Javascript Geocoding Tutorial

This is a tutorial for using the OpenCage geocoding API in Javascript.

Please note we also have tutorials for jQuery and nodejs.

You can also find SDKs for ReactJS, TypeScript, GatsbyJS, and various serverless platforms on our SDKs page.

If you are looking for an autosuggest search box functionality, please see our geosearch service.

Topics covered in this tutorial


The code examples below will use your geocoding API key once you log in.

Before we dive in to the tutorial

  1. Sign up for an OpenCage geocoding API key.
  2. Play with the demo page, so that you see the actual response the API returns.
  3. Browse the API reference, so you understand the optional parameters, best practices, possible response codes, and the rate limiting on free trial accounts.

Javascript geocoding example:

  var api_key = 'YOUR-API-KEY';

  // reverse geocoding example (coordinates to address)
  var latitude = '52.3877830';
  var longitude = '9.7334394';
  var query = latitude + ',' + longitude;

  // forward geocoding example (address to coordinate)
  // var query = 'Philipsbornstr. 2, 30165 Hannover, Germany';
  // note: query needs to be URI encoded (see below)

  var api_url = ''

  var request_url = api_url
    + '?'
    + 'key=' + api_key
    + '&q=' + encodeURIComponent(query)
    + '&pretty=1'
    + '&no_annotations=1';

  // see full list of required and optional parameters:

  var request = new XMLHttpRequest();'GET', request_url, true);

  request.onload = function() {
    // see full list of possible response codes:

    if (request.status === 200){
      // Success!
      var data = JSON.parse(request.responseText);
      alert(data.results[0].formatted); // print the location

    } else if (request.status <= 500){
      // We reached our target server, but it returned an error

      console.log("unable to geocode! Response code: " + request.status);
      var data = JSON.parse(request.responseText);
      console.log('error msg: ' + data.status.message);
    } else {
      console.log("server error");

  request.onerror = function() {
    // There was a connection error of some sort
    console.log("unable to connect to server");

  request.send();  // make the request


Some issues to consider:

Please note that putting your API key in client side javascript means that it is visible to anyone executing that javascript. We recommend you do this only for internal applications.

Please see our detailed guide to protecting your API key(s).

As an added measure of safety subscription customers can define a value for the Access-Control-Allow-Origin header in their account dashboard which will limit AJAX requests to a specific domain. You can find the details in the API documentation.

That being said, one worry that potential clients sometimes raise is that someone will get their key and start using it heavily and they will face a large and unexpected bill. Fear not - that can't happen because of how our pricing works. Subscription customers buy a month in advance, and there is no usage-based charging. If we see an explosion of usage we email you and ask if it is expected and the source is known. If yes, and it will be ongoing, we ask you to move to a higher pricing tier in the future, but this never happens as a surprise. If no, we can help you work out what is going on. Please see all the details of how our pricing works.

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2,500 geocoding API requests per day.

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