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

                                  • Filtering report embeded in page

                                    Right now we are using a page variable to filter a report on a page. However, it being a page variable makes it reset if you go to another report/form, we want the filter to be kept the same. I tried using an application variable according to zoho you

                                  • Zia summarizes your IM bot chats in real time

                                    Hello everyone! Let's say you’re an agent taking over a chat where a customer was booking a flight through a bot on WhatsApp. They've already shared key details, like their destination, travel date, and number of passengers. You need to understand the

                                  • Megamenu

                                    Finally! Megamenu's are now available in Zoho-Sites, after waiting for it and requesting it for years! BUT ... why am I asked to upgrade in order to use a megamenu? First: Zoho promised to always provide premium versions and options for all included Zoho-applications

                                  • Cancel and refund

                                    Hi, Yesterday I paid for the Zoho email subscription. Within a few minutes, I realized that the subscription counts one email ID as one user. To make another email ID for the same domain name, I'd have to pay for another user. I emailed right away to

                                  • Kaizen# 209 - Answering Your Questions | All About Client Script

                                    Hello everyone! Welcome back to another exciting Kaizen post! Thanks for all your feedback and questions. In this post, let's see the answers to your questions related to Client Script. We took the time to discuss with our development team, carefully

                                  • To Do: shareable task links without login

                                    Hi! I’m using Zoho Mail and ToDo in my daily work, and I’ve run into one limitation that’s a real blocker for me. Right now, to share tasks with managers or directors, they need to have a Zoho account and be added to a group. In practice, many of them

                                  • Ability to turn off "Would you like this amount to be reflected in the Payment field?" message

                                    Team, Is there any way to turn off the message" Would you like this amount to be reflected in the Payment field?" when I make a payment? This is so annoying. This happens EVERY TIME I put an amount in the Payment Made field.

                                  • Unlock agreement intelligence with Zoho Sign's latest AI updates

                                    Hello! If you've been struggling with long, complex agreements and spending way too much time on them, here's exactly what you'll want to hear: Zoho Sign now integrates with OpenAI's ChatGPT to make agreement management smarter and simpler. Acting like

                                  • Currency abbreviations

                                    Hello, Im stuck, and need help. I need the currency fields for example, opportunity value, or total revenue, to be abbreviated, lets say for 1,000 - 1K, 1,000,000 - 1M, and so on, how should I do this?

                                  • Embed Sign Document

                                    Has anyone tried embedding a document in a webpage? I'm building a webpage (using PowerPage) and I'm trying to embed it using an iframe then I got this error: Refused to display 'https://sign.zoho.com/' in a frame because it set 'X-Frame-Options' to

                                  • We’re transitioning from Zoho ShowTime to TrainerCentral

                                    Hello everyone, Zoho ShowTime was originally built as a training platform to serve training agencies, HR teams, and individual trainers. As the platform grew, we realized that more creators and businesses could benefit from its capabilities. That’s why

                                  • Emails Are Not Being Delivered to My Inbox

                                    Hello Zoho Support Team, I am experiencing an issue with my Zoho Mail account. The most important problem is that emails are not being delivered to my inbox. Details: My Zoho Mail address: info@coreforcelife.com What happens: I am not receiving any incoming

                                  • Radar In Focus: Track customer support metrics using Radar's static reports

                                    Hello everyone, Welcome back to the Radar In Focus series, where we explore how Radar features can add value to your business. In this episode, we're looking at Radar static reports. The help desk is filled with vast amounts of data that can be analyzed

                                  • Mail ToDo & Tasks Webhooks

                                    Our company uses Zoho ToDo inside Mail to manage our tasks. When I create a task and assign it to a team member it does not notify them unless I add a reminder via mail. I'm trying to create a webhook for when a task is created to send a cliq message

                                  • Improved UI for a Seamless User Experience - Calls, Tasks, and Meetings

                                    Hello all, We are making UI unification across CRM so that the UI experience is seamless across the product. As part of that effort, we have made changes to the details page of activity-based module records—Meetings, Calls, and Tasks. Let's look at these

                                  • Where can I find rejected inbound mails and their reason for rejection

                                    Hi, I was recently made aware by a mailing list which I am subscribed to (ffmpeg-devel@ffmpeg.org) that my Zoho mail Mail account is rejecting some emails. If I look under Admin Panel > Security & Compliance > Quarantine > Incoming, the list there is

                                  • Refund

                                    Hi There, Please refund me asap possible, because of no support given. Thank you

                                  • تغيير عمله الدفع"Change payment currency"

                                    ما هى طريقه تغيير عمله الدفع "ما هي طريقة تغيير عملة الدفع؟"

                                  • Attention API Users: Upcoming Support for Renaming System Fields

                                    Hello all! We are excited to announce an upcoming enhancement in Zoho CRM: support for renaming system-defined fields! Current Behavior Currently, system-defined fields returned by the GET - Fields Metadata API have display_label and field_label properties

                                  • Zia's ability to generate and improve content extended to Desk mobile app (iOS and Android)

                                    In support, agents will have to understand customers' pain points completely to provide empathetic personalized solutions and a positive experience. However, at times, agents might find it challenging to comprehend the customer issues and connect with

                                  • BANK FEED - MAYBANK , provider from YODLEE IS NOT WORKING

                                    As per topic, the provider YODLEE is not working for the BANK FEED. It have been reported since 2023 Q3, and second report on 2023 Q4. now almost end of 2024 Q1, and coming to 2024 Q2. Malaysia Bank Maybank is NOT working. can anyone check on this issue?

                                  • Zoho Sign product updates - Q3 2025

                                    Hello everyone! Q3 was all about AI. Here's the list of features and enhancements that have gone live, along with a list of what we have in pipeline for the last quarter: AI-powered agreement management Sending documents and authenticating recipients

                                  • Zoho sites header

                                    Good day, Im stuck with this situation. I choose a template for my website creation. I have tweaked every instance of the visual editor, regarding the header, I have created created customize fonts presets... I have followed every single step. and my

                                  • 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

                                  • DNS set up

                                    I want to create an email with my company domain. When I tried to add new record with cloudflare it didn't work. The DNS record can't be manually added. I followed the instruction but still can't add it. Could you help?

                                  • Pocket from Mozilla is closing shop. Don’t lose your favorites . Move them to Zoho Mail Bookmarks now! 📥🔖

                                    The end of Pocket shouldn't mean the end of your important links and content. Easily import them into Zoho Mail's Bookmarks and continue right where you left off. You can bring over your entire Saves, Collections, and tags just the way they are. Bookmarks

                                  • General suggestions

                                    Hello, I've picked this forum as it is at the top of the list! :) First suggestion: A general forum for issues and comments that are not specific to a particular Zoho application. Second suggestion: Put a link on the home page to "Zoho Identity Access Manager" The first suggestion came about because I didn't know where to post the second! ;) Regards Mark

                                  • Can't upload attachments.

                                    I can't upload attachment in Zoho Mail.

                                  • Need Guidance on SPF Flattening for Zoho Mail Configuration

                                    Hi everyone, I'm hoping to get some advice on optimizing my SPF record for a Zoho Mail setup. I use Zoho Mail along with several other Zoho services, and as a result, my current SPF record has grown to include multiple include mechanisms. My Cloudflare

                                  • How use

                                    Good morning sir I tried Zoho Mail

                                  • Zoho Mail Desktop App Not Loading + Can’t Manage Multiple Accounts

                                    Hi everyone, I’ve been having ongoing issues with the Zoho Mail desktop app for the past few weeks. The app starts to load but gives up midway and never actually opens — there’s no error message, it just stops loading. The main reason I use the desktop

                                  • Error when sending emails from Zoho

                                    Hello, When trying to send an email from Zoho CRM I keep getting the below error: javax.mail.AuthenticationFailedException: 535 5.7.139 Authentication unsuccessful, the user credentials were incorrect. Any support on this will be much appreciated. Thanks,

                                  • Not all emails from outlook365 migrated to my new zoho account

                                    I recently setup a new email address hosted by zoho. I migrated all my folders and email from my Outlook365 account to my new zoho account, but not all my emails migrated. Looks like only the past 12 months, or so, made the move. How do I get the rest

                                  • Max numbr of IMAP Accounts in Zoho Mail?

                                    In Zoho mail, you can manage the inboxes of other accounts using IMAP (and POP, actually) https://www.zoho.com/mail/help/external-imap-accounts.html Is there a max to the number of inboxes we can add?

                                  • Formula Fields Trouble

                                    Hi,  I can't get even a simple formula field to work and must be doing something dumb. This formula: If(Len(Trim(${Quotes.Subject}))=0,1,2) Gives the error: You used the wrong type of data in an argument. Check what you entered between the parentheses of your functions to make sure you put the right kind of data in the right place. This formula: Len(Trim(${Quotes.Subject}))=0 Gives the error: Syntax Error. Check the examples for any functions you're using to see if you formatted them correctly. Make

                                  • OPTED FOR STORAGE BY DESCRIPTIVE MISGUIDANCE

                                    We've opened a domain with three mail ids and payment has also been processed now the bill raised is for single use ID with additional storage capacity. Kindly request you to modify the purchase.

                                  • How can I add a new organization on Zoho Campaign

                                    I want to create a new organization with my Zoho Campaign

                                  • www.abc.com is working but abc.com is not

                                    I have my domain in godaddy. I have created a website using zoho sites and now I want to publish it and I tried doing it. Mapped the domain www.abc.com, abc.com. In godaddy changed the CNAME values. A, @ was parked and updated with zoho's IP address.

                                  • Split my account

                                    Hello, I recently bought an email service for a friend. But, looks like I used my personal account to buy the plan. Please split the account so that the email service stays in a different account than my personal account.

                                  • Have Mail Lite, wish to add/purchase 2nd domain and use email

                                    Hello, I have recently created two new businesses. I have successfully used Zoho to create a domain for one business and have set up two email addresses / users on that domain. I am trying to figure out how to create a second domain, just like I did the

                                  • Next Page