth. Validate tokens from a managed auth provider (whichever we adopt — the provider may change over time) in the backend, for both web users (team / clinician / admin roles, invite-only, MFA for sensitive data) and the device upload path.
• The annotation & analysis layer. Persist the platform's canonical annotation / measurement / report records; expose the read API for the frontend; dispatch analysis jobs to the ML services and ingest their results (metrics + annotation overlays); fire "new images/results" alerts to staff (event-driven).
• Privacy-ready seams from day one. A separate identifier store keyed server-side, a single audit chokepoint, org-keying everywhere, encryption/TLS throughout — built now so turning on stricter privacy controls later is configuration and paperwork, not a rewrite. Export de-identified images + labels to the model factory.

Frontend

• Build the web frontend from the ground up. The framework and layout are still open — it may be a single-page app or a multi-page app — so you'll help decide the front-end architecture and information design, not just implement a fixed spec: roster and player management, player profiles, longitudinal analytics and trend charts, and a Team Command Center dashboard.
• Front-end UX/UI. The layout and look-and-feel are greenfield; you'll shape them (with design input) so clinicians and team staff can move quickly through review and reporting.
• Embed a web-based medical image viewer (e.g. OHIF / Cornerstone3D, or another) for reviewing ultrasound and adding annotations and measurements, with DICOM interop (DICOMweb, PNG↔DICOM conversion).
• Org-admin and super-admin provisioning/settings UIs.

Required skills

• Strong Python and Django + Django REST Framework (models, migrations, DRF serializers/views, auth).
• Relational database depth (e.g. PostgreSQL): schema design, query performance, and ideally row-level isolation and JSONB/array usage for a multi-tenant app.
• A modern web frontend framework (React, Vue, Svelte, or similar) with TypeScript — building real data-dense UIs (tables, forms, dashboards, charts), plus the judgment to shape UX where the design is greenfield.
• Cloud infrastructure on a major provider: object storage, a managed database, a managed auth provider, secrets management; comfort owning your own infrastructure early.
• Contract-driven development: building against OpenAPI / JSON-Schema definitions and generated types, with additive-only, versioned API discipline.
• A security mindset: multi-tenant isolation, least privilege, auth token handling, and keeping identifying data out of logs and objects.
• AI-assisted development as a daily habit: you use tools like Claude Code, Codex or Cursor to move faster, and you have the judgment to know when their output is right and when it isn't.

Nice to have

• DICOM / PACS / medical imaging on the web — e.g. OHIF, Cornerstone3D, DICOMweb, DICOM SR/SEG.
• Infrastructure-as-code and CI/CD (this role initially stretches to cover DevOps; a dedicated DevOps hire is planned).
• Experience handling sensitive health data and awareness of privacy/regulatory architecture (audit logging, field encryption) — depth is a plus; we retain regulatory specialists separately.
• Event-driven / queue-based backends (job dispatch, alerting).
• Data visualization for longitudinal / time-series metrics, and general product/UX sensibility.

Tech stack you'll touch

Python · Django + DRF (chosen) · a relational database (e.g. PostgreSQL) · a major cloud provider (object storage, managed DB, managed auth, secrets) · a modern web frontend framework + TypeScript · OpenAPI / JSON-Schema contracts · a web-based medical image viewer (e.g. OHIF / Cornerstone3D) + DICOMweb · presigned-upload API · event-driven alerting. (Backend framework aside, most of this is still open.)

How this role fits the team

You'll be one of the first members of our engineering team, and the platform is the connective tissue between the other two roles. You consume the iOS Engineer's uploads and define the API they build against; you dispatch jobs to and display results from the Machine Learning Engineer's analysis services, and feed their model factory with labeled, de-identified data. Every seam is a shared, versioned contract, so the parts of the system move independently without breaking each other.

Pay: $150,000.00 - $200,000.00 per year

Benefits:

• Dental insurance
• Health insurance

Work Location: Hybrid remote in Cambridge, MA 02142