eClinicalWorks (eCW) API integration guide: versions, healow and FHIR
- Access model
- Open self-registration + practice activation
- Developer program
- eCW FHIR portal + healow developer portal
- Certified FHIR access
- FHIR R4 (US Core), read APIs
- Scheduling write
- Not published
The short answer
eClinicalWorks (eCW) publishes certified FHIR APIs that any developer can register for, free "at this time" per eCW. Each practice then switches the APIs on and opts your app in. The published surface is read: clinical data out, not appointments or notes in. Plan scheduling and write-back as a separate problem from day one.
The eCW flavors to tell apart
"We're on eCW" covers several different setups. Ask which one before you scope.
| Flavor | What it means for an integration |
|---|---|
| V11 (certified build 11.52.305C) | Runs in Chrome as the web version, and eCW's disclosure says it's also available as a desktop executable. Older installs are common. |
| V12 (certified builds 12.0.1 to 12.0.3) | Announced Oct 2022 as the browser and cloud format. Whether a desktop client remains is not stated in eCW's public material. |
| Licensed, customer-hosted | Upfront licence; the practice (or its IT provider) runs the servers. eCW lets these customers pay eCW to host instead. |
| eCW cloud subscription | eCW hosts; hosting is included. eCW also sells an RCM-with-cloud bundle. |
| healow | eCW's patient-facing family: the healow app and portal, healow Open Access (self-scheduling), healow Genie (AI contact center) and more. Patient-facing API apps register on the healow portal. |
| eCW's own add-ons | Sunoh.ai (ambient scribe, developed by healow), PRISMA (outside-records search), plus RCM services. If your product overlaps one, expect the practice to compare you with it. |
Two things to confirm on every eCW deal: the version and who hosts. eCW doesn't publish whether API activation differs by hosting model, so ask the practice's eCW admin early.
How access works
- Pick the portal. Provider-facing, SMART EHR-launch and backend or bulk apps register on the eCW FHIR portal (fhir.eclinicalworks.com). Patient-facing apps register on the healow developer portal (connect4.healow.com).
- Register and test. Sign-up is self-service. Build against the shared sandbox; eCW reviews registered apps before they reach production.
- The practice activates. Each practice enables the FHIR APIs through eCW's Product Activation / On-Demand Activation, then opts your app in. Budget calendar time for both gates.
- Respect the rate limit. eCW's Nov 2025 certification disclosure states no more than 25 calls per minute per base URL on the FHIR, authorize and token endpoints, with HTTP 429 beyond that.
What the APIs cover
| Job | Path on eCW |
|---|---|
| Patient and clinical read | Certified FHIR R4 read APIs (USCDI v1 and v3 resource sets), SMART on FHIR |
| Population export | Bulk FHIR (multi-patient) for backend apps |
| Full record export | EHI Export, documented at ehi.eclinicalworks.com |
| Book or change appointments | No public write API. healow Open Access is eCW's own self-scheduling product |
| File a note or document into the chart | No public write API |
| Auth | OAuth 2.0 / SMART App Launch; private-key JWT preferred, PKCE (S256) |
What it costs
eCW states its certified FHIR APIs are free to third-party developers and customers at this time, and that it will give at least 30 days' notice before adding licensing or usage fees. It may sell value-added services separately.
Our take
eCW is one of the easiest EMRs to read from and one of the hardest to write into. For the read side, use the certified APIs and design around 25 calls a minute: cache, batch, and use bulk export for anything population-wide. For scheduling and chart actions, the pattern we've seen work is APIs plus an agent: the certified APIs for data, and for the actions they don't cover, an automation running under the practice's own named eCW user, with scoped permissions and a full audit trail. Read eCW's terms and the practice's agreement first; that decision belongs to the practice. And price in the version and hosting conversation, because it changes timelines more than the code does.
FAQ
Does eClinicalWorks have an API?
Yes. eCW publishes certified FHIR R4 APIs on two portals: fhir.eclinicalworks.com for provider and backend apps, and connect4.healow.com for patient apps.
Can you book appointments in eClinicalWorks through the API?
Not through a published public API. eCW's documented FHIR surface is read-only, and its own self-scheduling product is healow Open Access.
What's the difference between eCW V11 and V12?
V12 is eCW's browser and cloud-format release, announced in 2022. V11 runs in Chrome too, and its certified build is also available as a desktop executable. Confirm which one each practice runs.
Is the eClinicalWorks API free?
eCW states its certified FHIR APIs are free at this time, with 30 days' notice before any fees.
Sources
Public pages, accessed 11 Oct 2026: eCW certified EHR technology · eCW ONC certification and costs disclosure, Nov 2025 (PDF) · eCW FHIR developer portal · healow developer portal · eCW interoperability · healow Open Access · eCW V12 announcement
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