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:


      Zoho Campaigns Resources


        • Desk Community Learning Series


        • Digest


        • Functions


        • Meetups


        • Kbase


        • Resources


        • Glossary


        • Desk Marketplace


        • MVP Corner


        • Word of the Day


        • Ask the Experts


          • 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

          Zoho CRM Plus Resources

            Zoho Books Resources


              Zoho Subscriptions Resources

                Zoho Projects Resources


                  Zoho Sprints Resources


                    Zoho Orchestly Resources


                      Zoho Creator Resources


                        Zoho WorkDrive Resources



                          Zoho CRM Resources

                          • CRM Community Learning Series

                            CRM Community Learning Series


                          • Tips

                            Tips

                          • Functions

                            Functions

                          • Meetups

                            Meetups

                          • Kbase

                            Kbase

                          • Resources

                            Resources

                          • Digest

                            Digest

                          • CRM Marketplace

                            CRM Marketplace

                          • MVP Corner

                            MVP Corner




                            Zoho Writer Writer

                            Get Started. Write Away!

                            Writer is a powerful online word processor, designed for collaborative work.

                              Zoho CRM コンテンツ




                                ご検討中の方

                                  • Recent Topics

                                  • Adding Images to a Quote in Zoho CRM

                                    We are currently preparing to use Quotes in Zoho CRM and we are building out our Quote templates.  We came across an issue of not being to add Images of the products to the Quote - specifically in the body of the Quote templates.   This is a problem,

                                  • Applications built with Zoho Creator

                                    Hi, I’m really interested in seeing how others have built their application using Zoho Creator, especially those designed for external users (clients, vendors, or the public). If you’ve developed something along those lines and don’t mind sharing, I’d

                                  • Is it posssible to add Asap Widget on Wordpress?

                                    I have tried to add the ASAP widget so users could iniciate chats and see the KB information but nothings seems to work. I have tried to add the script using a php snippet that adds the to the footers and also tried one for the header in the functio

                                  • Require ticket resolution

                                    Hi Zoho team, Is there a way to require resolution even if an agent did not use a blueprint? for example, our blueprint has a "resolve" transition but what if agent revoked blueprint and manually set the status of ticket to closed? Is there a way where

                                  • Tables from ZohoSheets remove images when updated from source

                                    I have a few tables from a ZohoSheet in a ZohoWriter document that will remove the images in the cells when I refresh from the source. The source still has the images in the table when I go to refresh. After updating from the source, as you can see the

                                  • API Pagination Error: 'from' Parameter Limit

                                    Hello, I am encountering an error while paging through the Zoho Desk API results: Status code: 422 - {"errorCode":"UNPROCESSABLE_ENTITY","message":"The value passed for field 'from' exceeds the range of '0-4999'."} Is 5000 the maximum number of records

                                  • How to go to the next open ticket in the queue when agents closes ticket

                                    Zoho Desk When agent closes a ticket - eg when they choose 'Send and Close" - where is the setting that automatically redirects them to the next open ticket in the queue?

                                  • Custom templates for calendar report

                                    What about being able to design custom templates for the calendar report, as well as for other types of reports? I think more users are waiting for this.

                                  • Disable payment thank-you emails

                                    Hello, can someone please tell me how to disable sending of the "Payment Thank-You" emails? 

                                  • Maximum tags possible in Contacts Records

                                    I read in some documentation that Zoho allows a total of 200 tags across all records. Is this correct? So is it not possible to have one tag per record for 500 records?

                                  • Any way to "Pay with Check" or "Refund with Check" for Credit Notes?

                                    When we have a Bill in Zoho Books, we can select the "Pay with Check" option which then allows us to print/cut the check directly out of Zoho Books. When we created a Credit Note and want to refund the customer, is there any way to Refund with Check,

                                  • CRM Mobile reports

                                    When our engineers finish a job they like to email the customer a job report. This is best done todate as an email template but we can find no way to include an image field from that module. Is there any other options?

                                  • ¿How to integrate Zoho Inventory to Zoho SalesIQ?

                                    Is it possible to integrate Zoho Inventory with SalesIQ? I want to integrate it because I have a bot in Zoobot that uses a ChatGPT assistant. I need it to check the inventory of our items so it can determine whether or not our items are available.

                                  • When Zoho Tables Beta will be open to EU data center

                                    Hello all, We in EU are looking at you all using and testing and are getting jealous :) When we will be able to get into the beta also? We don't mind testing and playing with beta software. Thank you!

                                  • Start Form on a different page (i.e., hide form pages)?

                                    I have a Zoho form that uses the `Field Alias - Prefill URL` feature. My goal is to have a pre-filled field that directs the user to a specific starting page in the form. For example: The URL will have a field alias that will auto-populate a field with

                                  • How can we disable "My Requests"?

                                    We are not using this functionality in our system at all and our users get confused.

                                  • PayPal payment received recording problem

                                    Hi, A little while back one of our customers used the PayPal payment option to pay an invoice For some reason though the payment is showing up twice within the Payments section of the invoice! Instead of setting the invoice value to ZERO, it now shows a negative value Anyone else face this problem? I've checked PayPal and there is only 1 payment in reality... A bug? Actonia ps: for anyone from Zoho Customer Service or tech team,  its Invoice 785 in our account

                                  • server response: 451.4.7.1

                                    Good day.  Some email clients of our domain receive an error about sending and receiving letters. while for the rest everything works fine. access to the mail made by pop protocol. Bless the mistakes: "server response: 451.4.7.1 System error". 

                                  • string(87) "{"code":"INVALID_TOKEN","details":{},"message":"invalid oauth token","status":"error"} " grtting this error

                                    Using access token i am trying to add sales orders through api but it is throwing errors like the above i have mentioned. Please help me for that

                                  • How to mute chat notification sound by default in Zoho SalesIQ?

                                    We’ve recently embedded the Zoho SalesIQ chatbot on our website, and we’ve noticed that notification sounds sometimes play even when the visitor hasn’t interacted with the chat widget yet. We’re trying to understand two things: Why do these sounds occur

                                  • Kanban View for Projects.

                                    At our organization, we describe active projects with various statuses like "In Proofing" or "Printing" or "Mailing". In the Projects view, one can set these project statuses by selecting from the appropriate drop-down. While this works, it's difficult to view and comprehend the progress of all of your projects relative to each other in a table. Creating a Kanban view for projects where I can move them from one status to another allows me to see where each project is in the order of our workflow.

                                  • How to Hide Article Links in SalesIQ Answer Bot Responses

                                    I have published an article in SalesIQ, and the Answer Bot is fetching the data and responding correctly. However, it is also displaying the article link, which I don’t want. How can I remove the link so that only the message is shown?

                                  • Currency limitation when integrating Zoho CRM & Zoho Books

                                    Brief Video of Problem: https://www.loom.com/share/d61d1d07d0904e149d80c1901a22418e. Background ·       Our business is based in Australia and we have to have Zoho Books in AUD to comply with tax and reporting regulations in Australia. ·       We sell

                                  • Add RECURRING option when adding email to calendar events

                                    When you add an email to a calendar event, there is no option to make that new calendar event into a recurring event.  It is counterproductive to make an event from your email to then have to go to your calendar, find the event, and make it recurring. 

                                  • LINE Auto Message Connect to Zoho

                                    When I integrated LINE into the CRM, I was prompted to disable “Chat,” “Auto Response,” and “Greeting Messages,” and to enable the webhook. However, since I have already set up some auto-reply features in LINE, including Rich Messages and greeting automation,

                                  • Option to block bookings from specific email address or ip adresss in zoho booking

                                    Sometime few of our client keep booking irrelevant booking service just to resolve their queries and they keep booking it again and again whenever they have queries. Currently its disturbing our current communication process and hierarchy which we have

                                  • Threaded conversations for emails sent via automation

                                    Hi Guys, I hope you are doing well. Don't you guys think we should have an option in a workflow to notify users either as a new email or the previous email thread. For example, if you have one deal in the process and there are 10 different stages during

                                  • Create folder is fetch fails

                                    coming from zapier... zapier has a google drive task that searches for a specific folder in google drive, and if it fails to find the folder it will create a folder based on the search criteria, and contine along the singluar path of the flow. Trying

                                  • Meetups de Usuarios de Zoho - Noviembre 2025

                                    ¡Hola, Comunidad! Durante el mes de noviembre celebraremos los Meetups de usuarios de Zoho, encuentros presenciales pensados para quienes queráis mejorar vuestras estrategias de lead nurturing y aprender a sacar el máximo partido a herramientas como Zoho

                                  • Introducing 8 New Connectors in Zoho DataPrep!

                                    We’ve just made data management even easier - Zoho DataPrep now supports 8 new external connectors to help you build more robust, scalable ETL pipelines. Why it matters: ✅ Broader data access ✅ More automation, less manual work ✅ Smarter pipelines, better

                                  • First day of trying FSM in the field.

                                    What we found. 1. with out a network connection we were unable to start a service call? 2. if you go to an appointment and then want to add an asset it does not seem possible. 3. disappointed not to be able to actually take a payment from within the app

                                  • How to Automate Email Sequence

                                    I'm having trouble trying to set up a workflow to automate an email sequence. Once a group of emails in a Task has been tagged by a certain tag, I want an instant email template to be sent. After 7 days with no response, another email template would be

                                  • Zoho Sprints Android v2.0.4 app update: Item reminders, archive Epics, Kanban projects, Epic progress

                                    Hello everyone! In the latest version(v2.0.4) of the Zoho Sprints Android app update, we have introduced various new features. Let's take a look at what's new! Item Reminder Stay organized and never miss an important date with the all-new Item Reminder

                                  • Credit Management: #3 Setting Credit Limit for Customers

                                    Think about that one familiar customer of yours who always buys on credit. They usually pay on time, maybe a little late here and there, but not alarming. So, you are fine saying, "Sure, pay later." Then, one day, they place a significantly bigger order

                                  • Update on the client portal URL for Guest users

                                    We’re updating the way Guest users access their Connect network. As part of this change, all client organization portals used by Guest users will now be accessible through a dedicated domain specific to each data center. The access URLs mentioned here

                                  • Unable to see Zoho contacts in Zoho app on ios

                                    Hi Support Team, I am a new user, I have created my account and installed zohomail app on iOS 16 which works. I was also able to import my Gmail contacts into Zoho Contacts, which I can see. The problem is that I can’t see these imported cobalts in Zohomail

                                  • Task Due Date greater than 10 years.

                                    We use recurring tasks in Projects where every week, month, year etc Some of our projects are greater than 10 years and we are unable to set a new due date because the difference between start date and due date is greater than 10 years. As an example

                                  • External User onboarding for zoho connect is not really intuitive.

                                    So the external user is sent an invite, which has a button that directs them to login to zoho to view the invite, but if they don't have a zoho account, they cannot access that invite, which seems kinda silly, as there is not real way on for them to create

                                  • Hosting external websites on Zoho?

                                    How can I host my external website on zoho? Do we have that option? I am currently with hostinger and am looking to switch to zoho. Kindly help. Thanks.

                                  • How to Add Time Formula Duration (hh:mm)

                                    Hi everyone — I’m trying to create a formula field in Zoho CRM that calculates the difference between a “Call Start Time” and “Call End Time” and displays the duration in HH:MM format (for example: 1:04 for one hour and four minutes). My current setup

                                  • Next Page