Authentication and Authorization

Business-specific parameters

When using a Maps API web service in your Google Maps API for Work application, two parameters are required in addition to the standard parameters:

  • Your client ID. To access the special features of the Google Maps API for Work you must provide a client ID when accessing any of the API libraries or services. When registering for Google Google Maps API for Work you will receive this client ID from Enterprise Support. All client IDs begin with a gme- prefix. Your client ID is passed as the value of the client parameter.
  • A unique signature, generated using your cryptographic key. This is passed as the value of the signature parameter. More information about generating a signature can be found below, in the Digital Signatures section.

The Google Places API and Google Maps Geolocation API do not use the client and signature parameters. These APIs use a key parameter, obtained from the API Console. For more information, refer to the Places API and Geolocation API documentation.


In addition, the following parameter is optional with Google Maps API for Work requests:

  • channel is used to provide additional reporting detail, by grouping different channels separately in your reports. Refer to the Channel reports section of the Quota and reporting page of this document.

For information about a specific service's standard parameters, please refer to that service's documentation.

Digital signatures

Requests to these Maps API web services by Google Maps API for Work applications require digital signatures, generated using a cryptographic key provided to you for that purpose. The signing process combines a URL and the key together using an encryption algorithm. The resulting unique signature allows our web services to verify that any site generating requests using your client ID are authorized to do so.

How do I get my signing key?

Your cryptographic URL-signing key will be issued with your client ID and is a "secret shared key" between you and Google. Client IDs are issued to all Google Maps API for Work customers. This signing key is yours alone and unique to your client ID. For that reason, please keep your signing key secure. This key — though used to generate the signature — should not be passed within any requests, stored on any websites, or posted to any public forum. Anyone obtaining this signing key "in the clear" could spoof requests using your identity.

Note: This cryptographic signing key is not the same as a key issued by the Google APIs Console for use with freely available Google APIs.

If you've lost your signing key, log in to the Google for Work Support Portal and click Maps: Manage Client ID to retrieve it.

Generating valid signatures

Attempting to access a web service with an invalid signature will result in a HTTP 403 (Forbidden) error. As you convert your applications to use URL signing, make sure to test your signatures to ensure they initiate a valid request. You should first test whether the original URL is valid (See Building a Valid URL in the Web Services documentation) as well as test whether you generate the correct signatures.

A screencast with a step by step explanation can be found on the Google Developers YouTube channel: Google Maps API for Work Generating Valid Signatures.

To create a valid signature for your request:

  1. Construct your URL, making sure to include your client parameter. Note that any non-standard characters will need to be URL-encoded:


  2. Strip off the domain portion of the request, leaving only the path and the query:


  3. Retrieve your private key, which is encoded in a modified Base64 for URLs, and sign the URL above using the HMAC-SHA1 algorithm. You may need to decode this key into its original binary format. Note that in most cryptographic libraries, the resulting signature will be in binary format.

  4. Encode the resulting binary signature using the modified Base64 for URLs to convert this signature into something that can be passed within a URL.

  5. Attach this signature to the URL within a signature parameter:


Signature examples

The following sections show ways to implement URL signing using server-side code. URLs should always be signed server-side to avoid exposing your cryptographic key to users.


The example below uses standard Python libraries to sign a URL. (Download the code.)

# -*- coding: utf-8 -*-
""" Signs a URL using a URL signing secret """

import hashlib
import hmac
import base64
import urlparse

def sign_url(input_url=None, secret=None):
  """ Sign a request URL with a URL signing secret.
      from urlsigner import sign_url
      signed_url = sign_url(input_url=my_url, secret=SECRET)
      input_url - The URL to sign
      secret    - Your URL signing secret
      The signed request URL

  if not input_url or not secret:
    raise Exception("Both input_url and secret are required")

  url = urlparse.urlparse(input_url)

  # We only need to sign the path+query part of the string
  url_to_sign = url.path + "?" + url.query

  # Decode the private key into its binary format
  # We need to decode the URL-encoded private key
  decoded_key = base64.urlsafe_b64decode(secret)

  # Create a signature using the private key and the URL-encoded
  # string using HMAC SHA1. This signature will be binary.
  signature = hmac.new(decoded_key, url_to_sign, hashlib.sha1)

  # Encode the binary signature into base64 for use within a URL
  encoded_signature = base64.urlsafe_b64encode(signature.digest())

  original_url = url.scheme + "://" + url.netloc + url.path + "?" + url.query

  # Return signed URL
  return original_url + "&signature=" + encoded_signature

if __name__ == "__main__":
  input_url = raw_input("URL to Sign: ")
  secret = raw_input("URL signing secret: ")
  print "Signed URL: " + sign_url(input_url, secret)

The example below uses the java.util.Base64 class available since JDK 1.8 - older versions may need to use Apache Commons or similar. (Download the code.)


import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;  // JDK 1.8 only - older versions may need to use Apache Commons or similar.
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.net.URL;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class UrlSigner {

  // Note: Generally, you should store your private key someplace safe
  // and read them into your code

  private static String keyString = "YOUR_PRIVATE_KEY";

  // The URL shown in these examples is a static URL which should already
  // be URL-encoded. In practice, you will likely have code
  // which assembles your URL from user or web service input
  // and plugs those values into its parameters.
  private static String urlString = "YOUR_URL_TO_SIGN";

  // This variable stores the binary key, which is computed from the string (Base64) key
  private static byte[] key;

  public static void main(String[] args) throws IOException,
    InvalidKeyException, NoSuchAlgorithmException, URISyntaxException {

    BufferedReader input = new BufferedReader(new InputStreamReader(System.in));

    String inputUrl, inputKey = null;

    // For testing purposes, allow user input for the URL.
    // If no input is entered, use the static URL defined above.    
    System.out.println("Enter the URL (must be URL-encoded) to sign: ");
    inputUrl = input.readLine();
    if (inputUrl.equals("")) {
      inputUrl = urlString;

    // Convert the string to a URL so we can parse it
    URL url = new URL(inputUrl);

    // For testing purposes, allow user input for the private key.
    // If no input is entered, use the static key defined above.   
    System.out.println("Enter the Private key to sign the URL: ");
    inputKey = input.readLine();
    if (inputKey.equals("")) {
      inputKey = keyString;

    UrlSigner signer = new UrlSigner(inputKey);
    String request = signer.signRequest(url.getPath(),url.getQuery());

    System.out.println("Signed URL :" + url.getProtocol() + "://" + url.getHost() + request);

  public UrlSigner(String keyString) throws IOException {
    // Convert the key from 'web safe' base 64 to binary
    keyString = keyString.replace('-', '+');
    keyString = keyString.replace('_', '/');
    System.out.println("Key: " + keyString);
    // Base64 is JDK 1.8 only - older versions may need to use Apache Commons or similar.
    this.key = Base64.getDecoder().decode(keyString);

  public String signRequest(String path, String query) throws NoSuchAlgorithmException,
    InvalidKeyException, UnsupportedEncodingException, URISyntaxException {

    // Retrieve the proper URL components to sign
    String resource = path + '?' + query;

    // Get an HMAC-SHA1 signing key from the raw key bytes
    SecretKeySpec sha1Key = new SecretKeySpec(key, "HmacSHA1");

    // Get an HMAC-SHA1 Mac instance and initialize it with the HMAC-SHA1 key
    Mac mac = Mac.getInstance("HmacSHA1");

    // compute the binary signature for the request
    byte[] sigBytes = mac.doFinal(resource.getBytes());

    // base 64 encode the binary signature
    // Base64 is JDK 1.8 only - older versions may need to use Apache Commons or similar.
    String signature = Base64.getEncoder().encodeToString(sigBytes);

    // convert the signature to 'web safe' base 64
    signature = signature.replace('+', '-');
    signature = signature.replace('/', '_');

    return resource + "&signature=" + signature;

The example below uses the default System.Security.Cryptography library to sign a URL request. Note that we need to convert the default Base64 encoding to implement a URL-safe version. (Download the code.)


using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;

namespace SignUrl {

  public struct GoogleSignedUrl {

    public static string Sign(string url, string keyString) {
      ASCIIEncoding encoding = new ASCIIEncoding();

      // converting key to bytes will throw an exception, need to replace '-' and '_' characters first.
      string usablePrivateKey = keyString.Replace("-", "+").Replace("_", "/");
      byte[] privateKeyBytes = Convert.FromBase64String(usablePrivateKey);

      Uri uri = new Uri(url);
      byte[] encodedPathAndQueryBytes = encoding.GetBytes(uri.LocalPath + uri.Query);

      // compute the hash
      HMACSHA1 algorithm = new HMACSHA1(privateKeyBytes);
      byte[] hash = algorithm.ComputeHash(encodedPathAndQueryBytes);

      // convert the bytes to string and make url-safe by replacing '+' and '/' characters
      string signature = Convert.ToBase64String(hash).Replace("+", "-").Replace("/", "_");

      // Add the signature to the existing URI.
      return uri.Scheme+"://"+uri.Host+uri.LocalPath + uri.Query +"&signature=" + signature;

  class Program {

    static void Main() {

      // Note: Generally, you should store your private key someplace safe
      // and read them into your code

      const string keyString = "YOUR_PRIVATE_KEY";

      // The URL shown in these examples is a static URL which should already
      // be URL-encoded. In practice, you will likely have code
      // which assembles your URL from user or web service input
      // and plugs those values into its parameters.
      const  string urlString = "YOUR_URL_TO_SIGN";

      string inputUrl = null;
      string inputKey = null;

      Console.WriteLine("Enter the URL (must be URL-encoded) to sign: ");
      inputUrl = Console.ReadLine();
      if (inputUrl.Length == 0) {
        inputUrl = urlString;

      Console.WriteLine("Enter the Private key to sign the URL: ");
      inputKey = Console.ReadLine();
      if (inputKey.Length == 0) {
        inputKey = keyString;


For testing purposes, you can test the following URL and private key to see if it generates the correct signature. Note that this private key is purely for testing purposes and will not be validated by any Google services.

  • URL: https://maps.googleapis.com/maps/api/geocode/json?address=New+York&client=clientID
  • Private Key: vNIXE0xscrmjlyV-12Nj_BvUPaw=
  • URL Portion to Sign: /maps/api/geocode/json?address=New+York&client=clientID
  • Signature: chaRF2hTJKOScPr-RQCEhZbSzIE=
  • Full Signed URL: https://maps.googleapis.com/maps/api/geocode/json?address=New+York&client=clientID&signature=chaRF2hTJKOScPr-RQCEhZbSzIE=

Examples in additional languages

Examples that cover more languages are available in the js-v2-samples project.

Troubleshooting authentication issues

In the event your request is malformed or supplies an invalid signature, you will encounter an HTTP 403 (Forbidden) error along with the message:

Unable to authenticate the request. Provided 'signature' is not valid for the provided client ID. Learn more:

To troubleshoot individual URLs, a URL signing debugger is available for the purpose of quickly validating URLs and signatures generated by your application. You can access the tool from:


or by logging in to the Google for Work Support Portal and selecting Resources > Google Maps API for Work online tools > URL Signing Debugger for Web Service and Image APIs.

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