Special thanks to Adam Culbertson, Cooper Thompson, Josh Mandel, and Brandon LaRue for fact checking historical details and providing general input into this piece.
The current state of patient appointment scheduling
Patients face barriers to securing timely appointments, driven by a combination of appointment opacity and provider workforce shortages. The typical search process entails patients using search engines, word of mouth, or third-party platforms to identify preferred providers. They will then check payer directories to confirm in-network status. Actual scheduling then involves navigating provider portals or calling offices directly. We covered this in detail in our post Empowering Patient Choice. This fragmented workflow creates friction, limiting visibility into available time slots and delaying access to care. As a result, patients wait an average of 38 days—and in some markets up to six months for certain specialties—before securing appointments.
Increasing appointment transparency during the COVID-19 pandemic
A few months after COVID-19 vaccines became available, the interoperability community, including Josh Mandel, US Digital Response, EHR vendors, and major retail pharmacy chains, collaborated to develop a lightweight specification for publishing vaccine appointment slots. This approach, known as SMART Scheduling Links, allowed sites to publish appointments in machine-readable files organized under a simple index–manifest structure. The design minimized infrastructure requirements: publishers only needed to host static data files, which existing web crawlers from Google, Apple, the U.S. Digital Service, and Vaccines.gov could ingest and publish on their respective web properties. This initiative demonstrated how disparate stakeholders could coordinate around a standard to expose appointment availability and drive efficient utilization at national scale.
Generalizing SMART Scheduling Links
Even during the COVID-19 pandemic, innovators began exploring how the SMART Scheduling Links specification could be generalized beyond vaccinations. At the May 2025 HL7 meeting in Madrid, Adam Culbertson of b.well convened a Birds of a Feather session to assess the state of interoperable appointment standards. By July 2025, Zocdoc, Optum, and Defacto Health joined the effort, focusing on extending SMART Scheduling Links to support a wider range of healthcare appointment scenarios. Key enhancements included the introduction of PractitionerRole as a resource that can be logically linked to Schedules and Slots, enabling richer semantic relationships between providers and their appointment slots. To facilitate testing, Zocdoc deployed a reference server that published sample appointment slots, creating a controlled environment for early testing ahead of the HL7 Connectathon.
SMART Scheduling Links complements existing standards like Argonaut Scheduling IG and Da Vinci Plan-Net by addressing different layers of the scheduling workflow. While Argonaut provides an API framework that enables the actual booking of appointments, SMART Scheduling Links abstracts this process by exposing a deep booking link that can be syndicated broadly and aggregated across provider organizations. Meanwhile, Plan-Net defines key resources such as Location, Insurance, Specialty (captured in PractitionerRole), and HealthcareService, which can be integrated with SMART Scheduling Links to enhance discovery and search functionality, allowing patients to efficiently find appointment slots using even richer query criteria.
Connectathon Testing
The Patient Scheduling track demonstrated progress with SMART Scheduling Links. Five organizations developed client apps that queried the reference server and successfully executed all three test scenarios: appointment discovery, appointment search, and booking via deep links. Two applications integrated insurance data using UnitedHealthcare’s Provider Directory API. All clients implemented basic search, including filtering by specialty, location, and appointment date range, validating the feasibility of a standardized approach to appointment discovery and scheduling. We also received input and feedback from providers, payers, government agencies, associations, and EHR vendors, which will inform future specification updates and real-world implementation.
Several key ideas emerged during the discussions. These included incorporation of Insurance, Organization, and HealthcareService resources, as well as considerations around appointment types. Significant attention was given to questionnaires that gate appointment slot publishing in many health systems. A review of the top 30 health systems revealed that 25 offer online appointment booking, and 24 publicly published appointment slots, indicating openness among health systems to expose scheduling data in a standardized, machine-readable format.
This use case represents a scenario in which incentives are aligned across stakeholders:
- Patients benefit from a more integrated search experience, enabling them to locate timely, in-network care across provider organizations.
- Provider organizations can reduce the cost of patient acquisition and optimize appointment utilization by presenting appointments wherever patients are searching.
- Payers improve member access to care, which supports member satisfaction metrics and may positively impact quality ratings, while also addressing challenges with incomplete or outdated provider directory data.
- Third-party platforms gain the ability to more effectively connect patients with providers by leveraging standardized and aggregated appointment data.
- The federal government (CMS) consistently highlights appointment scheduling alongside Patient Access to data, the National Directory, and other current priorities, underscoring the national significance of improving scheduling interoperability.
The National Directory initiatives led by CMS could be substantially strengthened by incorporating appointment scheduling capabilities. Exposing bookable appointments would allow patients to not only locate providers but also secure care more quickly. Enriching this scheduling layer with contextual data—such as accepted insurance plans, practice locations, and languages spoken—would help patients make informed choices about which provider best meets their needs. Appointment metadata could also improve data quality within provider directories, particularly for fields known to suffer from inaccuracies such as Accepting New Patients. Beyond directory accuracy, integrating bookable appointment slots would increase the practical utility of adjacent APIs, including the Provider Directory API and Patient Access API, since patients engaged in digital appointment workflows are more likely to retrieve their own records and interact with both payers and providers digitally.
Next Steps
The Connectathon provided an initial validation of SMART Scheduling Links, testing key use cases and demonstrating industry interest. All test scenarios were executed successfully, and representatives across providers, payers, EHR vendors, and third-party platforms actively participated and expressed support for the use case.
Moving forward, specification updates will be necessary, along with engagement with stakeholders to review and refine these updates. Subsequent phases will focus on real-world implementation, identifying one or more health systems willing to publish appointment slots in the standardized format, and collaborating with EHR or scheduling platform to operationalize the standard. Continued engagement with providers, payers, and third-party platforms will ensure adoption, facilitate feedback, and support broader interoperability in patient scheduling.