AngularJS $http POST default Content‑Type header – version‑dependent behavior

Default Content-Type Behavior

The default Content-Type header for $http.post() requests differs based on the AngularJS version:

• AngularJS 1.4.x and earlier: Defaults to application/x-www-form-urlencoded.
• AngularJS 1.5.x and newer: Defaults to application/json.

Runtime Version Detection

To determine the loaded version of AngularJS at runtime, access the angular.version.full property. This provides a string representation of the current release.

var currentVersion = angular.version.full;
console.log('Running AngularJS version: ' + currentVersion);

Compatibility Strategies for Upgrades

When migrating from 1.4.x to 1.5.x+, you can preserve legacy behavior using one of the following two methods, depending on whether the requirement is global or request-specific.

Option 1: Global Configuration (Recommended for Full Migration)

To force all POST requests to use the legacy form-urlencoded format, configure the $httpProvider during the application configuration phase. This prevents the need for runtime version checks across multiple controllers.

app.config(function($httpProvider) {
  $httpProvider.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded';
});

Option 2: Per-Request Override (Recommended for Hybrid APIs)

If your application communicates with both legacy (form-based) and modern (JSON-based) endpoints, explicitly define the header in the request configuration object.

$http.post('/api/legacy-endpoint', data, {
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
});

Verification and Diagnostics

To verify which header is being sent, use the browser's Developer Tools > Network Tab. Select the POST request and inspect the Request Headers section for the Content-Type key.

Diagnostic Note: If you are using a third-party interceptor or a wrapper service around $http, please specify if that wrapper modifies headers, as it may override the global $httpProvider settings.