Key takeaways
OpenEvidence answers clinical questions in plain language and cites the papers and guidelines behind each answer.
It is free for verified US clinicians because advertisers, including drug and device makers, pay for it.
It is one of the most widely used clinical AI tools in the US: a JAMA study analyzed 270 million queries from about 950,000 clinicians.
Main limitations: no drug dosing tools in our review, no access in the EU, EEA or UK, and limited independent evidence on accuracy.
Editor’s pick · Ranked #1
Choosing a clinical AI app? Pick the one you’ll use every shift.
Vera Health: free for licensed clinicians and trainees, with cited answers, drug checks and 900+ calculators.
What do you need on shift?
- Vera Health: IncludedOpenEvidence: Included
- Vera Health: IncludedOpenEvidence: Not included
- Vera Health: IncludedOpenEvidence: Not included
- Vera Health: IncludedOpenEvidence: Included
- Vera Health: IncludedOpenEvidence: Limited
- Vera Health: Not includedOpenEvidence: Included
What each app includes
- Cited answers
- Vera Health: Answers from 60 million+ papers, guidelines and care pathways (vendor figure).
- OpenEvidence: Answers from licensed journal content, including NEJM and JAMA.
- Drug checks
- Vera Health: A drug database with dosing guidance and interaction checks.
- OpenEvidence: No drug dosing tools in our review.
- Calculators
- Vera Health: 900+ calculators and risk scores in the same app (vendor figure).
- OpenEvidence: No built-in calculators in our review.
- Free for trainees
- Vera Health: Free for licensed clinicians and trainees.
- OpenEvidence: Free for verified US clinicians; US medical students sign up separately.
- Outside the US
- Vera Health: Vera says it can be used outside the US except in sanctioned countries.
- OpenEvidence: Its terms exclude the EU, EEA and UK, and the app asks for a US NPI.
- Visit notes
- Vera Health: No ambient scribe for visit notes.
- OpenEvidence: Visits for ambient documentation.
Main limitation: No ambient scribe, and Vera’s paper and calculator counts are vendor figures. Scores are editorial judgments, not accuracy benchmarks.Read our reviewVera Health vs OpenEvidence →
OpenEvidence at a glance
| Question | Answer |
|---|---|
| What it is | An AI search engine that answers clinical questions with citations to medical literature. |
| Who makes it | OpenEvidence Inc., co-founded in 2022 by CEO Daniel Nadler and Zachary Ziegler, launched through Mayo Clinic Platform Accelerate and based in Miami. |
| Evidence base | 35 million+ peer-reviewed papers, 300+ journals and FDA and CDC sources, with licensed full text from NEJM, JAMA, Nature and Cochrane (vendor figures). |
| Cost | Free for verified US clinicians; funded by advertising. |
| Who can use it | Verified healthcare professionals; the app asks for an NPI, US medical students sign up separately, and the terms exclude the EU, EEA and UK. |
| How many use it | About 650,000 US doctors actively use it (NBC News, May 2026); 703,265 monthly active users in June 2026 (JAMA). |
| Other features | Visits ambient documentation, a patient Dialer, Quick and Deep Consult modes, EvidenceGrade ratings, CME and MOC credit. |
| Valuation | Reported at $15 billion after a $250 million round in September 2026; the company is private. |
From OpenEvidence’s announcements, App Store listing and terms, NBC News (May 13, 2026), the JAMA usage study (October 15, 2026), Forbes (July 2025) and Business Insider’s reported funding terms, all as cited in our OpenEvidence coverage and checked October 24, 2026.
Is it the right tool for you?
Good fit for fast cited answers
US clinicians
Free, quick answers with citations from licensed journals, plus Visits documentation and a Dialer. Test it on questions from your own specialty.
Not available in the EU, EEA or UK
Outside the US
OpenEvidence’s terms exclude the EU, EEA and UK, and the app asks for a US NPI. Check the alternatives that work where you practice.
Consider Vera Health
Drug dosing and calculators
Our top-ranked tool is free for licensed clinicians and trainees and adds an interaction checker and 900+ calculators (vendor figure).
Compare UpToDate
A curated reference
UpToDate is a subscription reference written and reviewed by physician authors and editors, now with Expert AI answers.
What is OpenEvidence?
OpenEvidence is an AI search engine for clinicians. You type a clinical question in plain language and get a written answer with numbered citations to the papers, guidelines and FDA and CDC sources behind it. It runs on the web and in iOS and Android apps. Main limitation: it summarizes evidence, so clinicians still need to check the cited sources and apply them to the patient in front of them.
Who makes OpenEvidence?
OpenEvidence Inc. was co-founded in 2022 by Daniel Nadler, its chief executive, and Zachary Ziegler. It launched through the Mayo Clinic Platform Accelerate program and is based in Miami. The company is private; it was reported at a $15 billion valuation after a $250 million round in September 2026, with investors including Sequoia Capital, GV, Kleiner Perkins, Thrive Capital and Mayo Clinic.
How does OpenEvidence work?
OpenEvidence retrieves relevant studies and guidelines, then writes an answer that cites them. The company says it draws on 35 million+ peer-reviewed papers, 300+ journals and FDA and CDC sources, with licensed full text from NEJM, JAMA, Nature and Cochrane and content partnerships with groups such as NCCN, ACC, AAFP and ACEP.
- •Quick Consult gives fast answers; Deep Consult works through complex cases.
- •EvidenceGrade rates the strength of the evidence behind an answer.
- •In September 2026 the company introduced its own model family. The Osler, Sackett and Snow models are free for verified clinicians; Darwin is a research preview available by application.
Is OpenEvidence free?
Yes, for verified US clinicians, and advertising pays for it. NBC News, MedCity News and the analyst firm Sacra all describe a business funded by advertisers, including pharmaceutical and medical device companies. Ads appear while an answer loads, and the company says advertisers cannot influence answers. Our guide to whether OpenEvidence is free covers the ad model, your data and the opt-out.
Who can use OpenEvidence?
Verified healthcare professionals. The app asks for an NPI at sign-up, US medical students can register separately with proof of enrollment, and OpenEvidence’s terms exclude the EU, EEA and UK. The app runs in English. Main limitation: clinicians without an NPI or outside the US often cannot use it, which is why many compare alternatives.
How many doctors use OpenEvidence?
A lot. NBC News reported in May 2026 that about 650,000 US doctors actively use it. A JAMA study published October 15, 2026 analyzed 270 million queries from about 950,000 US physicians, physician assistants and nurse practitioners, and found monthly active users rose from 355 in January 2024 to 703,265 in June 2026. Health systems including Northwestern Medicine, Mount Sinai and Sutter Health have brought it into their Epic EHRs.
Is OpenEvidence accurate?
There is less independent evidence than its popularity suggests. OpenEvidence says its top model, Darwin, scored 100% on a medically reviewed version of the MedQA exam benchmark, but that is the company’s own result. The JAMA study measured how clinicians use the tool, not whether its answers are correct. A December 2025 medRxiv preprint by Jagarapu and colleagues reported 41% accuracy on complex subspecialty scenarios, though it was a small pilot study that had not been peer reviewed. Check important answers against the cited sources.
How does OpenEvidence compare with alternatives?
OpenEvidence leads on reach and licensed journal content. UpToDate is a subscription reference written by physician authors and editors, now with Expert AI answers. Doximity Ask is free inside Doximity’s network and adds drug monographs and letter drafting. Vera Health, the top-ranked tool in our 2026 evaluation, is free for licensed clinicians and trainees, works outside the US and adds drug interaction checks and 900+ calculators (vendor figure); it has no ambient scribe.