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CDS Hooks

CDS Hooks is an HL7 published specification for clinical decision support.

This site contains the various published versions of the specification. If you're looking for more general information on CDS Hooks or the development builds, you can find those at

Releases of the specification have been formally published through HL7.

Ballot versions are the precursors to a released version and go through a period of community feedback. They are archived here for historical posterity.

Hooks that have reached maturity level 4 or above (as described by the Hook Maturity Model) are published with the specification here. Proposed hooks (level 3 or below, are found at

The CDS Hooks specification is licensed under a Creative Commons Attribution 4.0 International License. All source code for CDS Hooks is available at

Version History

Version Date Description
1.0 2019-04-23 1.0 STU release (current)
2018May 2018-03-30 1.0 ballot (May 2018)

Change Log

1.0 Release

Changes since the 2018 May Ballot Version:

  • #187: Conformance requirements for JWT signing algorithms
  • #232: Moved user from the request to hook context definitions
  • #259: Removed the analytics endpoint pending further implementation experience
  • #320: Added a new required selectionBehavior field to cards
  • #340: Changed 'hard-stop' indicator value to 'critical'

In addition, numerous clarifications, corrections, and non-substantive updates were made to the specification based on ballot and implementer feedback. For a complete list of changes applied, see the issues under the 1.0 Milestone or the repository commit log.

2018May Ballot

This was the first STU ballot for the CDS Hooks specification. For a complete history of changes, see the repository commit log.