Kaizen #191: Implementing "Login with Zoho" using Python SDK

Kaizen #191: Implementing "Login with Zoho" using Python SDK

      
Welcome back to another week of Kaizen!!

This week, we are diving into how to implement secure user authentication using Login with Zoho and integrate it with Zoho CRM through our Python SDK.

To ground this in a real-world scenario, we will look at how Zylker Academy, a training institute offering web design and development courses, uses an internal portal that connects directly to Zoho CRM. This setup allows course coordinators to manage student data without maintaining a separate backend database.

Zylker receives frequent student enquiries and uses Zoho CRM to manage all related information. Every course coordinator, academic advisor, and support staff member who needs access to student information is added as a user in Zoho CRM, with access permissions aligned to their role. Instead of using Zoho’s interface directly, Zylker’s team works through a custom internal web portal, tailored to their workflow. This portal connects directly to Zoho CRM, reading from and writing to it, but does not have its own database.

But before this portal can access any CRM data, it must authenticate itself securely. Every time a user opens the portal, they must log in with their Zoho account. Once authenticated, they will be granted access to the CRM modules and records they are authorized to work with. That is where Login with Zoho comes in.

What is "Login with Zoho"?

Login with Zoho is Zoho’s implementation of the OAuth 2.0 Authorization Code flow. It allows applications to authenticate users and access their Zoho CRM data without ever handling their passwords.
Instead of asking users for their Zoho credentials directly, the app redirects them to Zoho’s login screen. Here is how it works:
  1. The app redirects the user to Zoho’s login page.
  2. The user logs in and approves the requested permissions (scopes).
  3. Zoho sends back an authorization code.
  4. The backend exchanges this code for access and refresh tokens.
  5. These tokens are used to make authenticated API calls.
This flow ensures that users maintain full control over their data. They can revoke access at any time, and your application never handles or stores passwords. 
In Zylker’s case, every time a coordinator opens the portal, they are prompted to log in with their Zoho account. Once authenticated, they can immediately begin working with student records—all backed by Zoho CRM.

Use Case Implementation: Zylker’s Student Management Portal

To demonstrate how this login flow works, we have built a stripped-down version of Zylker's portal:
  • A front-end form to enter and view student data
  • A backend server that interacts with Zoho CRM via the Zoho CRM Python SDK
The application includes a simple form for capturing student details—name, college, course, email, and phone number. Submitted data is treated as a Lead in Zoho CRM.
The app allows users to:
  • Add new leads
  • View a list of all registered leads
  • Edit an existing lead’s information
  • Delete records if necessary
All actions go straight to Zoho CRM using its Python SDK. But before any of this can happen, the user must complete the login flow.

Sample Project Structure

Before going into the implementation details, let us briefly define the components of the project.

Frontend
The frontend is a simple static web interface built with HTML, CSS, and JavaScript. It runs in the browser and handles user interactions and triggers backend API calls. These are the main files:
  • index.html : Main UI for login, data entry, and record viewing.
  • script.js : Contains the client-side logic to trigger login, submit data, and render records.
  • redirect.html :  A minimal page used to capture the authorization code returned by Zoho after login.
The frontend is served using any static server (e.g., Live Server in VS Code) and runs on http://localhost:5501/ in our example. 
Download the files from here.
Configuration Notes:
  • In script.js, update the redirect_url value in the login request to match your actual domain or port if you’re not using localhost:5501.
  • Ensure the URL in the Zoho API Console matches this redirect URI and port.
Backend
The backend is a Python server that handles all interactions with Zoho CRM via the Python SDK. It includes:
  • server.py : A custom HTTP server that:
    • Generates the Zoho login URL
    • Exchanges the authorization code for tokens
    • Initializes the SDK
    • Exposes endpoints like /create, /get_records, /update, and /delete
  • record.py : Contains functions to create, fetch, update, and delete records in CRM modules like Leads. Each function uses the Zoho Python SDK methods to perform a specific operation.
This server runs on http://127.0.0.1:8085/ in our example. 

Download the files from here.
Configuration Notes:
  • In server.py, replace the client_id with your actual client ID from Zoho's API Console.
  • In record.py, replace the client_secret with your actual client secret.
  • If required, change the front-end server’s host and port in the run() function at the bottom of server.py:
    def run(server_class=HTTPServer, handler_class=SDKInitialize, port=xxxx):

Sample project flow

      

Step 1: Register the application with Zoho API console

To initiate the login process, you need to register your application on the Zoho API Console. This is a one-time setup that provides your app with a Client ID and Client Secret, both of which are required to authenticate users and exchange authorization codes for tokens.
To register your application:
We will be using these values in the backend script (server.py)  that handles token exchange.

NotesNOTE: To support users from multiple data centres, make sure to enable multi-DC support for your application. You can do this by going to your app’s settings in the Zoho API Console and turning on the Multi-DC option.

Step 2: Implementing the login flow

Here is a walkthrough of the flow implemented in the project:

1. Page loads and triggers login

When a user opens the portal, the frontend automatically initiates the login sequence. It first makes a call to the backend to retrieve the Zoho authorization URL. 

In index.html, this triggers getRecords() on page load:
  1. <body onload="getRecords();">
In script.js, getRecords() calls the login() function:
  1. async function getRecords() {
  2.     login();
  3. }
The login() function sends a request to the backend to get the Zoho OAuth authorization URL.

2. Backend builds login URL

The backend responds with an OAuth URL that includes:
  • Your client ID
  • Scopes like ZohoCRM.modules.ALL
  • The redirect URI
In server.py, under do_GET, the /login endpoint generates the OAuth URL:
  1.    if parsed_url.path == '/login':
  2.             redirect_url = query_params.get('redirect_url', [''])[0]
  3.             scope = "ZohoCRM.settings.fields.ALL,ZohoCRM.modules.ALL,ZohoCRM.users.READ,ZohoCRM.org.READ"
  4.             url = "https://accounts.zoho.com/oauth/v2/auth?scope=" + scope + "&client_id=" + self.client_id + \
  5.                   "&redirect_uri=" + redirect_url + "&response_type=code&access_type=offline"
  6.             self._set_headers()
  7.             # Send response
  8.             response = {"url": url, "redirect_url": redirect_url}
  9.  self.wfile.write(json.dumps(response).encode('utf-8'))
Once the frontend (script.js) receives the login URL, it opens it in a popup window.
  1. const response = await fetch('http://127.0.0.1:8085/login?redirect_url=http://127.0.0.1:5501/redirect.html');
  2. const data = await response.json();
  3. const popup = openCenteredPopup(data.url, "PopupWindow", 600, 400);
Here's an example of the Zoho OAuth authorization URL format:
      scope=ZohoCRM.modules.ALL&
      client_id=YOUR_CLIENT_ID&
      response_type=code&
      access_type=offline&
      redirect_uri=YOUR_REDIRECT_URI

3. User logs in on Zoho

The user logs in with their Zoho credentials and is prompted to approve the app's access. Once they approve, Zoho redirects them to the specified redirect URI along with an authorization code and location parameter. The location parameter indicates which data centre the user belongs to.

4. Frontend captures the authorization code

The redirect page, a minimal HTML file (redirect.html),  reads the URL parameters and stores them in localStorage, then closes the popup:
  1. function setAccessToken() {
  2.     var hashProps = getPropertiesFromURL();
  3.     if (hashProps) {
  4.         for (var key in hashProps) {
  5.             if (hashProps.hasOwnProperty(key)) {
  6.                 localStorage.setItem(key, hashProps[key]);
  7.             }
  8.         }
  9.     }
  10.     setTimeout(function () { window.close(); }, 0);
  11. }

5. Token exchange and SDK initialization

Once the popup window is closed, the main window retrieves the authorization code and location and sends them to the backend’s /initialize endpoint.
In script.js:
  1. var code = localStorage.getItem("code");
  2. var location = localStorage.getItem("location");
  3. initialize(code, location, data.redirect_url);
  4. .
  5. .
  6. async function initialize(code, location, redirect_url) {
  7.     const response = await fetch('http://127.0.0.1:8085/initialize?code=' + code + '&location=' + location + '&redirect_url=' + redirect_url);
  8. }
In server.py, the /initialize endpoint handles SDK initialization:
  1. elif parsed_url.path == '/initialize':
  2.     code = query_params.get('code', [''])[0]
  3.     location = query_params.get('location', [''])[0]
  4.     redirect_url = query_params.get('redirect_url', [''])[0]
  5.     LeadsRecords().init(self.client_id, code, location, redirect_url)
In record.py, the SDK is initialized and tokens are stored.
  1. token = OAuthToken(client_id=client_id,
  2.                    client_secret=client_secret,
  3.                    grant_token=code,
  4.                    redirect_url=redirect_url)
  5. Initializer.initialize(environment=environment,
  6.                        token=token,
  7.                        logger=logger,
  8.                        store=store)  # FilePersistence or custom store
This exchanges the authorization code for:
  • An access token (valid for one hour)
  • A refresh token (used to get new access tokens)
These tokens are saved in a local file (sdk_tokens.json). This is configured using Zoho’s FilePersistence class during SDK initialization 

How are tokens linked to users?

The SDK maps each access and refresh token pair to a unique user-organization combination. This means tokens generated for different organizations by the same user are stored separately. Likewise, if a user generates new tokens for the same organization, the SDK updates the existing tokens instead of creating duplicates. This ensures that API calls always use the correct tokens tied to the authenticated user and their organization. 

To enable this mapping, the SDK retrieves the user and organization information in the background. This requires the appropriate scopes to be included during authentication, ZohoCRM.users.READ and ZohoCRM.org.READ. Without these scopes, the SDK cannot identify the user-org combination correctly, which can lead to multiple token entries for the same user. That is why, in our sample project, we have included these scopes explicitly in the server.py file during the SDK initialization.

Once the SDK is initialized, the user is logged in, and the app can begin making CRM API calls on their behalf.


Step 3: Accessing Zoho CRM

Once the user is authenticated and the Zoho SDK is initialized on the backend, the frontend can call custom backend endpoints like /create or /get_records. These endpoints use the authenticated SDK instance to make CRM API calls on behalf of the user.
  • GET /get_records?module=Leads : View all students
  • POST /create?module=Leads : Add new student
  • PUT /update?module=Leads&id=... : Edit existing entry
  • DELETE /delete?module=Leads&id=... : Remove existing entry

Deploying the sample project

To run this application, you will need two components:
  1. A frontend server to serve your HTML files (index.html, script.js, redirect.html). This can be done using any static web server (e.g., Live Server in VS Code).
  2. A Python backend server that handles login, token storage, and CRM API communication. You can run it using:
    python server.py
In the given example, both servers communicate over localhost. You should set your redirect URI accordingly when registering your app in the Zoho console.

Conclusion

Login with Zoho is a secure, OAuth-based mechanism that allows users to authorize your application to access their Zoho CRM data. In this example, we built a real-world use case, a student portal for Zylker Academy, that authenticates users and interacts with CRM directly using the Zoho CRM Python SDK.
By walking through the entire flow, you now understand:
  • Why OAuth is essential for secure CRM access
  • How to register an application in Zoho
  • What the login and token exchange flow looks like
  • How to implement "Login with Zoho" in your applications

What is next?

In this project, we have used a simple file persistence method to store the token files. But in a real world scenario, this may not always meet your business requirements. In next week's Kaizen, we will implement custom token persistence instead of file persistence in the current project. We will explain how to implement this using SQLite, In-Memory and List DBs. With that, you will be equipped to implement a persistence method that fits your application architecture and deployment environment.

We hope that you found this useful. If you have any queries, let us know the comments below, or send an email to support@zohocrm.com. As always, we would love to hear from you!!

Stay tuned for next week's Kaizen : Implementing Custom Token Persistence 


Download Links:
Further Reading:

    • Sticky Posts

    • 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

    • Kaizen #152 - Client Script Support for the new Canvas Record Forms

      Hello everyone! Have you ever wanted to trigger actions on click of a canvas button, icon, or text mandatory forms in Create/Edit and Clone Pages? Have you ever wanted to control how elements behave on the new Canvas Record Forms? This can be achieved

    • Recent Topics

    • Can i connect 2 instagram accounts to 1 brand?

      Can i connect 2 instagram accounts to 1 brand? Or Do i need to create 2 brands for that? also under what subscription package will this apply?

    • Zoho Forms - Improved Sub-Forms

      Hi Forms team, I'm helping a client move from JotForms to Zoho Forms and I've found another opportunity for improvement. In the below screenshot, JotForm left and Zoho Forms right. The Zoho Forms Sub-Form is quite a poor visually. There is no way to make

    • What's New in Zoho Billing | Q3 2025

      Hello everyone, We are excited to share the latest set of updates and enhancements made to Zoho Billing in Q3 2025. From the latest GST updates to multi-level discounting, Zia-powered report summaries, and customizable web forms, these updates are designed

    • How to Delete Personal Account Linked with My Mobile Number in past or by someone else

      How to Delete Account Created with My Mobile Number in past or by someone else This is creating issues in making or sync with my credentials mobile and email address..

    • WhatsApp Business Calling API

      Dear Zoho SalesIQ Team, I would like to request a feature that allows users to call WhatsApp numbers directly via Zoho SalesIQ. This integration would enable sending and receiving calls to and from WhatsApp numbers over the internet, without the need

    • Does Zoho Learn integrate with Zoho Connect,People,Workdrive,Project,Desk?

      Can we propose Zoho LEarn as a centralised Knowledge Portal tool that can get synched with the other Zoho products and serve as a central Knowledge repository?

    • Marketer's Space - Going beyond basics: Smarter ecommerce marketing with Zoho Campaigns

      Hello Marketers, Welcome back to this week's Marketer's Space. In the last post, we discussed the basics of email marketing and how to get started with email marketing in ecommerce. In this part, we'll dive much deeper into some other advanced features

    • Connecting two modules - phone number

      Hi, I’d like some guidance on setting up an automation in Zoho CRM that links records between the Leads module and a custom module called Customer_Records whenever the phone numbers match. Here’s what I’m trying to achieve: When a new Lead is created

    • Zoho Marketing Automation 2.0 - Landing Page function not working

      Dear Zoho Team, I am working on implementing Zoho Marketing Automation 2.0, and am now looking into the section "Lead Generation". If I open the "Landing Pages" section, I immediately get an Error code: Error: internal error occurred. Can you help me

    • Unable to use Sign "You have entereed some invalid characters"

      Unable to use Sign "You have entered some invalid characters" I do not see any invalid characters. The text in "Leave a Note" is plain text which I entered directly into the field. See attached screenshot

    • cannot login from outlook on mobile

      Hi there,   I tried to set up my email accounts on my iphone using outlook, but it always return email address and password error. Please find the attachment for the screenshot. I am pretty sure that I typed in the correct email address and password and the imap has been enabled from zoho admin account. I can configure the email address on iphone default mail service as well as outlook on pc, the problem only occurs on the outlook app on mobile. I do need to use this app instead of the iphone default

    • Elevate your CX delivery using CommandCenter 2.0: Simplified builder; seamless orchestration

      Most businesses want to create memorable customer experiences—but they often find it hard to keep them smooth, especially as they grow. To achieve a state of flow across their processes, teams often stitch together a series of automations using Workflow

    • Messages not displayed from personal LinkedIn profile

      Hello. I connected both our company profile and my personal profile to Zoho social. I do see all messages from our company page but none from my private page. not even the profile is being added on top to to switch between company or private profile,

    • "Performed changes in the query is not allowed due to following reason" when adding columns or reordering data

      I'm trying to make changes to a query but every time i try to save it i get this error message. I'm not touching the data it's flagging. All I've tried to do is reorder a couple of fields and add a new one. Why won't it let me do this? It's a core query

    • Onboard new users easily with native screen recording in Zoho Projects Plus

      Communication involving both visual and audio elements tends to capture more interest among the audience. Whenever we onboard new employees to the organization, the task of engaging them in the induction sessions, and keeping the spark going in their

    • Request to Add Support for PDF Templates and More Flexibility in Email Editor

      Hi Zoho Campaigns Team, I hope you're doing well. I wanted to share some feedback and request a few improvements in the Email Template feature of Zoho Campaigns. Right now, we can create email templates using the HTML editor, which is helpful. But we’re

    • Can you stop Custom View Cadences from un-enrolling leads?

      I'm testing Cadences for lead nurture. I have set un-enroll properties to trigger on email bounce/unsubscribe, and do NOT have a view criteria un-enroll trigger. However, help documents say that emails are automatically un-enrolled from a Cadence when

    • Zoho Desk Android and iOS app update: Agent detail overview

      Hello everyone! We’ve introduced agent detail overview on the Zoho Desk Android and iOS app update. With this feature, you can get a complete view of agent’s tickets, response times, logged hours (for both tickets and activities), customer happiness ratings

    • Blog Widget: Show recent blog posts on my homepage

      Hey there I am using the Zoho Sites Blog feature. On my homepage, on the bottom I'd like to have a featured content section where I show some of my blog posts (selected, most recent, filtered by category and so on...). It would be nice to have a blog

    • How to iterate through excel data using zoho rpa

      I wanted to iterate or loop through excel data ( datatable). How can i do that

    • Zoho Commerce

      Hi, I have zoho one and use Zoho Books. I am very interested in Zoho Commerce , especially with how all is integrated but have a question. I do not want my store to show prices for customers that are not log in. Is there a way to hide the prices if not

    • Mass (Pull back) (Close WOs) (Close APs)

      Hi develop team. Just idea because Zoho FSM is great but its too manual. we have a lot of task to do every day and the system needs to have more features to automatic our tasks. I need to close several WOs, APs and Pull Back per day. Please we need mass

    • Customising Zohidesk portal default widgets

      Hello, I'm wondering how could I customise the default widgets such as "popular topics", "popular articles" using CSS or to make the tiles at the bottom match the ones that I made in the picture attached. I have made some custom widgets and edited them

    • If there’s a batch at the end, the ‘mark as inactive’ function doesn’t work.

      when my batch has a date to batch end and I "mark as inactive" he batch does not obey the status and reactivates the batch.

    • Seamless multilingual messaging and tone control in Zia IM Composer

      Hello everyone! Managing customer conversations across multiple languages can be time-consuming. Using Zia in the Instant Messaging (IM) Composer helps you overcome this by providing tools to translate content, adjust your tone, and refine your messages

    • Advanced Deluge help needed with custom function and COQL limits

      I have a scheduled function that takes a snapshot of specific metrics and saves them to a custom module. However I'm struggling with the limits of COQL. I attach my full code, but an example of the issues I'm having is that it's erroring with a 'Limit

    • Tip of the Week - Conditional Formatting Chart

      Conditional formatting allows you to highlight your data series based on a pattern or a trend in your data. This makes it easy for you to identify when your data reaches certain values or when it deviates from the trend.  Zoho Analytics allows you to

    • Zoho Campaign says "null"

      Here is what I did: 1. Created a list in CRM, made a form to fill information in the list. - This is working fine. 2. Created a flow to connect CRM (chose a the list) and want to add an event in Google Calendar. (Calendar is connected). Problem 1 - When

    • Zoho Learn - AI Translate

      Hi Learn team, I had a situation today where I was providing training to a client team and I had written articles into their Zoho Learn to support their learning. I realised that one of the team members was a non-native English speaker and they were struggling

    • Power of Automation :: Auto-Sync Custom Date Field Between Related Tasks via Blueprint Transition

      Hello Everyone, A custom function is a software code that can be used to automate a process and this allows you to automate a notification, call a webhook, or perform logic immediately after a workflow rule is triggered. This feature helps to automate

    • Introducing auto-upgrade in Zoho LandingPage

      Hi everyone, We’re excited to share an upcoming update to help you get the most out of your landing pages — the auto-upgrade option, launching on October 22, 2025. Your landing pages are designed to bring in leads, and we want to make sure you never miss

    • Webhook Authentication Key

      As Google Ads' lead form extension does not integrate with Zoho CRM at the moment other than Zapier. I want to use the Zoho Flow webhook feature to send leads to Zoho CRM. Meaning creating a flow in Zoho Flow that triggers based on Webhook and then webhook

    • Workdrive comment links stopped working.

      I have marked a PDF file with 95 comments, they have worked for a while. When i clicked on them they brought me to the correct page and showed me the outline that i had drew on the plans. The comments included the page number of the outline, but now it

    • How to Bulk-Update Sales Orders in CRM

      Hi - I need to bulk update existing sales orders with dates from our ERP of when the sales orders were created. I made a date field on the Sales Order module where I want to insert that data. I can't Mass Update because I am not updating the fields to

    • Zoho ToDo in Cliq

      Our organization utilizes Zoho ToDo in the Zoho Mail Desktop app. Is there a way for these to show up in Cliq Desktop app as well?

    • 【Zoho CRM】サンドボックス機能のアップデート：カスタムビューが利用可能になりました。

      ユーザーの皆さま、こんにちは。コミュニティチームの中野です。 今回は「Zoho CRM アップデート情報」の中から、サンドボックス機能のアップデートをご紹介します。 目次 1. カスタムビューとは 2. 今回の機能アップデートについて 1. カスタムビューとは カスタムビューは、ユーザーが設定した条件に基づいてデータをフィルタリング・整理し、 重要な情報へ効率的にアクセスできるようにする機能です。 「過去15日間の見込み客」や「受注間近の商談」、「特定の優先度レベルが設定された案件」など 条件を指定してわずか数クリックで設定できます。

    • Changing an agents email address

      How do you change an agent's email address? I keep getting a red circle even though I am an admin. And on one of my agents he has two email addresses? How is that possible?

    • Zoho CRM - Potentials Tab

      Hi! When I create a Deal (Potentials tab) the header looks like this: After a refresh on the page it looks like this: What should I do so that it is displayed like in the second pic without refresh? Also I have a user that as of recently, cannot see this

    • Unable to create embed code for resource of workdrive using API

      Hello Team, I am trying to create embed code for a resource using workdrive api in powershell, however facing some issues with injecting data in body. Followed Doc: https://workdrive.zoho.com/apidocs/v1/filefoldersharing/shareeveryone Please help, below

    • Feature Request - Insert URL Links in Folders

      I would love to see the ability to create simple URL links with titles in WorkDrive. or perhaps a WorkDrive extension to allow it. Example use case: A team is working on a project and there is project folder in WordDrive. The team uses LucidChart to create

    • Next Page