Additional Headers

Add request headers when an API operation needs behavior beyond the ToolBox API defaults. Header names and values are strings, represented as Record<string, string>. Use only headers supported by the endpoint you are calling.

Overview

The Dataverse API names its final optional parameter additionalHeaders. The Power Platform API names its parameter headers. In both cases, pass a plain object of header-name and header-value pairs. Header names are case-insensitive in HTTP; the examples below use the casing shown in Microsoft documentation.

For Dataverse header requirements and behavior, see Microsoft's HTTP headers guidance.

Dataverse API

Dataverse network methods accept additionalHeaders?: Record<string, string> as their final argument, after connectionTarget. If you want to use the default primary connection, pass undefined for connectionTarget before the headers object. You can also pass a legacy connection alias or a zero-based slot index.

const accountRows = await dataverseAPI.queryData(
  'accounts?$select=name&$top=10',
  2,
  {
    'If-None-Match': 'null',
    Prefer:
      'odata.include-annotations="OData.Community.Display.V1.FormattedValue"',
  },
)

Here, 2 selects slot 2, and the headers apply to the outgoing Dataverse request. Pass the header object only when the requested operation requires those headers.

For example, to use the primary connection while supplying a header:

const account = await dataverseAPI.retrieve(
  'account',
  accountId,
  ['name'],
  undefined,
  { 'If-None-Match': 'null' },
)

Power Platform API

Power Platform API methods accept headers?: Record<string, string>. The signatures are Get(path?, connectionTarget?, headers?); Post, Put, and Patch use (path?, body?, connectionTarget?, headers?); and Delete uses (path?, connectionTarget?, headers?, body?).

const response = await window.powerplatformAPI.EnvironmentManagement.Get(
  'environments?api-version=2024-10-01',
  1,
  { Accept: 'application/json' },
)

See the PowerPlatform API reference for the parameter order of each HTTP method.

Common Dataverse Headers

Header support and effects depend on the Dataverse operation. Consult the Microsoft documentation for the specific header and operation before using it. In batch requests, per-operation headers belong on each BatchRequest; additionalHeaders applies to the outer batch request.