Short answer
The best Horos alternative depends on what outgrew Horos. For a free desktop viewer on Windows or Linux, Weasis is the closest match and passed every transfer syntax in our test. For a free viewer that opens on a Mac without installing anything, the MiniPACS in-browser viewer does that. For a clinic that needs one shared archive, multi-user access, encrypted backups and a worklist, MiniPACS is the self-hosted PACS step up. That last one is a category change, not a like-for-like swap, and the table below is honest about it.
Horos alternatives in 2026: 8 viewers compared
Horos 4.0.1 is free under LGPL 3.0, Mac only, and now builds for Apple Silicon and macOS 26 Tahoe (horosproject.org). Every row below was checked against the vendor's own page or release feed on 28 August 2026. Where a vendor does not state something, the cell says "not published" rather than guessing.
| Platform | License / price | Still maintained? | PACS built in? | Notes |
|---|---|---|---|---|
| Weasis | Free, open source (EPL 2.0 or Apache 2.0) | Yes. v4.7.3 released 25 Aug 2026 | No. Viewer only, connects to an existing PACS | Java desktop app for Windows, macOS and Linux. Passed all nine transfer syntaxes in our test. |
| OsiriX MD | Commercial, from $69.99/mo. FDA cleared, CE II | Yes. Supports macOS 26 Tahoe. Release date not published | Partial. Local SQL database, DICOM send/receive, query/retrieve | The parent of the Horos codebase. macOS only, Intel and Apple Silicon. |
| RadiAnt | Commercial. 1-year plan 39 EUR per PC, CD/DVD license 399 EUR | Yes. 2026.1 released 7 Aug 2026 | No. PACS client (query/retrieve) only | Windows 7 to 11 only. Time-based license stops working after expiry. |
| MicroDicom | Free for non-commercial use. Commercial license US$99, no expiry | Yes. 2026.3 released 10 Jun 2026 | No. PACS client (C-FIND, C-MOVE, DICOMweb) | Windows only (macOS via Wine or CrossOver). 3D MPR and volume rendering since 2026.3. |
| 3D Slicer | Free, open source (BSD-style) | Yes. Stable 5.12.3 built 23 Jul 2026 | No. Research platform with DICOM import and networking | Windows, macOS, Linux. Not approved for clinical use, intended for research. |
| Starviewer | Free, open source (GPLv3) | Site online, downloads offered are 0.14.0-RC1. Last default-branch commit on GitHub: Apr 2023 | Not published | Windows and Linux installers from the University of Girona. Treat as dormant. |
| MiniPACS free in-browser viewer | Free, no signup | Yes. Ships with the MiniPACS site, updated Aug 2026 | No. Standalone page, files never leave your browser | Runs on any modern browser on Mac, Windows or Linux. Decodes all nine transfer syntaxes in our test, including RLE and deflated. |
| MiniPACS (archive with its viewer) | $3,600 per location per year, flat, no per-study fees | Yes. Self-hosted, stable and beta update channels with health-gated rollback | Yes. Self-hosted PACS: archive, worklist, browser viewer, encrypted backups | Browser viewer cold-opens a study in about 0.6 seconds (measured). Archive stays read-only for view, export and share if payment lapses. |
One tested fact matters more than any feature list. In our nine transfer syntax decode test, Horos 4.0.1 rendered RLE Lossless with corrupt pixels (a near-white, speckled image) and showed a flat grey placeholder for the Deflated Explicit VR Little Endian file. Weasis 4.7.3 passed all nine, and so did the MiniPACS in-browser viewer. If a CD from an outside imaging center opens wrong in Horos, that is the first thing to check.
For the wider category beyond this shortlist, see DICOM viewer. Horos is the free fork of OsiriX, so the OsiriX alternative page covers the same lineage from the paid side.
Where Horos is still the better fit
Horos makes sense when the clinic or user wants a Mac desktop viewer. It can be the right tool for local review, outside studies, education, research or a workstation-centered workflow where one Mac is the place studies are opened. In that case, a full PACS may be more system than the job needs, and a Windows-only viewer such as RadiAnt or MicroDicom is no help at all.
The limitation is not a failure of Horos. It is the natural boundary of a desktop viewer. A viewer does not make one durable, shared imaging archive for a clinic. It does not decide access for several users, maintain encrypted backups, keep a worklist, or define what happens to the archive if payment lapses. Those are PACS questions, and that is where MiniPACS enters the comparison.
| Horos DICOM viewer | MiniPACS | |
|---|---|---|
| Category | Free Mac desktop DICOM viewer | Self-hosted PACS with a browser viewer |
| Best fit | One Mac-centered viewing workflow | One clinic archive reached from multiple devices |
| Operating system | Mac desktop application | Browser access from the PACS on any supported OS |
| Archive | Not the central PACS archive | Stores and indexes studies on the clinic's own server |
| Backups | Handled outside the viewer | Encrypted backups are part of the MiniPACS posture |
| Pricing | Free viewer, separate from any archive cost | $300/mo flat per location ($640/mo with the Vendo referral portal), billed yearly, no per-study fees |
Where MiniPACS fits, and where it does not
MiniPACS is for the moment a Mac-only viewer is too narrow for the clinic's workflow. The archive lives on the clinic's own server, users open studies through a browser, and the viewing path does not depend on installing the same desktop viewer everywhere. A Mac user can open the viewer. So can a Windows user with browser access to the same PACS.
MiniPACS does not fit a single user who only wants to open a study from a disc on one Mac. For that job it is more system than the problem needs; use Horos, Weasis or the free in-browser viewer. It also does not replace a diagnostic-grade desktop workstation for 3D post-processing; Horos, OsiriX MD and 3D Slicer keep that ground.
That cross-device access is only half the point. The bigger point is archive control. MiniPACS is self-hosted, licensed flat by location, with no per-study fees, daily AES-256 encrypted backups and read-only access if a payment lapses. In practice that browser viewer cold-opens a study in about 0.6 seconds (measured). If the clinic wants the imaging history on its own server rather than scattered across workstation workflows, the PACS category is the right place to compare. For the broader hosting tradeoff, see cloud PACS vs onsite.
MiniPACS gives a Mac-and-Windows clinic one browser viewer over a shared, backed-up archive on its own server - open the live demo and read a study yourself.
Mac desktop viewer versus browser PACS
The operating system question is practical. Horos is for Mac users who want a Mac desktop viewer. MiniPACS is for mixed or shared environments where the archive is central and the viewer opens in a browser. That means the clinic can standardize the archive without standardizing every workstation around one installed viewer.
If the real search is "horos dicom viewer for mac", the user may simply need a Mac viewer. If the real problem is "our studies need to be in one place and opened by several people", the user needs a PACS conversation. For the viewer category, see DICOM viewer. For how the archive works, see what is PACS.
What to check before switching categories
- Mac-only or shared. If one Mac desktop is the workflow, a Mac viewer can be enough. If several users need the same archive, evaluate PACS.
- Archive location. Decide whether studies should live on a workstation workflow or on the clinic's own server.
- Browser access. Confirm whether users need to open studies from different operating systems without installing a desktop viewer.
- Backups. Ask where the complete archive is backed up and how restores are handled.
- Exit path. Confirm that the archive remains viewable and exportable if the clinic changes vendors or payment lapses.
For PACS vendor questions, see comparing PACS vendors. For PACS software categories, see PACS software. Weighing a specific desktop viewer instead? See the Weasis, MicroDicom and RadiAnt alternative pages. For the live product and pricing, see the landing.
FAQ
What is the best Horos alternative for a clinic?
It depends on the requirement. If the need is still a free Mac desktop DICOM viewer, the closest Horos alternative is another viewer in the OsiriX lineage. If the need has grown into one shared archive on the clinic's own server, multi-user access, encrypted backups, a worklist and a browser viewer that opens on any supported operating system, MiniPACS is the self-hosted PACS step up rather than a like-for-like viewer swap.
Is Horos a PACS?
No. Horos is a free Mac DICOM viewer derived from the OsiriX lineage. It is a desktop viewer for opening and reviewing studies on a Mac. A PACS is the shared archive and delivery system behind viewers. MiniPACS is a self-hosted PACS with a browser viewer included.
Does MiniPACS work for Mac users?
Yes. MiniPACS viewing happens in a browser as part of the PACS, so Mac users can open studies without installing a Mac-only desktop viewer. The same browser-based workflow also works for users on Windows or other supported browsers, because the archive is central.
When should a clinic keep using Horos?
Keep using Horos when the job is local Mac viewing, especially for one user or a workstation-centered workflow. Move to a PACS when the job is central archive, shared access, worklist, backups, export and long-term study ownership.
What does MiniPACS cost?
MiniPACS is licensed flat by location. MiniPACS alone is $3,600 per location per year, and MiniPACS plus Vendo is $7,680 per location per year. There are no per-study fees, and if payment lapses, the archive remains read-only for view, export and share.
