What Horos Project does

Horos Project is an open-source initiative that develops and distributes Horos, a free DICOM (Digital Imaging and Communications in Medicine) medical image viewer exclusively for macOS. Built on community-contributed code under the GNU Lesser General Public License Version 3.0, the product supports viewing and analysis of MRIs, CTs, X-rays, PETs, and ultrasounds, with advanced visualization features including 3D multi-planar reconstruction, volume rendering, surface rendering, SUV measurement, and 3D MIP imaging. The project is operated as a community-led initiative sponsored by Purview, which has shouldered technical maintenance and financial obligations for more than 6.5 years, with Les Trachtman serving in a technical-author and compliance role. Users span 160+ countries across all seven continents and include individual specialists (radiologists, neurosurgeons, orthopedic surgeons, physiotherapists), veterinarians, medical educators, students, legal/forensic experts, and a small number of institutional accounts such as Treviso Hospital in Italy and IT integrator Synergy in Chile. As of the most recent release, Horos 4.0.1 supports Apple Silicon and macOS 26 Tahoe and integrates the HorosCloud Plugin for cloud connectivity.

The business model is freemium at its core: the desktop viewer is distributed at zero cost with no advertising, and revenue is generated through a small set of optional paid services routed through Purview and other partners. Monetization streams include voluntary community donations (a ~$100,000 annual goal supported by roughly 1,000 of ~500,000 users), Horos Cloud Access subscription (cloud PACS storage starting at $60/month), Horos Cloud Reporting subscription ($1.99/month, targeted at the veterinary segment), Horos Academy training courses (multi-language, sold with coupon discounts), and quote-based professional technical support from Purview. Distribution is primarily self-serve via direct download from horosproject.org, with paid cloud and reporting tiers sold through horoscloud.io. The go-to-market is community-led and product-led: user spotlights, blog content, webinars co-hosted with Purview, GitHub contributions, and community events drive organic adoption, while FDA and CE regulatory clearances are pursued to expand use into regulated clinical settings. The company has no disclosed revenue figures, a volunteer-driven headcount supplemented by Purview, and Minnies 2018 finalist recognition as its principal industry award.

Name

Horos Project

Legal name

Horos Project

Website

https://horosproject.org

Company type

Private

Founded year

2015

Operating status

Operating

Short description

Horos Project distributes a free, open-source DICOM medical image viewer for macOS, used by approximately 500,000 clinicians, veterinarians, educators, and legal experts across 160+ countries, with revenue generated through optional cloud, reporting, training, and support services.

Ownership category

akta.pro rank

Product category

Medical Imaging Software

NAICS

Software Publishers (5132), Software Publishers (51321), Computer Systems Design and Related Services (54151)

SIC

Surgical & Medical Instruments & Apparatus (3841), Services-Computer Programming Services (7371)

akta.pro primary industry

Universal Viewers & Enterprise Imaging Access (Zero-footprint/Diagnostic) (HLACALAD)

akta.pro secondary industries

Imaging & Diagnostic Interoperability (DICOM exchange, image sharing, VNA connectivity) (HLACABAM), Image Exchange, Sharing & Patient/Provider Portals (DICOM/Web) (HLACALAI), Imaging/Lab Integration & Results Management (PACS, LIS Connectivity, Reporting) (HLAMAGAK)

Keywords

• Medical image viewer
• DICOM viewer software
• Open source healthcare
• Radiology imaging tools
• Medical imaging platform

Headquarters

HQ city

Brooklyn

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2C

Offering type

Software

Cost components

Technology or R&D, Personnel, Infrastructure, Marketing or Sales, Operations

Revenue model

1. Software Distribution (Free): Horos is distributed free of charge as open-source software. This drives massive user adoption and community growth, creating a large potential customer base for paid add-on services.
2. Donations: Voluntary donations from community members. Approximately 1,000 of ~500,000 users contribute. Goal is to raise ~$100,000 annually to fund part-time technical resources.
3. Horos Cloud Access: Cloud-based PACS storage service starting at $60/month. Provides secure archive, disaster recovery, and multi-location access for medical images.
4. Horos Cloud Reporting: Cloud-based reporting subscription at $1.99/month (veterinary). Enables in-app report creation with branding and sharing capabilities.
5. Professional Support Services: Paid technical support services offered by Purview for Horos users who need assistance.
6. Training Materials: Horos Academy offers training videos and user documentation for purchase.

Pricing tiers

Go-to-market motion2 records

Distribution channels5 records

Marketing channels9 records

Core offering

Horos Project distributes a free, open-source DICOM (Digital Imaging and Communications in Medicine) medical image viewer for macOS, allowing clinicians, veterinarians, researchers, and students to view, analyze, and report on MRIs, CTs, X-rays, PET scans, and ultrasounds with advanced 3D visualization. The project supplements the free viewer with optional paid services including Horos Cloud Access (cloud PACS storage starting at $60/month), Horos Cloud Reporting (subscription-based reporting at $1.99/month), Horos Academy training courses, and professional technical support delivered by sponsor Purview.

Product overview

Horos Project offers a suite of free and open-source medical imaging solutions centered on its core product, the Horos DICOM Viewer for macOS. The product portfolio includes Horos Cloud for cloud-based storage and sharing, Horos Cloud Reporting for integrated report creation, Horos Access for archive-only cloud functionality, Horos Academy for training, and professional support services. The ecosystem allows users to view, store, share, and report on medical images across multiple platforms and locations while maintaining DICOM compliance.

Differentiator

Problem solved

Functional benefit

Brands

• Horos Academy: Horos training platform offering video modules and courses for learning the software, available in English, Portuguese, and Spanish.
• Horos Cloud
• Horos Cloud Access

Products and services

• Horos (Free DICOM Viewer) Free, open-source DICOM medical image viewer for macOS that allows clinicians, veterinarians, researchers, and students to view and analyze medical images including MRIs, CTs, X-rays, PETs, and ultrasounds. Supports 3D MPR, volume rendering, surface rendering, and multiplanar reconstruction with no advertisements and offline operation.
• Horos Cloud Cloud-based storage and sharing platform that integrates with the Horos desktop viewer, providing secure, compliant medical image storage with web-based access to studies from anywhere on any device.
• Horos Cloud Reporting Integrated reporting plugin enabling creation of templates and professional branded reports within Horos at $1.99/month. Reports can be saved as PDFs or DICOM files alongside associated studies, with key image capabilities and customizable templates with logos.
• Horos Access Archive-only cloud account starting at $60/month for use with desktop viewers like Horos. Allows connection of multiple Horos workstations, compatible with OsiriX and Windows-based viewers, providing an inexpensive entry point into cloud-based medical image archives.
• Horos Academy Paid training platform offering video-based courses for Horos users with comprehensive user guides and tutorials available in English, Portuguese, and Spanish. Covers basics through advanced features in structured modules with discounts available for educators and classrooms.
• Horos Technical Support Professional personalized technical support services offered by Purview, the chief sponsor of Horos, providing dedicated assistance to help users maximize their use of Horos with quote-based pricing.

Quantifiable outcome

• Horos Cloud Reporting enabled Dr. David Priest to eliminate separate text editor workflow, save templates within the platform, and create professional reports that serve as marketing tools for his equine veterinary practice.
• +2 more outcomes

Named customers14 records

Segments5 records

Ideal customer profiles5 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration2 records

Feature8 records

Partnerships

Three partnerships are on record, tiered minor and core.

• AppleminorStrategic or Co-development Partner · 1 January 2018Apple hosted the Horos Project during RSNA 2018, providing a board room venue for Horos users from around the world to participate in the event. Horos is exclusively developed for macOS and Apple platforms.
• GitHub Open Source CommunitycoreStrategic or Co-development PartnerHoros encourages community members to modify and improve the code through GitHub. Experts around the world develop features and functions, with most routing code back to the Horos Project for validation and incorporation into the most current version.
• Horos Academy PartnersminorGTM or Marketing PartnerTraining content partnerships providing courses in English, Portuguese, and Spanish for Horos users worldwide. Discounts available for educators and classrooms.

Scale indicators8 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• MicroDicom: Free DICOM viewer for Windows used by clinicians and students for primary diagnostic reading and image review. Direct competitor to Horos in the free, individual-practitioner DICOM viewing segment, differing by platform but addressing the same price-sensitive user base.
• 3D Slicer: Free, open-source platform for medical image visualization, segmentation, and analysis maintained by a global research community. Competes with Horos in academic and research radiology use cases, offering similarly free advanced visualization capabilities with broader segmentation and research toolkits.
• RadiAnt (Medixant): Commercial DICOM viewer (Windows) widely used by individual radiologists and specialists for its speed and simplicity. Competes with Horos for the same individual practitioner DICOM-viewing use case, differentiated by platform (Windows vs. macOS) and pricing model (paid license vs. free).
• OsiriX (Pixmeo): The original open-source DICOM viewer for macOS from which Horos was forked when OsiriX moved to a commercial model. Targets the same radiologists and medical specialists with a comparable feature set including 3D MPR and advanced visualization, now as a paid product.

Broad incumbents

• Philips IntelliSpace Portal: Enterprise clinical visualization and quantification platform from Philips, broadly serving radiology departments with advanced visualization, AI, and reporting workflows. Represents the large incumbent PACS/visualization tier Horos cannot credibly challenge today but may aspire to expand into post-regulatory clearance.
• Carestream Vue PACS: Enterprise PACS and imaging workflow platform from Carestream used by hospital systems globally. Broad incumbent alternative that competes for the same radiology imaging workflow budget pools, though focused on large enterprise deployments rather than individual practitioners.
• Purview: Chief sponsor and operational curator of Horos Project, also offering Purview Lite/Image as a broader cross-platform medical imaging platform (Windows + cloud). Peer as a competing/adjacent medical imaging viewer platform with overlapping customer base, particularly targeting Windows-side enterprise users that Horos cannot serve.
• GE Healthcare Centricity PACS: Enterprise imaging and PACS solution from GE Healthcare serving large hospital and imaging center networks. Overlaps with Horos in the diagnostic imaging viewing category but operates at radically different scale and price point, representing the traditional incumbent Horos contrasts itself against.

Emerging players

• Orthanc: Open-source, lightweight DICOM server and PACS for hospitals and research labs. Adjacent to Horos - rather than a viewer, it is the storage/infrastructure layer that Horos desktop clients connect to (e.g. DCM4CHEE integrations) - positioning Orthanc as a complementary peer in the open-source medical imaging ecosystem.
• Navegatium: DICOM viewer for educational use and clinical review, historically Mac-focused. Adjacent/competing niche peer in the macOS-native DICOM viewer segment with a focus on teaching file use cases for medical students and residents - an overlapping community with Horos.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• GitHubgithub.com/horosproject/horos
• Xx.com/horosproject

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Subsidiaries2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Horos Project