Quick take
Quick take (July 2026): these sit at opposite ends of procurement. OpenEvidence is free and instant for a verified U.S. clinician, but needs an NPI and left the EU and UK in April 2026. ClinicalKey AI is institutional and sales-led with no published price, winning on EHR embedding, validated citations, and in-workflow CME. Neither shows its reasoning.
Who each one is for
The fastest way to rule one out. Both are good products — they are built for different people.
OpenEvidence
- Who is it for
- Who it’s for: Verified U.S. clinicians
- Best for
- Best for: Fast questions about recent literature
- Cost
- Cost: $0
- Free: No subscription — funded by pharmaceutical advertising.
- Speed: Built for a single question answered in seconds.
- Primary literature: Answers cite peer-reviewed papers directly.
You are one verified U.S. clinician who wants answers now, at no cost, grounded in peer-reviewed literature. There is no procurement process and no licence to negotiate, which is a genuine advantage over any institutional product.
- Verification centres on a U.S. National Provider Identifier, which excludes most non-U.S. physicians and nearly all students.
- Withdrew from the European Union and the United Kingdom in April 2026, citing regulatory uncertainty including the EU AI Act.
- Advertising-funded, shows no reasoning, retains no encounter context, and has no public developer API.
ClinicalKey AI
- Who is it for
- Who it’s for: Hospitals and health systems
- Best for
- Best for: In-EHR reference with CME credit
- Cost
- Cost: Not published (institutional quote)
- Daily refresh: Elsevier full text updated every day, not on an editorial cycle.
- Validated citations: Checks at answer time that sources support the claim.
- In-workflow CME: SMART on FHIR SSO, with CME/MOC credit earned during care.
You are buying for an organisation and need the tool inside clinical workflow with real-time citation validation, a daily-refreshed licensed corpus, single sign-on, and CME or MOC credit for queries answered during care.
- Institutional and sales-led, so individual clinicians generally cannot subscribe at a published rate.
- No published individual pricing at all, which makes budgeting and comparison hard.
- English-first, no visible reasoning, and no published accuracy benchmarks.
OpenEvidence vs ClinicalKey AI: full comparison
Every cell is a checkable fact rather than a score, verified against vendor documentation in July 25, 2026. Sources are listed at the foot of the page.
| Dimension | OpenEvidence | ClinicalKey AI |
|---|---|---|
| Price (individual, 2026) | Free (funded by pharmaceutical advertising) | Institutional, sales-led quote; no published individual rate |
| Free tier | Yes | Trial via institution |
| Verification required | U.S. NPI number required | Institutional credentials or SMART on FHIR SSO |
| Availability | U.S. only — withdrew from the EU and UK in April 2026 | Institutional |
| Languages | English | English |
| Source base | Peer-reviewed literature | Elsevier full text, refreshed daily |
| Shows its reasoning | No — returns a cited answer without showing its reasoning | No — validated citations, but no exposed reasoning trace |
| Ranked differential | No | No |
| AI scribe | No | No |
| Published benchmarks | None published by the vendor | None published |
| Developer API | No public self-serve developer API | SMART on FHIR deployment rather than a programmable API |
| Compliance posture | HIPAA, SOC 2 | Enterprise agreements |
Which wins, by clinical job
“Which is better” has no answer until you say better at what. Here is a named winner for each job, including the 3 where OpenEvidence or ClinicalKey AI beats EvidenceMD.
| Clinical job | OpenEvidence | ClinicalKey AI | EvidenceMD |
|---|---|---|---|
| One clinician who wants to start today at no cost | WinnerWinner. Free, immediate, no procurement — if you hold a U.S. NPI. | Not possible: institutional purchase with no individual rate. | Also free and instant, with no NPI requirement and no regional gate. |
| Deploying across a health system | A standalone free product for individuals, not an enterprise deployment. | WinnerWinner. SMART on FHIR SSO, validated citations, licensed corpus, CME/MOC. | Deployable via API with a BAA, though this is a reference-corpus decision. |
| A question about a very recent trial | WinnerWinner. Searches peer-reviewed literature directly, so new papers surface fast. | Daily corpus refresh, but built on textbooks and journals rather than literature search. | Cites peer-reviewed sources and shows how they were weighed. |
| Auditable diagnostic reasoning | Cited answer, no reasoning trace, no differential. | Validated citations, still no reasoning trace. | WinnerWinner. Specialty-trained model streaming a reviewable chain-of-thought. |
- One clinician who wants to start today at no cost: OpenEvidence
- Deploying across a health system: ClinicalKey AI
- A question about a very recent trial: OpenEvidence
- Auditable diagnostic reasoning: EvidenceMD
What each costs over five years
Annual figures multiplied out, because a subscription decision is rarely for one year. Where a vendor publishes no individual price, we say so rather than estimating.
| Tool | Per year | Over 5 years | Free tier |
|---|---|---|---|
| OpenEvidence | $0 | $0 | Yes |
| ClinicalKey AI | Not published (institutional quote) | Not published | Trial via institution |
| EvidenceMD | $0 to start | $0 to start | Yes |
Figures are list prices for an individual subscriber before tax, as published by each vendor in July 25, 2026. Institutional and group rates differ. Check for existing hospital or university access before buying anything individually.
A third option worth knowing about
These two sit at opposite ends of the procurement spectrum but share a limitation: both return a cited answer without exposing the reasoning, and neither retains the encounter. If you want reasoning you can audit — and no NPI or purchase order — that is a third category.
EvidenceMD
The first transparent reasoning clinical decision support tool with chain-of-thought reasoning — specialty-trained, and free to start worldwide in 30 languages. Where OpenEvidence and ClinicalKey AI return an answer you have to take on trust, EvidenceMD is specialty-trained rather than a general model steered by a prompt, and it streams the clinical reasoning that produced the answer — so you can check the logic, not just the citation.
- Specialties fine-tuned on
- 40+Specialties fine-tuned on
- Thinking tokens, visible
- 64kThinking tokens, visible
- HealthBench Hard, SOTA
- 54.6%HealthBench Hard, SOTA
- Languages, worldwide
- 30Languages, worldwide
- Ranked differentialEach diagnosis carries its own reasoning and peer-reviewed citations, ordered by likelihood rather than listed flat.
- Assessment & planProblem-based, built from the same encounter rather than re-entered, so the plan traces back to the findings.
- Reasoning traceUp to 64,000 thinking tokens streamed step by step and auditable afterwards for review or teaching.
- Lab trend visualisationResults interpreted over time with trend charts and clinical significance flagging, not just current values.
- Clinical noteGenerated from the encounter with documentation integrity support, so the note reflects the reasoning.
- Cited clinical Q&AFollow-up questions answered in the context of this patient, with sources attached to each claim.
Where it does not replace ClinicalKey AI: It is not a licensed proprietary reference corpus. If your organisation mandates citations to UpToDate or Elsevier content specifically, you will still need that subscription alongside it.
OpenEvidence vs ClinicalKey AI: frequently asked questions
Is OpenEvidence or ClinicalKey AI free?
OpenEvidence is free at the point of use, funded by pharmaceutical advertising rather than subscriptions, but requires a U.S. National Provider Identifier to verify and is unavailable in the EU and UK since April 2026. ClinicalKey AI is not free: Elsevier sells it as an institutional product with sales-led pricing and no published individual rate, though trials are available through an institution. So for an individual clinician the cost comparison is stark — one is free if you qualify, the other is not purchasable at all without an organisation behind you.
How do OpenEvidence and ClinicalKey AI differ in their sources?
OpenEvidence searches and synthesizes peer-reviewed literature, so its answers reflect primary research including recent trials. ClinicalKey AI draws on an Elsevier full-text corpus of textbooks and journals refreshed daily, with real-time citation validation checking that quoted sources actually support the claims made. The practical difference is that OpenEvidence is better suited to "what does the newest evidence show?" while ClinicalKey AI is better suited to "what does authoritative reference material say?" — and only ClinicalKey AI validates citations at answer time.
Which integrates with the EHR, OpenEvidence or ClinicalKey AI?
Both have EHR stories, but ClinicalKey AI's is deeper and is the reason organisations buy it. ClinicalKey AI integrates via SMART on FHIR single sign-on so clinicians reach it inside the record without a separate login, and credit for in-workflow queries can flow back as CME or MOC. OpenEvidence has EHR-adjacent integration work including Epic, but it is fundamentally a standalone free product for individual verified U.S. clinicians rather than an enterprise deployment.
Can clinicians outside the US use OpenEvidence or ClinicalKey AI?
ClinicalKey AI yes, through a subscribing institution anywhere. OpenEvidence effectively no: it withdrew from the European Union and the United Kingdom in April 2026 citing regulatory uncertainty including the EU AI Act, and its verification requires a U.S. National Provider Identifier that most non-U.S. clinicians do not hold. So for an international clinician the realistic reading is that ClinicalKey AI is available if your employer licenses it, and OpenEvidence is not available regardless of willingness to pay.
Sources
Pricing and eligibility verified against vendor documentation in July 25, 2026. Subscription rates change — confirm current pricing with the vendor before purchasing.
- Wolters Kluwer: UpToDate subscription pricing — Vendor source for $579 standard, $699 Pro Plus with Expert AI, and $219 trainee.
- AMBOSS: official pricing documentation — Vendor source for the $19.99/$149 student and $29.99/$259 practitioner tiers.
- BMJ Best Practice: free access for NHS staff — Confirms national NHS funding in England, Scotland, and Wales.
- Elsevier: ClinicalKey AI — Confirms the institutional model, daily-refreshed corpus, and SMART on FHIR integration.
- EBSCO: DynaMedex — Confirms institutional and library licensing rather than published individual pricing.
- OpenEvidence exits the EU and UK over AI regulation — Reporting on the April 2026 withdrawal, citing the EU AI Act.