# Provenance stamped 2026-10-07 (roadmap#943): written by an API Evangelist sweep (dated 2026-06-13 by the file itself), not
# harvested from the provider. `method: generated` so the economics campaign may replace it with a
# dated, verbatim transcription; every figure below is unverified until it does.
method: generated
generated: '2026-06-13'
specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Microsoft Azure Health Data Services
providerId: microsoft-azure-health-data-services
created: '2026-06-13'
modified: '2026-06-13'
reconciled: true
tags:
  - Rate Limiting
  - FHIR
  - DICOM
  - De-identification
  - Healthcare
  - Microsoft Azure
description: >-
  Azure Health Data Services enforces rate limits per service. FHIR service
  throughput scales with provisioned RU/s (automatically managed by Azure —
  not manually configurable). DICOM service handles thousands of image ingestions
  per second but doesn't publish explicit per-second request caps. The
  de-identification service throttles at 1 MB per 5 seconds or 100 requests
  per 5 seconds. When limits are exceeded, the service returns HTTP 429
  (Too Many Requests). Higher throughput is available by submitting a support
  request.
sources:
  - https://learn.microsoft.com/en-us/azure/healthcare-apis/deidentification/overview#input-requirements-and-service-limits
  - https://learn.microsoft.com/en-us/azure/healthcare-apis/fhir/overview
  - https://learn.microsoft.com/en-us/azure/healthcare-apis/dicom/overview
headers:
  requestId: x-ms-request-id
  correlationId: x-ms-correlation-request-id
responseCodes:
  rateLimitExceeded: 429
  serviceUnavailable: 503
limits:
  - name: De-identification service — request size
    scope: request
    metric: payload_size
    limit: '50 KB'
    timeFrame: per-request
    notes: Each synchronous de-identification request body must not exceed 50 KB.
  - name: De-identification service — throughput (bandwidth)
    scope: service-instance
    metric: mb_per_window
    limit: 1
    timeFrame: 5_seconds
    notes: >-
      Requests are throttled when total data volume exceeds 1 MB per 5-second
      window. Submit a support request for higher throughput.
  - name: De-identification service — request rate
    scope: service-instance
    metric: requests_per_window
    limit: 100
    timeFrame: 5_seconds
    notes: >-
      Requests are throttled when request count exceeds 100 per 5-second
      window. Submit a support request for higher limits.
  - name: De-identification service — async job documents
    scope: job
    metric: documents
    limit: 10000
    timeFrame: per-job
    notes: Each asynchronous batch job can process no more than 10,000 documents.
  - name: De-identification service — document size (async jobs)
    scope: document
    metric: payload_size
    limit: '2 MB'
    timeFrame: per-document
    notes: Each individual document submitted in an async batch job must not exceed 2 MB.
  - name: De-identification service — free monthly allotment
    scope: service-instance
    metric: mb
    limit: 50
    timeFrame: month
    notes: >-
      50 MB of de-identification included free each month per service instance
      before usage-based charges apply.
  - name: FHIR service — throughput (RU/s)
    scope: service-instance
    metric: request_units_per_second
    limit: -1
    timeFrame: second
    notes: >-
      Throughput is automatically managed by Azure and scales elastically.
      Manual RU/s provisioning is not available in Azure Health Data Services
      FHIR service (unlike Azure API for FHIR). Contact support for throughput
      capacity discussions.
  - name: DICOM service — ingestion capacity
    scope: service-instance
    metric: images_per_second
    limit: -1
    timeFrame: second
    notes: >-
      Designed to ingest multiple thousands of DICOM images per second.
      Exact cap is not published; scales to petabyte-level imaging archives.
      Contact support for capacity planning.
  - name: MedTech service — device messages
    scope: service-instance
    metric: messages_per_second
    limit: -1
    timeFrame: second
    notes: >-
      No documented hard cap per second; throughput scales with the Azure
      Event Hub partition count configured as the device message input.
policies:
  - name: Retry on 429 with exponential backoff
    description: >-
      When the de-identification service returns HTTP 429, clients should
      implement exponential backoff with jitter before retrying. The
      Retry-After header may indicate the recommended wait time.
  - name: Support request for higher throughput
    description: >-
      For FHIR, DICOM, or de-identification workloads requiring throughput
      above default limits, submit an Azure support request for consideration
      of higher capacity allocations.
  - name: Private Link for network isolation
    description: >-
      Enable Azure Private Link to route all API traffic through private
      endpoints, reducing exposure to public internet throttling and
      network-layer limitations.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com