Set up the JavaScript fleet tracking library
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Before using the JavaScript fleet tracking library, make sure you are
familiar with and have set up Fleet Engine. For details, see
Fleet Engine.
This document shows how to enable authorization between the
web page app and Fleet Engine. Once your requests to Fleet Engine have
been set up with the correct authorization tokens, you'll be ready to
track a vehicle on a map.
Set up authorization
Fleet Engine requires the use of JSON Web Tokens (JWTs) for API method calls
from low-trust environments: smartphones and browsers.
A JWT originates on your server, is signed, encrypted, and passed to the client
for subsequent server interactions until it expires or is no longer valid.
Key details
How does authorization work?
Authorization with Fleet Engine data involves both server-side and client-side
implementation.
Server-side authorization
Before you set up authentication and authorization in your Fleet tracking
application, your backend server must be able to issue JSON Web Tokens to your
Fleet tracking application for access to Fleet Engine. Your Fleet tracking application
sends these JWTs with its requests so Fleet Engine recognizes the requests as
authenticated and authorized to access the data in the
request. For instructions on server-side JWT implementation, see Issue JSON Web
Tokens under Fleet Engine Essentials.
To generate tokens from your server when implementing Fleet tracking, see the
following:
Client-side authorization
When you use the JavaScript Fleet tracking library, it requests a token from the server using an
authorization token fetcher. It does this when any of the following is true:
No valid token exists, such as when the SDK hasn't called the fetcher on a
fresh page load, or when the fetcher hasn't returned with a token.
The token has expired.
The token is within one minute of expiring.
Otherwise, the JavaScript Fleet tracking library uses the previously-issued, valid token and does not
call the fetcher.
Create an authorization token fetcher
Create your authorization token fetcher using these guidelines:
The fetcher must return a data structure with two fields, wrapped in a
Promise
as follows:
The fetcher should call a URL on your server to retrieve a token. This
URL--the SERVER_TOKEN_URL
--depends on your backend implementation. The
following example URL is for the sample app backend on GitHub:
https://SERVER_URL/token/fleet_reader
Example - Create an authorization token fetcher
The following examples show how to create an authorization token fetcher:
JavaScript
async function authTokenFetcher(options) {
// options is a record containing two keys called
// serviceType and context. The developer should
// generate the correct SERVER_TOKEN_URL and request
// based on the values of these fields.
const response = await fetch(SERVER_TOKEN_URL);
if (!response.ok) {
throw new Error(response.statusText);
}
const data = await response.json();
return {
token: data.Token,
expiresInSeconds: data.ExpiresInSeconds
};
}
TypeScript
function authTokenFetcher(options: {
serviceType: google.maps.journeySharing.FleetEngineServiceType,
context: google.maps.journeySharing.AuthTokenContext,
}): Promise<google.maps.journeySharing.AuthToken> {
// The developer should generate the correct
// SERVER_TOKEN_URL based on options.
const response = await fetch(SERVER_TOKEN_URL);
if (!response.ok) {
throw new Error(response.statusText);
}
const data = await response.json();
return {
token: data.token,
expiresInSeconds: data.ExpiresInSeconds,
};
}
What's next
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2025-09-04 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eBefore using the JavaScript Fleet tracking library, ensure you have Fleet Engine set up and are familiar with it.\u003c/p\u003e\n"],["\u003cp\u003eFleet Engine requires JSON Web Tokens (JWTs) for API calls from low-trust environments like web browsers.\u003c/p\u003e\n"],["\u003cp\u003eYour backend server should be configured to issue JWTs to your Fleet tracking application for authentication and authorization with Fleet Engine.\u003c/p\u003e\n"],["\u003cp\u003eThe JavaScript Fleet tracking library utilizes an authorization token fetcher to request and manage JWTs, ensuring secure communication with Fleet Engine.\u003c/p\u003e\n"],["\u003cp\u003eAfter setting up authorization, you can proceed with tracking vehicles and viewing your fleet in real-time.\u003c/p\u003e\n"]]],["Fleet Engine authorization requires JSON Web Tokens (JWTs) for API calls from low-trust environments. Your backend server issues signed, encrypted JWTs to the client. Use Application Default Credentials and service accounts to authenticate. The JavaScript Fleet tracking library uses an authorization token fetcher to get a token from your server. The fetcher must return a token and its expiration time. The library requests a new token if no valid token exists, if it has expired, or if it is near expiring.\n"],null,["Before using the JavaScript fleet tracking library, make sure you are\nfamiliar with and have set up Fleet Engine. For details, see\n[Fleet Engine](/maps/documentation/mobility/fleet-engine).\n\nThis document shows how to enable authorization between the\nweb page app and Fleet Engine. Once your requests to Fleet Engine have\nbeen set up with the correct authorization tokens, you'll be ready to\ntrack a vehicle on a map.\n\nSet up authorization\n\nFleet Engine requires the use of **JSON Web Tokens** (JWTs) for API method calls\nfrom **low-trust environments**: smartphones and browsers.\n\nA JWT originates on your server, is signed, encrypted, and passed to the client\nfor subsequent server interactions until it expires or is no longer valid.\n\n**Key details**\n\n- Use [Application Default Credentials](https://google.aip.dev/auth/4110) to authenticate and authorize against Fleet Engine.\n- Use an appropriate service account to sign JWTs. See [Fleet Engine serviceaccount](/maps/documentation/mobility/fleet-engine/essentials/set-up-fleet/service-accounts#fleet_engine_service_account_roles) roles in **Fleet Engine Basics**.\n\nHow does authorization work?\n\nAuthorization with Fleet Engine data involves both server-side and client-side\nimplementation.\n\nServer-side authorization\n\nBefore you set up authentication and authorization in your Fleet tracking\napplication, your backend server must be able to issue JSON Web Tokens to your\nFleet tracking application for access to Fleet Engine. Your Fleet tracking application\nsends these JWTs with its requests so Fleet Engine recognizes the requests as\nauthenticated and authorized to access the data in the\nrequest. For instructions on server-side JWT implementation, see [Issue JSON Web\nTokens](/maps/documentation/mobility/fleet-engine/essentials/set-up-fleet/issue-jwt) under **Fleet Engine Essentials**.\nTo generate tokens from your server when implementing Fleet tracking, see the following:\n\n\u003cbr /\u003e\n\n- [General guidelines](/maps/documentation/mobility/fleet-engine/essentials/set-up-fleet/issue-jwt#general_guidelines) for issuing JSON Web Tokens, including sections for both on-demand trips and scheduled tasks\n- On-demand trips: [Example token for a backend server operation](/maps/documentation/mobility/fleet-engine/essentials/set-up-fleet/issue-jwt#example_token_for_a_backend_server_operation)\n- Scheduled tasks: [Example token to track all tasks and vehicles in the\n fleet](/maps/documentation/mobility/fleet-engine/essentials/set-up-fleet/issue-jwt#example_token_to_track_all_tasks_and_vehicles)\n\nClient-side authorization\n\nWhen you use the JavaScript Fleet tracking library, it requests a token from the server using an\nauthorization token fetcher. It does this when any of the following is true:\n\n- No valid token exists, such as when the SDK hasn't called the fetcher on a\n fresh page load, or when the fetcher hasn't returned with a token.\n\n- The token has expired.\n\n- The token is within one minute of expiring.\n\nOtherwise, the JavaScript Fleet tracking library uses the previously-issued, valid token and does not\ncall the fetcher.\n\nCreate an authorization token fetcher\n\nCreate your authorization token fetcher using these guidelines:\n\n- **The fetcher must return a data structure with two fields** , wrapped in a\n `Promise` as follows:\n\n - A string `token`.\n\n - A number `expiresInSeconds`. A token expires in this amount of time\n after fetching. The authentication token fetcher must pass the expiry\n time in seconds, from the time of fetching to the library as shown in\n the example.\n\n- **The fetcher should call a URL on your server** to retrieve a token. This\n URL--the `SERVER_TOKEN_URL`--depends on your backend implementation. The\n following example URL is for the [sample app backend on GitHub](https://github.com/googlemaps/last-mile-fleet-solution-samples/tree/main/backend):\n\n - `https://SERVER_URL/token/fleet_reader`\n\nExample - Create an authorization token fetcher\n\nThe following examples show how to create an authorization token fetcher: \n\nJavaScript \n\n async function authTokenFetcher(options) {\n // options is a record containing two keys called\n // serviceType and context. The developer should\n // generate the correct SERVER_TOKEN_URL and request\n // based on the values of these fields.\n const response = await fetch(SERVER_TOKEN_URL);\n if (!response.ok) {\n throw new Error(response.statusText);\n }\n const data = await response.json();\n return {\n token: data.Token,\n expiresInSeconds: data.ExpiresInSeconds\n };\n }\n\nTypeScript \n\n function authTokenFetcher(options: {\n serviceType: google.maps.journeySharing.FleetEngineServiceType,\n context: google.maps.journeySharing.AuthTokenContext,\n }): Promise\u003cgoogle.maps.journeySharing.AuthToken\u003e {\n // The developer should generate the correct\n // SERVER_TOKEN_URL based on options.\n const response = await fetch(SERVER_TOKEN_URL);\n if (!response.ok) {\n throw new Error(response.statusText);\n }\n const data = await response.json();\n return {\n token: data.token,\n expiresInSeconds: data.ExpiresInSeconds,\n };\n }\n\nWhat's next\n\n- [Track a vehicle](/maps/documentation/mobility/operations/fleet-tracking/follow)\n- [View a fleet](/maps/documentation/mobility/operations/fleet-tracking/view-fleet)"]]