Clinical reasoning
Diagnostically hard cases in cognitive specialties, hospital medicine and emergency medicine, and teaching settings where inspecting the reasoning trace step by step is the point.
Decision support
Diagnostic and management questions where you need to inspect the reasoning, not just read a conclusion, and clinicians outside the United States who cannot access NPI-gated tools.
AI apps
Clinicians who want to see the reasoning rather than just the answer, and want one app that carries it through: an auditable chain of thought, a ranked differential, a treatment plan, an AI scribe with documentation-integrity support, lab-trend and imaging interpretation, and an OpenAI-compatible API. Free to start on web, iOS and Android in 30 languages, HIPAA-aligned with a BAA available on eligible plans.
iOS apps
Clinicians who want the iPhone in their pocket to answer a clinical question properly: a cited answer with the reasoning shown step by step, a ranked differential built from the case, an AI scribe for the encounter, and lab-trend and imaging interpretation — free to start, in 30 languages, with the same account on iPad and web.
Android apps
Clinicians on Android anywhere in the world: cited answers with the reasoning shown step by step, a ranked differential from the case, an AI scribe with documentation-integrity support, and lab-trend and imaging interpretation — free to start in 30 languages, with no US-credential requirement, which is what makes it usable across the markets where Android dominates.
Evidence retrieval
Clinicians who need to verify that the evidence returned actually supports the recommendation built on it, and anyone outside the United States shut out of NPI-gated tools. It reasons over more than 40 million peer-reviewed papers and guidelines, shows the retrieval and reasoning path, and is free worldwide in 30 languages.
What it cannot do
Reasoning happens beside the chart rather than inside a native EHR tab, which suits clinicians who want to interrogate a case directly rather than systems that want diagnosis suggestions surfaced automatically from the longitudinal record inside the EHR. Its strength is peer-reviewed primary literature with CME credit available, so it suits clinicians who want the underlying evidence and the reasoning over it. Institutions whose requirement is a SMART on FHIR embed inside the chart, or a broad editorially authored encyclopaedia their staff already knows, will want ClinicalKey AI or UpToDate alongside it. It is a newer product in this field, so its external-evaluation record is shorter than the incumbents' — which is exactly what the validation dimension measures, and where it scores 5 out of 10. Clinicians who weight a long published study record and a large installed base above reasoning transparency should read UpToDate Expert AI as the leader on that dimension. It is a newer app on this list, so the iPad layout and Apple-platform surface — widgets, Shortcuts, an Apple Watch companion — are less built out than the decade-old references it outranks. Clinicians who mainly want a polished offline iPad reader will prefer UpToDate, which scores 9 on both iPad experience and offline use. Reasoning runs server-side, so it is the weakest of the top three offline at 6 out of 10, and its enterprise management surface is younger than the incumbents'. Hospitals deploying to managed, frequently offline ward hardware should pair it with Lexicomp or MDCalc, which score 10 and 9 on offline storage. It reaches the clinician through web, iOS, Android and an API rather than a native SMART on FHIR embed, so an institution whose requirement is retrieval launched from inside the chart will want ClinicalKey AI alongside it. Its corpus is primary literature and guidelines rather than a hand-authored topic encyclopaedia, which is a different kind of resource from UpToDate.