FHIR Endpoints & Rate Limits

Endpoint discovery, base URL structure, and rate limiting policies for eClinicalWorks FHIR R4 APIs.

Endpoint Structure

All eClinicalWorks FHIR R4 endpoints follow a consistent base URL pattern:

FHIR Base URL
https://{host}/fhir/r4/{practice_code}/

Each practice has a unique practice code that identifies it across the eCW platform. You can search for practices by name or code using the eCW Developer Portal at fhir.eclinicalworks.com/ecwopendev/fhir-endpoints. The portal also lets you download endpoints as a list for bulk configuration.

Discovery

Two standard discovery endpoints are available on every eCW FHIR server:

  • .well-known/smart-configurationReturns the SMART on FHIR configuration document, including the authorization and token endpoint URLs.
  • /metadataReturns the FHIR CapabilityStatement describing supported resources, search parameters, and operations.

Key Endpoints

Authorization
Standalone and EHR launch flows
{iss}/oauth2/authorize
Token
Exchange, refresh, and client_credentials
{iss}/oauth2/token
FHIR API
All FHIR R4 resource interactions
{base}/fhir/r4/{practice_code}/{Resource}

Rate Limiting

Rate Limits Enforced

Effective October 7, 2025, eClinicalWorks enforces a limit of 250 calls per minute per base URL across three rate-limited URL categories:

  • FHIR Resource API calls: /fhir/r4/{practice_code}/*
  • Authorization Code Requests: /authorize
  • Access Token Requests: /token

The rate limit counter is applied per base URL, meaning each practice code has its own independent quota. If your app is connected to multiple practices, the limits scale linearly:

  • 5 customers = 1,250 total requests/min
  • 20 customers = 5,000 total requests/min

When the limit is exceeded, the server responds with HTTP 429 Too Many Requests. All requests from that app are blocked for the remainder of the current minute. The counter resets at the beginning of every minute.