Time Zone API: Get an API Key

Note: The Google Maps Platform Premium Plan is no longer available for sign up or new customers.

Choosing an authentication method

To use the Google Maps Platform, you must authenticate requests using an API key or a client ID and digital signature.

The authentication method you choose is based on your license:

  • Customers with the Premium Plan can use an API key or a client ID and digital signature.
  • Customers with a previous license must use a client ID and digital signature.

When deciding which authentication method to use, consider the following:

  • Authentication using an API key (Premium Plan)
    By using an API key to authenticate your request, you can:
    • Manage all of your APIs on the APIs page of the Google Cloud Console.
    • Access real-time usage data and 30 days of historical usage data on the APIs page of the Cloud Console.
    • Add the channel parameter to requests so you can view more detailed usage reports.
    • View usage reports with more than 30 days of data in the Google Cloud Console.
  • Authentication using a client ID and digital signature (Premium Plan or previous license)
    By using your client ID and digital signature to authenticate your request, you can:
    • Add the channel parameter to requests so you can view more detailed usage reports.
    • View usage reports with more than 30 days of data in the Cloud Console.
    • Use Maps Analytics tools for the Maps JavaScript API.

Get more information on reports available to Premium Plan customers.

Authentication using an API key

Getting the API key

The API key is a unique identifier that is used to authenticate requests associated with your project for usage and billing purposes.

To get an API key:

  1. In the Cloud Console, on the project selector page, select or create a Google Cloud project for which you want to add an API Key.

    Go to the project selector page

    Note: To have full access to the features in their plan, Premium customers should use the project associated with their Premium account. When you purchased your license, you received the name of your Premium asset in the following format: gme-[company] & proj-[number] ([type]). To ensure you are accessing the correct project, log in to the console as the project owner using console.cloud.google.com/project/number (replace number with your project number). You can locate the project owner in your welcome letter.

  2. Go to the APIs & Services > Credentials page.

    Go to the Credentials page

  3. On the Credentials page, click Create credentials > API key.
    The API key created dialog displays your newly created API key.
  4. Click Close.
    The new API key is listed on the Credentials page under API keys.
    (Remember to restrict the API key before using it in production.)

Adding the API key to your request

You must include an API key with every Google Maps Platform request. In the following example, replace YOUR_API_KEY with your API key.


HTTPS is required for requests that use an API key, and recommended for requests that use a client ID. HTTPS is also required for applications that include sensitive user data - such as a user's location - in requests.

Restricting API keys

Restricting API Keys adds security to your application by ensuring only authorized requests are made with your API Key. We strongly recommend that you follow the instructions to set restrictions for your API Keys. For more information, see API Key best practices.

To restrict an API key:

  1. Go to the APIs & Services > Credentials page.

    Go to the Credentials page

  2. Select the API key that you want to set a restriction on. The API key property page appears.
  3. Under Key restrictions, set the following restrictions:
    • Application restrictions:
      1. To accept requests from the list of web server IP addresses that you supply, select IP addresses (web servers, cron jobs, etc.) from the list of Application restrictions.
      2. Specify one IPv4 or IPv6 address or a subnet using CIDR notation (e.g. If you need to enter another entry, a new box appears after you complete adding the previous entry.
    • API restrictions:
      1. Click Restrict key.
      2. Select Google Maps Platform from Select APIs dropdown. If the Google Maps Platform is not listed, you need to enable it.
  4. To finalize your changes, click Save.

Authenticating using a client ID and digital signature

Upon purchasing your Google Maps Platform Premium Plan license, you will receive a welcome email from Google that contains your client ID and your private cryptographic key (which you can use to generate a unique digital signature).

The code example below shows you the client and signature parameters to which you must pass your client ID and unique digital signature.

  • Replace YOUR_CLIENT_ID with the client ID contained in your welcome email.

    Your client ID begins with the characters gme-.

  • Replace SIGNATURE with your unique digital signature (see Generating a digital signature).


  • As an option, you can use the channel parameter when authenticating the Google Maps Platform using a client ID and digital signature to receive detailed usage reports. Refer the Premium Plan Reporting Overview for more information.
  • If you were previously using an API key for authentication and are switching to using a client ID, you must remove the key parameter from your requests. Google Maps APIs web services will deny requests made with both a client ID and an API key.

Generating a digital signature

Requests to the Time Zone API by Google Maps Platform Premium Plan customers require a digital signature that you can generate using the private cryptographic key provided to you in your welcome email (see More about your private cryptographic key).

Follow the steps below to generate a digital signature for your request.

  1. Construct the request URL without the signature, making sure to include your client parameter. Note that any non-standard characters will need to be URL-encoded:


    Note: All Google services require UTF-8 character encoding (which implicitly includes ASCII). If your applications operate using other character sets, make sure they construct URLs using UTF-8 and properly URL-encode them.

  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.

    Note: Modified Base64 for URLs replaces the + and / characters of standard Base64 with - and _ respectively, so that these Base64 signatures no longer need to be URL-encoded.

  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:



  • The unique signature allows our servers to verify that any site generating requests using your client ID are authorized to do so. The signature is also unique per URL, ensuring that requests that use your client ID cannot be modified without requiring a new signature to be generated.
  • Attempting to access the Time Zone API 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 as well as test whether you generate the correct signatures.
  • For samples showing ways to implement URL signing using server-side code, see Sample code for URL signing.

To sign a URL now, enter your URL and your URL signing secret below. The URL must have the format described in step 1 above, and be URL-encoded.

Sample code for URL signing

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 urllib.parse as 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, str.encode(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.decode()

if __name__ == "__main__":
    input_url = input("URL to Sign: ")
    secret = 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;

Node JS

The example below uses native Node modules to sign a URL. (Download the code.)

'use strict'

const crypto = require('crypto');
const url = require('url');

 * Convert from 'web safe' base64 to true base64.
 * @param  {string} safeEncodedString The code you want to translate
 *                                    from a web safe form.
 * @return {string}
function removeWebSafe(safeEncodedString) {
  return safeEncodedString.replace(/-/g, '+').replace(/_/g, '/');

 * Convert from true base64 to 'web safe' base64
 * @param  {string} encodedString The code you want to translate to a
 *                                web safe form.
 * @return {string}
function makeWebSafe(encodedString) {
  return encodedString.replace(/\+/g, '-').replace(/\//g, '_');

 * Takes a base64 code and decodes it.
 * @param  {string} code The encoded data.
 * @return {string}
function decodeBase64Hash(code) {
  // "new Buffer(...)" is deprecated. Use Buffer.from if it exists.
  return Buffer.from ? Buffer.from(code, 'base64') : new Buffer(code, 'base64');

 * Takes a key and signs the data with it.
 * @param  {string} key  Your unique secret key.
 * @param  {string} data The url to sign.
 * @return {string}
function encodeBase64Hash(key, data) {
  return crypto.createHmac('sha1', key).update(data).digest('base64');

 * Sign a URL using a secret key.
 * @param  {string} path   The url you want to sign.
 * @param  {string} secret Your unique secret key.
 * @return {string}
function sign(path, secret) {
  const uri = url.parse(path);
  const safeSecret = decodeBase64Hash(removeWebSafe(secret));
  const hashedSignature = makeWebSafe(encodeBase64Hash(safeSecret, uri.path));
  return url.format(uri) + '&signature=' + hashedSignature;


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 url-signing project.

More about your private cryptographic key

Your private cryptographic URL-signing key will be issued with your client ID and is a "secret shared key" between you and Google. This signing key is yours alone and is unique to your client ID. For that reason, please keep your signing key secure. This key should not be passed within any requests, stored on any websites, or posted to any public forum. Anyone obtaining this signing key could spoof requests using your identity.

Note: This private cryptographic signing key is not the same as the API keys issued by the Google Cloud Console.

If you've lost your private cryptographic key, log in to the Cloud Console and click Maps: Manage Client ID to retrieve it.

Troubleshooting authentication issues

If your request is malformed or supplies an invalid signature, the Google Maps Platform returns an HTTP 403 (Forbidden) error.

To troubleshoot individual URLs, you can use the URL Signing Debugger. It allows you to quickly validate a URL and signature generated by your application.

Alternatively, Premium Plan customers can troubleshoot individual URLs by logging in to the Cloud Console and selecting Resources > Google Maps Platform Premium Plan online tools > URL Signing Debugger for Web Service and Image APIs.