Kaizen #116 - Client Types in Zoho API Console

Hello everyone!

Welcome back to another post in the Kaizen series!

This week, we will discuss different client types available in Zoho API Console, and when to use each.

When you register an app in Zoho API Console, you typically choose a client type based on how your application interacts with Zoho services.

Let us discuss the available client types and how authorization is handled for each.

Available client types

1. Server-based
   
2. Client-based
   
3. Self client
   
4. Non-browser-based
   
5. Mobile-based

1. Server-based

If you have a web-based application that runs on a dedicated HTTP server and interacts with Zoho services by calling Zoho APIs via that server, you must register your app with this client type.

This client type is for applications that redirect the users to another URL on a web browser to authorize themselves, where they give consent to your application to use their data.

In other words, you must use this client type when you have a front-end web UI and require user intervention before your app can access user data via the dedicated server.

Consider that you are developing a web-based custom application. Users authorize that app via browser to allow their Zoho CRM data to be accessed and used by that application.

During the registration process in Zoho API Console, you would choose the "Web-based" client type.

OAuth 2.0 would be used for user authentication, allowing your app to securely access and interact with Zoho CRM data on behalf of the users.

Here is a gist of what happens:

1. Users visit your website where you have the Login with Zoho button.
   
2. When a user clicks it, that user will be redirected to accounts.zoho.com with the details of your app such as client ID, scope, redirect uri, access type as the URL parameters.
   
3. Your app must make an API call to Zoho Accounts with the client ID, scope, redirect uri, and access type. Users are shown the data that your application wants to use.
   
4. When users give their consent, Zoho redirects them back to your app.This will be the "Redirect URL" you give while registering your app.
   
5. The redirect URL will have the authorization code(grant token) as one of the parameters, along with the location(user's domain).
   
6. Your app must then make API calls from your web server to Zoho Accounts to generate access and refresh tokens with the generated grant token.
   
7. You must store these tokens in your DB to access that user's data in Zoho CRM. While making API calls, you must send this access token in the header.
   
8. Your app must also have the logic to regenerate access tokens from refresh tokens when the access token expires.
   

Note that your app must take care of storing user's details like email, organization ID, and tokens.

The following image shows the protocol flow.

You can use any of our server-side SDKs to simplify this process.

When you use our SDK, all you have to do is, generate the grant token and initialize the SDK with the client details and this token. The SDK takes care of access token generation, refreshing it, and token storage.

Refer to these older Kaizen posts on Integrating a third-party app using Java SDK and Java SDK for Self Client.

For more details, you can refer to the Accounts guide and CRM help doc.

2. Client-based applications

This client type is for applications that do not have a server and run exclusively on a web browser.

This is also called the Implicit flow as your app makes API calls to Zoho only when users are using your app.

This type of application loads data dynamically on the webpage, and accesses Zoho CRM data by making API calls via Javascript.

Consider the same example where there is a Login with Zoho button on your webpage.

Here is a gist of what happens when a user clicks it.

1. Your app redirects the user to Zoho Accounts.
   
2. Your app makes the authorization request with the client ID, redirect uri, scope, and response type as token.
   
3. The user is shown the data that your webpage would use.
   
4. When the user gives consent, Zoho Accounts sends the access token to the redirect uri as a parameter, along with the expiry time and the location of user's data in Zoho's accounts server.
   
5. You can include the "email" in your scope parameter in the access token request to get user's information. The response will have a parameter called id_token that will be in the header.payload.signature format. You need to decrypt the payload section of the parameter using the base-64 decryption algorithm to get user information.
   
6. Your app must then make API calls to Zoho with this access token to fetch data.
   
7. When the access token expires, your app must take care of regeneration and storage.
   

As the API calls are made from your domain to a different domain(zohoapis.com), for security reasons, the browser will throw the CORS error. So, your domain will be registered while registering your app, and Zoho will know to allow the API calls made from that domain.

As the tokens are available on the browser itself, we recommend handling them with care.

When you use our client-side JS SDK, it automatically generates a new access token upon expiry.

3. Self Client Applications

When your application does not have a redirect URL or a UI, but performs only a backend job, and does not need user intervention, then you must choose this client type.

A self client is often used when the application and Zoho services are operated by the same entity, and you want to enable secure communication between them. For example, you have an internal reporting tool and integrate it with Zoho Analytics. In this case, both the tool and Zoho Analytics are operated by the same entity.

Similarly, consider that you have a legacy product management system and want to perform data sync between Zoho CRM and the system, then you must use the self client.

Here is a gist of what happens.

1. You register your app as self client in Zoho API Console.
   
2. You will get the client details such as ID and secret.
   
3. You provide the scopes required for your app to access CRM data.
   
4. You will receive the grant token.
   
5. Your app must then make API calls to Zoho Accounts to generate access and refresh tokens.
   
6. Your app can then use this access token to make API calls to Zoho CRM and use data.
   

You can refer to our older Kaizen post on this topic for more details.

Note that self client apps can also use any of our server-side SDKs. As already said, the SDK takes care of access and refresh token generation, refreshing the access token, and token storage.

4. Non-browser applications

This client type is for devices that do not have a user agent such a web browser. A TV, for instance.

Let us consider an example involving a smart TV application that integrates with Zoho ShowTime. In this scenario, the smart TV application acts as a non-browser client.

Here is how authentication is handled:

1. You must register your smart TV app in Zoho API Console with the type "Non-browser application".
   
2. Users install a dedicated Zoho ShowTime application on their smart TVs.
   
3. When users launch the Zoho ShowTime application on their smart TV, they are prompted to authenticate with their Zoho ShowTime account.
   
4. When they successfully authenticate, Zoho Accounts sends the grant token to your app, along with the user-code, device-code and verification URL,The user must go to this verification URL on a browser and enter the user-code to grant permission to the app.
   
5. Meanwhile, your app must poll the accounts server using the grant token to check if the token has been received.
   
6. When the user enters the user code, Zoho Accounts sends the access token to your app.
   
7. Your app can then use the access token to make API calls to Zoho. Your app must take care of token storage and renewals.
   

Here is the protocol flow. For more details, refer to this doc.

5. Mobile-based applications

You must use this client type when you have developed an app exclusively for mobile devices. The protocol flow is similar to server-based application where a browser session is required for the users to authenticate.

Similar to server-side apps, mobile apps also need to handle redirection, token generation and storage.

If you use any of our Mobile SDKs, the SDK itself handles token generation and storage.

We hope you found this post useful. Let us know your thoughts in the Comment section or write to us at support@zohocrm.com.

Cheers!

• Topic Participants

• Shylaja S

  

• Piyush Dwivedi

• Ishwarya SG

  

• Onur Gulay - Smile Center Turkey®

  

• Sunderjan Siddharth

  

• Sticky Posts

• Kaizen #198: Using Client Script for Custom Validation in Blueprint

  Nearing 200th Kaizen Post – 1 More to the Big Two-Oh-Oh! Do you have any questions, suggestions, or topics you would like us to cover in future posts? Your insights and suggestions help us shape future content and make this series better for everyone.

• Kaizen #226: Using ZRC in Client Script

  Hello everyone! Welcome to another week of Kaizen. In today's post, lets see what is ZRC (Zoho Request Client) and how we can use ZRC methods in Client Script to get inputs from a Salesperson and update the Lead status with a single button click. In this

• Kaizen #222 - Client Script Support for Notes Related List

  Hello everyone! Welcome to another week of Kaizen. The final Kaizen post of the year 2025 is here! With the new Client Script support for the Notes Related List, you can validate, enrich, and manage notes across modules. In this post, we’ll explore how

• Kaizen #217 - Actions APIs : Tasks

  Welcome to another week of Kaizen! In last week's post we discussed Email Notifications APIs which act as the link between your Workflow automations and you. We have discussed how Zylker Cloud Services uses Email Notifications API in their custom dashboard.

• Kaizen #216 - Actions APIs : Email Notifications

  Welcome to another week of Kaizen! For the last three weeks, we have been discussing Zylker's workflows. We successfully updated a dormant workflow, built a new one from the ground up and more. But our work is not finished—these automated processes are

• Recent Topics

• Emails not being received by @hotmail.com, @outlook.com and a few others

  When I try to send emails from zoho mail to people with email addresses ending @outlook.com and @hotmail.com (and a few others), I get a 'delayed' automatic email and then a few hours later, an 'undelivered' automatic email. This has started a few months

• scroll bar for far left of screen

  I am unable to even see the scroll bar to the right of "inbox" etc on the left; it is stuck at "streams" and I can't get to inbox or anything else. It would help if it could be made a lighter color as the black or dark grey can't bee seen.

• OUt of office every friday

  Hi, I tryed to configure my out of office, because i'm not working or emailing on fridays. But when i select only friday as unavailable day, the out of office still sets for the whole week. What am I doing wrong?

• Signature line

  How do I set signature line in email

• Zoho email

  I cannot send email to mail.ru

• 【参加無料】東京 Zoho ユーザ交流会 NEXUS ー CRMで始めるマーケティング事例 / AI活用法(Zia Agents)

  ユーザーの皆さま、こんにちは。コミュニティチームの藤澤です。 3月27日(金)に東京、新橋で東京 Zoho ユーザー交流会 NEXUS を開催します！ 昨年度までより、さらにパワーアップして戻ってきました！ ユーザー活用事例は、2人のユーザーさんからお話しいただきます。Zoho サービスの活用の幅を広げたい方や、他のユーザーの利用法を気軽に知りたい方など、多くの方にとって学びのあるセッションになること間違いなしです✨ また今年は、これまで以上に、AI機能にも焦点を当てて行く予定です。 初回として、Zoho社員からZoho

• Issue Exporting Data – CSRF Token Invalid Error

  Dear Zoho Team, We are experiencing an issue when exporting data from our Analytics workspace. Whenever we attempt to export data from our analytical pool, the system displays the following alert message: Alert Message: The CSRF token is invalid. It could

• Deluge Learning Series – Client functions in Deluge | January 2026

  We’re excited to kick-start the first session of the 2026 Deluge Learning Series (DLS) with Client functions in Deluge. For those who are new to DLS, here’s a quick overview of what the series is all about: The Deluge Learning Series takes place on the

• Zoho Mail 505 error I can not send email

  Hi, I’m having issues sending emails from my custom domain email address. When I send emails to Outlook addresses, I receive an “Undeliverable 505” error. However, emails send and receive correctly when I use Gmail. This is important for my business,

• Multiple MFA Methods

  With SMS-based MFA methods being discontinued, there is now no way to have mutliple MFA methods. I'd like to add my zoho account on two seperate phones using the Google Authenticator app. In the https://accounts.zoho.com/home#multiTFA/modes you can only

• Reuse Standalone Function

  I noticed that there's a missing information in documentation to reuse a standalone function and it is because the parameters require an argument. Here is my code and it is working. response = invokeurl [ url: "https://people.zoho.com/api/v3/function/sample/execute"

• Domain renewals

  Need to know how hoe to renew the domain

• MX shopify problem

  hello, i added all MX values in my shopify DNS - it shows those values on the shopify panel + your toolkit. I tried to send some email and it works, however on my gmail it says they cant verify this email. When i try to answer into my domain's email -

• Best Way to Manage Email Notifications While Running a Strategy Website

  I am currently managing a content-based website, and I use Zoho Mail for handling contact forms, user queries, and collaboration emails. One challenge I am facing is organizing incoming emails efficiently, especially when messages come from different

• What is the maximum email domains ?

  I help manage about 20 associations and I'm looking for a way to centralize them in one place. Does Zoho Mail pro or enterprise support 20-30 domains for 3-5 users each?

• Add to Workdrive filter

  I'm trying to create a filter that will upload attachments in emails and the e-mail body to a folder in workdrive. I am able to do one or the other (attachment, or e-mail content), but not both. I first tried it using the "Email (EML) + attachment" option.

• Forgot my admin Panel Id and password

  Sir, I have an account , where a domain mycityestate.in is added for Zoho email , now it is hard for me to manage email because i have forgotten the Email account and password registered with Admin Panel of Zoho. Just need email name which is registered

• MCP no longer works with Claude

  Anyone else notice Zoho MCP no longer works with Claude? I'm unable to turn this on in the claude chat. When I try to toggle it on, it just does nothing at all. I've tried in incognito, new browsers, etc. - nothing seems to work.

• Knowledgebase SEO

  We have a custom-domain mapped help center that is not restricted via login. I have some questions: a) will a robots.txt file still allow us to control indexing? b) do we have the ability to edit the sitemap? c) do category URLs get indexed by search

• Problem with CRM Connection not Refreshing Token

  I've setup a connection with Zoom in the CRM. I'm using this connection to automate some registrations, so my team doesn't have to manually create them in both the CRM and Zoom. Connection works great in my function until the token expires. It does not refresh and I have to manually revoke the connection and connect it again. I've chatted with Zoho about this and after emailing me that it couldn't be done I asked for specifics on why and they responded. "The connection is CRM is not a feature to

• New Features: Repeat Last Action, Insert Cut/Copied Rows/Columns and Hyperlink

  You might have noticed the constant updates to Zoho Sheet of late. Here are 3 more features that have been added to Zoho Sheet recently: F4 - Repeat Last Action Insert Cut/Copied Rows and Columns Insert Hyperlink Here is a screen cast demonstrating each of these features. Read further below to learn more about these new features. F4 - Repeat Last Action: You can now repeat the last action you made on your spreadsheet by using the keyboard shortcut, F4. It is quite handy and helps you get your work

• Need help getting my mail on iPhone and Tablet

  I need to access my Zoho mail via the iPhone Mail app. I have entered the login name, password and the incoming and outgoing servers, which my Mail Settings page says are imappro.zoho.com and smtppro.zoho.com. The iPhone keeps saying it cannot authenticate.

• Add an background image to an email template in CRM

  Hi all, We wants to put an background image behind all our email templates. Is there a way to import this thru html. If i put the option background image in <body style="background-image:...</body> and i look to the preview it shows our background, but

• Is there a way to show contact emails in the Account?

  I know I can see the emails I have sent and received on a Contact detail view, but I want to be able to see all the emails that have been sent and received between all an Accounts Contacts on the Account Detail view. That way when I see the Account detail

• How do I bulk archive my projects in ZOHO projects

  Hi, I want to archive 50 Projects in one go. Can you please help me out , How can I do this? Thanks kapil

• Copy contents of File Upload Field into Workdrive

  Hello, I have set up our CRM so that a Workdrive folder is automatically created for each Deal via workflow, this adds the id of the folder into a dedicated field. We also have a field on each Deal called 'Approved Layout', which is a file upload field.

• Deleting a memorized email address

  How can I delete a memorized email address? Even though the address has been deleted from Contacts, Zoho mail still auto suggests the address when typing it into the TO field. Thanks!

• ZeptoMail API

  Hello Since today, we experience issues with the ZeptoMail API. When trying to send e-mails using: https://api.zeptomail.eu/v1.1/email we receive the error: (503) Site unavailable due to a traffic surge. Please try again shortly. I kindly ask you to identify

• 553 Relaying disallowed. Invalid Domain - gzkcompany.ro

  Hi there, Can you please assist me in getting the right domain settings? I just renewed my domain subscription, after expired and i got error: 553 Relaying disallowed. Invalid Domain - gzkcompany.ro Zoho mail can receive emails, but its impossible to

• Not able to receive emails for a while

  I am not able to receive emails for a while now.

• Confirmation requested: eligibility and process to downgrade to Forever Free — tenant bigbanghawking.com

  Thank you for your reply. I am testing Zoho Mail from Brazil with the tenant bigbanghawking.com (endpoint: mail.zoho.com) and we are currently on the Premium trial that expires 21/01/2026. Before deciding whether to pay or cancel, I need written confirmation

• Zoho API v2.0 - get ALL users from ALL projects

  Hello,        I've been trying to work on an automatization project lately and I find it difficult to work with this strict structure. To be more explicit, if i would like to get all users participating in a project i would need to get all projects first.       Same thing with projects. If i want to get all projects, I would need to get all portals first.        The problem with this aproach is that it consumes a lot of time and resources.             I want to ask if there is another way of getting

• الموقع لا يقوم بالسداد

  السلام عليكم ورحمة الله وبركاته وبعد من أمس وانا احاول السداد للدومين YELLOWLIGHT ولا اتمكن من السداد اقوم بتعبئة جميع البيانات ولكن دون جدوى يطلع لى حدث خطأ ما

• New in Office Integrator: Enhanced document navigation with captions and cross references

  Hi users, We're pleased to introduce captions, table of tables and figures, and cross-references in the document editor in Zoho Office Integrator. This allows you to structure documents efficiently and simplify document navigation for your readers from

• Where Do I set 24h time format in Cliq?

  Where Do I set 24h time format? Thanks

• 🎉 ¡Seguimos trayendo novedades a Español Zoho Community! 🎉 Confirmada la agenda y ubicación para los Workshops Certificados

  Si todavía no te has hecho con tu entrada para nuestros Workshops Certificados del próximo 26 y 27 de marzo o, por el contrario, estabas esperando que confirmáramos dónde los celebraremos, ¡este post es para ti! 📍¿Dónde nos vemos?📍 Nuestros Workshops

• User is already present in another account error in assigning users to marketing automation

  Hello everyone Greeting, I had a problem in assigning user in marketing automation, when I try to add it I see this error: (User is already present in another account error) what should I do?

• How do I get complete email addresses to show?

  I opened a free personal Zoho email account and am concerned that when I enter an email address in the "To", "CC", fields, it changes to a simple first name. This might work well for most people however I do need to see the actual email addresses showing

• What's New in Zoho POS - January 2026

  Hello everyone, Welcome to Zoho POS’s monthly updates, where we share our latest feature updates, enhancements, events, and more. Let’s take a look at how January went. Sort and resolve conflicts Conflicts are issues that may arise when registers and

• Outlook is blocking incoming mail

  Outlook is blocking all emails sent from the Zoho server. ERROR CODE :550 - 5.7.1 Unfortunately, messages from [136.143.169.51] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). It looks

• Next Page