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

    • Bigin, more powerful than ever on iOS 26, iPadOS 26, macOS Tahoe, and watchOS 26.

      Hot on the heels of Apple’s latest OS updates, we’ve rolled out several enhancements and features designed to help you get the most from your Apple devices. Enjoy a refined user experience with smoother navigation and a more content-focused Liquid Glass

    • Notes badge as a quick action in the list view

      Hello all, We are introducing the Notes badge in the list view of all modules as a quick action you can perform for each record, in addition to the existing Activity badge. With this enhancement, users will have quick visibility into the notes associated

    • Claude + MCP Server + Zoho CRM Integration – AI-Powered Sales Automation

      Hello Zoho Community 👋 I’m excited to share a recent integration we’ve worked on at OfficehubTech: ✅ Claude + MCP Server + Zoho CRM This integration connects Zoho CRM with Claude AI through our custom MCP Server, enabling intelligent AI-driven responses

    • Automatic Matching from Bank Statements / Feeds

      Is it possible to have transactions from a feed or bank statement automatically match when certain criteria are met? My use case, which is pretty broadly applicable, is e-commerce transactions for merchant services accounts (clearing accounts). In these

    • How to filter Packages in zoho inventory api

      Hi Team, I want to perform some tasks in a schedular on the packages which are in "Shipped" state. I tried to use filter_by in my api call but in return I get response as {"code":-1,"message":"Given filter is not configured"} My Api request is as follows

    • CRM

      Is anyone else experiencing this issue? Our company is not moving out of using Gmail's web app. It just has more features and is a better email program than Zoho Mail. Gmail has an extension (Zoho CRM for Gmail) that we're using but we've found some serious

    • Automate pushing Zoho CRM backups into Zoho WorkDrive

      Through our Zoho One subscription we have both Zoho CRM and Zoho WorkDrive. We have regular backups setup in Zoho CRM. Once the backup is created, we are notified. Since we want to keep these backups for more than 7 days, we manually download them. They

    • Syncing with Google calendar, Tasks and Events

      Is it possible to sync Zoho CRM calendar, task and events with Google Calendar's tasks and events. With the increasing adoption by many major tool suppliers to sync seamlessly with Google's offerings (for instance I use the excellent Any.do task planning

    • IMAP mail after specify date

      Hi My customer's mail server is on premise and mail storage is very huge. So It never finish sync. and finally stop sync. Cloud CRM have a option like zoho mail sync mail after some date.

    • How can i view "Child" Accounts?

      It can be very useful in our field of business to know the parent-child account relationship. However, there seems to be a shortcoming in the parent account view: no child account list. How can we view the child accounts per each account?

    • Ability to assign Invoice Ownership through Deluge in FSM

      Hi, As part of our process, when a service appointment is completed, we automated the creation of the invoice based on a specific business logic using Deluge. When we do that, the "Owner" of the invoice in Zoho FSM is defaulted to the SuperAdmin. This

    • Easily perform calculations using dates with the new DATEDIF function

      Hey Zoho Writer users! We've enhanced Zoho Writer's formula capabilities with the new DATEDIF function. This allows you to calculate the difference between dates in days, months, and years. Function syntax: =DATEDIF(start_date, end_date, unit) Inputs:

    • Adding Comments Using Workflows - How to Change User Attributed

      We have worklflows in Desk where a comment is added to a ticket based on certain criteria. It seems that the comment added is always attributed to the user who last edited the workflow. This does not make sense for us because: - It's misleading to other

    • Add Attachment Support to Zoho Flow Mailhook / Email Trigger Module

      Dear Zoho Support Team, We hope you are well. We would like to kindly request a feature enhancement for the Mailhook module in Zoho Flow. Currently, the email trigger in Zoho Flow provides access to the message body, subject, from address, and to address,

    • Conect chat of salesiq with zoho cliq

      Is there any way to answer from zoho cliq  the chat of salesiq initiated by customers?

    • Les dernières avancées en saisie de données et collaboration

      Après une année dédiée à la recherche et au développement, notre équipe est prête à dévoiler des améliorations majeures pour Zoho Sheet. Ces nouveautés seront lancées par étapes afin d’en assurer une prise en main optimale. Nous commençons avec des fonctionnalités

    • 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

    • Rich Text For Notes in Zoho CRM

      Hello everyone, As you know, notes are essential for recording information and ensuring smooth communication across your records. With our latest update, you can now use Rich Text formatting to organize and structure your notes more efficiently. By using

    • display call description in the notes section of a contact or add notes field to completed call screen

      When completing a call, we type in the result of the call in the description. However, that does not show up under the notes history on the contact. We want to be able to see all the calls that have taken place for a contact wihtout having to go into each completed call. The other option is to add the notes field to the completed call screen.

    • Implement Meeting Polls in Zoho Bookings

      Dear Zoho Bookings Support Team, We'd like to propose a feature enhancement related to appointment scheduling within Zoho Bookings. Current Functionality: Zoho Bookings excels at streamlining individual appointment scheduling. Users can set availability

    • Zoho Bookings and Survey Integration through Flow

      I am trying to set up flows where once an appointment is marked as completed in Zoho Bookings, the applicable survey form would be sent to the customer. Problem is, I cannot customise flows wherein if Consultation A is completed, Survey Form A would be

    • Service Account Admin for API Calls and System Actions

      Hello, I would like to request the addition of a Service Account Admin option in Zoho product. This feature would allow API calls and system actions to be performed on behalf of the system, rather than an active user. Current Issue: At present, API calls

    • How to apply customized Zoho Crm Home Page to all users?

      I have tried to study manuals and play with Zoho CRM but haven't found a way how to apply customized Zoho CRM Home Page as a (default) home page for other CRM users.. How that can be done, if possible? - kipi Moderation Update: Currently, each user has

    • Please can the open tasks be shown in each customer account at the top.

      Hi there This has happened before, where the open tasks are no longer visible at the top of the page for each customer in the CRM. They have gone missing previously and were reinstated when I asked so I think it's just after an update that this feature

    • How to Customize Task Creation to Send a Custom Alert Using JavaScript in Zoho CRM?

      Hello Zoho CRM Community, I’m looking to customize Zoho CRM to send a custom alert whenever a task is created. I understand that Zoho CRM supports client scripts using JavaScript, and I would like to leverage this feature to implement the alert functionality.

    • Send Whatsapp with API including custom placeholders

      Is is possible to initiate a session on whatsapp IM channel with a template that includes params (placeholders) that are passed on the API call? This is very usefull to send a Utility message for a transactional notification including an order number

    • Configurable Zoho Cliq Notifications for Zoho People Alerts

      Hello Zoho People Product Team, Greetings and hope you are doing well. We would like to request an enhancement to Zoho People notifications, enabling a native delivery via Zoho Cliq with admin-level control, similar to the notification settings available

    • Shift-Centric View for Assigning and Managing Shifts in Zoho People

      Hello Zoho People Product Team, Greetings and hope you are doing well. This feature request is related to Zoho People - please don't move it to zoho one! We would like to submit a feature request regarding the shift assignment and management view in Zoho

    • Add Israel & Jewish Holidays to Zoho People Holidays Gallery

      Greetings, We hope you are doing well. We are writing to request an enhancement to the Holidays Gallery in Zoho People. Currently, there are several holidays available, but none for Israel and none for Jewish holidays (which are not necessarily the same

    • Keep Zoho People Feature Requests in the Zoho People Forum

      Hello Zoho People Product Team, Greetings. We would like to submit a feature request regarding the handling of feature requests themselves, specifically for Zoho People. Issue: Feature Requests Being Moved to Zoho One Zoho People feature requests are

    • ZO25: The refreshed, more unified, and intelligent OS for business

      Hello all, Greetings from Zoho One! 2025 has been a remarkable year, packed with new features that will take your Zoho One experience to the next level! From sleek, customizable dashboards to an all-new action panel for instant task management, we’ve

    • CRM gets location smart with the all new Map View: visualize records, locate records within any radius, and more

      Hello all, We've introduced a new way to work with location data in Zoho CRM: the Map View. Instead of scrolling through endless lists, your records now appear as pins on a map. Built on top of the all-new address field and powered by Mappls (MapMyIndia),

    • Introducing Multi-Asset Support in Work Orders, Estimates, and Service Appointments

      We’re excited to announce a highly requested enhancement in Zoho FSM — you can now associate multiple assets with Work Orders, Estimates, and Service Appointments. This update brings more clarity, flexibility, and control to your field service operations,

    • [Product Update] Locations module migration in Zoho Books integration with Zoho Analytics

      Dear Customers, As Zoho Books are starting to support an advance version of the Branches/Warehouses module called the Locations module, users who choose to migrate to the Locations module in Zoho Books will also be migrated in Zoho Analytics-Zoho Books

    • Introducing Schedules for smarter availability management

      Greetings from the Zoho Bookings team! We’re excited to introduce Schedules, a powerful enhancement to manage availability across your workspace. Schedules are reusable working-hour templates that help you define and maintain consistent availability across

    • Why Zoho Contracts Prefers Structured Approvals Over Ad-hoc Approvals

      Approvals are one of the most important stages in a contract’s lifecycle. They determine whether a contract moves forward, gets revised, or needs further discussion. The approval process also defines accountability within the organization. Zoho Contracts

    • Whatsapp Connection Status still "Pending" after migration

      Hello, I migrated my WhatsApp API to Zoho from another provider a day ago. So far the connection status is still “Pending”. There is a problem? How long does it usually take?

    • 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

    • Search Bar positioning

      Why is the Search bar on the far right when everything is oriented towards the left?

    • How to use Rollup Summary in a Formula Field?

      I created a Rollup Summary (Decimal) field in my module, and it shows values correctly. When I try to reference it in a Formula Field (e.g. ${Deals.Partners_Requested} - ${Deals.Partners_Paid}), I get the error that the field can’t be found. Is it possible

    • Next Page