Markus
Welby Health · Clinical AI
A clinical AI teammate for Welby Health nurses. It reads live patient data, reasons out loud, and answers with values you can trust. It shows its work, so a busy shift can lean on it.
Built by Rey Columna. I designed and built Markus and wrote most of the code. A few Welby engineers contributed to the backend. A Welby Health product.
Visit markus.getwelby.com- Built by
- Rey Columna (lead and main author)
- Status
- Live
- Company
- Welby Health
- My role
- Designer and lead builder; CTO, Welby Health
- Type
- Clinical AI assistant
- Site
- markus.getwelby.com
What it is
Markus is not a chatbot. Ask in plain language and it pulls the real record, shows each step it takes, and grounds every number in the data. Bigger jobs keep running in the background while the nurse moves on.
In clinical work, a confident wrong answer is worse than none. Markus is built to refuse the guess: clinical values are checked against the tool results it actually fetched, and missing data is reported, never fabricated.
What it does
Live patient data
Vitals, medications, diagnoses, allergies, devices, and care history, across 30+ clinical tools, on request.
Shows its work
A live checklist of what it is doing, and every clinical value traced back to the record. An honest gap, never a guess.
Works in the background
Hand off a full report or a clinic-wide pull. Markus runs it while you keep working and delivers the result into the chat.
Remembers the thread
Keeps working notes across a review and recalls your preferences between conversations.
Scoped to your panel
Nurses see their patients. Team-wide views are a lead-nurse capability. Privacy is built into every query.
Voice, hands-free
Dictate a question and have Markus read the answer back, for when the cart is moving.
The toolbox
Markus chooses the tools a question needs, so nobody picks from a menu. A sample of what it can reach:
- Patient record: demographics, vitals, medications, diagnoses, allergies, contacts, devices, care summary.
- Population and trends: BP trend analysis, graduation eligibility, communication frequency, clinic patient list, custom analytics.
- Documents and reports: full clinical reports, protocol compliance (SBAR), charts, Google Docs and Sheets.
- Workflow: background tasks, working notes, memory recall, voice in and out, hardware and supply orders.
Built to be trusted
Verified, not invented. Values are checked against the tools Markus actually called.
Role-aware access. Every patient query is scoped to who is asking: nurses to their panel, leads to their team.
Fast, cost-efficient reasoning over full clinical context, with prompt caching.
All details above are from the public Markus site.
What I personally did
I designed and built Markus: the product design, the architecture, the backend, the web app, and the day-to-day running of it. It is Welby Health's product, and I'm the CTO there. The code is company-owned and private, so I can't link it. The repository history shows this:
- Frontend: 171 of 171 commits on the main branch are mine.
- Backend: 242 of 303 commits on the main branch are mine. A few Welby engineers wrote the rest.
- Latest commit on the main branch: October 27, 2026.
- About 55,000 lines of backend code and about 21,000 lines of frontend code, with about 100 test files.
I'm happy to walk through it live, so email me. I've also written about how it works: