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 #198: Using Client Script for Custom Validation in Blueprint

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

    • Kaizen #226: Using ZRC in Client Script

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

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

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

    • Kaizen #217 - Actions APIs : Tasks

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

    • Kaizen #216 - Actions APIs : Email Notifications

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

    • Recent Topics

    • Notes - Reaction Buttons

      Using the native notes option within CRM is fine, it works and the RTF features are great, however, would it be possible - if there isnt already something in place, where we can add a reactions button, similar to teams/whatsapp to show that its been read

    • Lost the ability to sort by ticket owner

      Hi all, in the last week or so, we have lost the ability to sort tickets by Ticket Owner. Unlike the other columns which we can hover over and click on to sort, Ticket Owner is no longer clickable. Is it just us, or are other customers seeing this too?

    • Custom button for list page

      Why is my 'List Page - Bulk Action Menu' button in the Packages module not autopopulating the List argument with selected record IDs?

    • Rename system-defined labels in Zoho CRM

      Renaming system-defined labels is now available across all DCs. Hello everyone, Zoho CRM includes predefined system fields across modules to support essential CRM operations. Until now, the labels of these fields were fixed and could not be edited from

    • Exclude Email or Domain From New Ticket Notification

      Hi, we utilize the new ticket notification feature in Zoho Desk. However, it would be great if there was a way to exclude certain email addresses or domains from receiving the automatic notification. This would be particularly helpful for automated alerts

    • Anyone have a working connection with CRM and shipstation via Flow

      Just wondering if anyone has successfully integrated shipstation and Zoho CRM.  I know there’s code to do it but am hoping to find out all the pitfalls before I jump on!! Scenario: SalesOrder gets created in CRM with multiple line items. I want this pushed to shipstation. On shipping via shipstation I want to push the tracking # back to CRM.  Many thanks in advance

    • ShipStation and Zoho Inventory

      Hello, I am looking to sync zoho inventory with shipstation ZOHO INVENTORY           SHIP STATION Sales Order  ==>  create ORDERS INVOICE  <==    Shipments What exactly does BETA mean on the Shipstation connector?  This is required for me to sign-on in the next month. Thanks in advance for your efforts

    • Connect to Shipstation's API

      Shipstation is a very big service, with lots of users, tons of order data.....and poor un-customizable reporting. This is perfect for Zoho analytics.  The Shipstation API is modern and efficient.  Today I think many people pay Zapier to get Shipstation data into Reports/CRM/Books - why not have  a direct connection?  -can pull in shipments via webhook or polling.  -also nice to pull in order data along with shipment data

    • What’s the Correct Integration Flow Between Zoho Inventory, ShipStation, and Multi-Channel Sales Platforms?

      Hi Zoho Community, I’m currently implementing Zoho One to manage all of my business processes, and I’d appreciate some guidance on the correct integration flow for the tools I’m using. Here’s my current setup: Zoho Inventory is my central system for managing

    • Remove Zoho Header from Portals

      I have a portal page with custom domain. But when I print directly from a webpage, the Zoho CRM header shows. It kind of kills the branding aspect. Is there a way to get rid of this?

    • Setting defaults for "Find and Merge Duplicate for..."

      To remove some of the extreme tedium from Zoho's poorly implemented merge function, I would like to set defaults.  Currently I am defaulted to match "ANY" when I would never do that, so I always have to click "ALL". Then it makes me click on several totally irrelevant drop boxes to turn off phone, mobile and other useless match criteria. Is there a way I can set: Match to default as "ALL" Firstname to default to "IS" Lastname to default to "IS" every other match field default to "-NONE-" This will

    • Clone a Module??

      I am giong to repurpose the Vendors module but would like to have a separate but very similar module for another group of contacts called Buyers. I have already repurposed Contacts to Sellers. Is it possible to clone (make a duplicate) module of Vendors

    • Let's bring Manufacturing Resource Planning (MRP), Material Requirement Planning (MRP), and Production Planning/Management module / feature in Zohobooks

      Let's bring Manufacturing Resource Planning (MRP), Material Requirement Planning (MRP), and Production Planning/Management module / feature in Zohobooks

    • CLIENT PORTAL (If clients can place orders directly on the portal)

      Zoho client portal is excellent. Everything is there except one thing. Client should be able to place orders directly on the portal. This would enhance the portal and end users will be extremely happy. This suggestion infact came from one of our client.

    • Zoho → ShipStation Integration – Sales Order–Driven Fulfilment Workflow

      Hello All, I’m reaching out to explore the best way to integrate a shipping tool into our inventory which will speed our process up. We are looking to integrate ShipStation into our existing order-to-fulfilment workflow, as we’re keen to standardise on

    • Zoho Inventory Feature Roadmap Visible To All

      Hello, please consider making your feature roadmap visible to us users so that we know what to expect in future. This may appease current users who are seeking clarification on feature implementation dates, so that they can make an informed decision whether

    • アナリティクスで商談中のパイプライン(ステージ）の件数比較

      アナリティクスで商談中のパイプライン(ステージ）の件数を前週と前々週で比較したい。前々週の件数が更新することで変動してしまう。対象方法をご教授ください。

    • How do I remove a data source from Zoho Analytics?

      I am unable to find a delte option on a datasource that i put in the system as an error. On teh web it refers to a setup icon but I do not see that on my interface?

    • Identify and clean hard bounce lists in Automation 2.0

      Hello. 1. I want to know how I can identify hard bounces in the lists I created to clean them before sending an email, given that the bounce rate has increased and it is necessary to clean the lists. 2. How can I exclude hard bounces and invalid emails

    • Trigger workflows from SLA escalations in Zoho Desk?

      Hey everyone, I’m currently working with SLA escalation rules in Zoho Desk and ran into a limitation that I’m hoping someone here has solved more elegantly. As far as I can tell, SLA escalations only support fairly limited actions (like changing the ticket

    • Delete a department or category

      How do I delete a Department? Also, how do I delete a Category? This is pretty basic stuff here and it's impossible to find.

    • Zoho Webinar - Sharing System Audio (NOT AVAILABLE)

      Hi, We are having a serious problem with Zoho Webinar. In the webinars we run, we very often share the audio from a video we are streaming directly from YouTube or other applications. Until recently we were using Zoom, but as we use other Zoho applications

    • Cancellation Fees

      Hi, It really would be good if Billing could take subscription management further with cancellations & being able to apply or set a cancellation fee for a plan that is either fixed or prorated. It is not uncommon in subscriptions for cancellation fees

    • Custom Field for Subscription

      Hi, I can't find a way to add a custom field (to contain a license key generated from our software) against a subscription? Is the only place to add this information in the Invoice module (as custom field for invoice)? When a customer views his subscription

    • Zoho CRM Meetings Module Issues

      We have a use-case that is very common in today's world, but won't work in Zoho CRM. We have an SDR (Sales Development Rep) who makes many calls per day to Leads and Contacts, and schedules meetings for our primary Sales Reps. He does this by logging

    • How to get the campaingns key?

      Reading the documentations of the API, I see that is necessary have the campaign key, but I don't see how can I get it. For example to get the campaign details we need to do the request: https://campaigns.zoho.com/api/getcampaigndetails?authtoken=[API Authentication Token]&scope=CampaignsAPI&campaignkey=[campaignkey] I have the API Authentication Token but I don`t see how to generate the campaignkey

    • Unable to switch existing AWS RDS connection to DataBridge after moving RDS behind VPN

      Unable to switch existing AWS RDS connection to DataBridge after moving RDS behind VPN Hi everyone, I’m facing a problem with an existing Zoho Analytics setup and would like to know the best migration path. Originally, my Zoho Analytics connection to

    • [Bug] WebAuthn passkey registration blocked on rpIds with TLDs longer than 6 characters (.accountant, .technology, etc.) — isValidDomain regex too strict

      Hi, Filing on behalf of an enterprise customer where Zoho Vault is deployed across the company. The Chrome extension blocks WebAuthn passkey registration on legitimate sites whose Relying Party ID (rpId) has a TLD longer than 6 letters. This affects every

    • Native QuickBooks integration for Zoho CRM: Connecting sales and finance

      Greetings, I hope all of you are doing well. We're excited to announce Zoho CRM's integration with QuickBooks Web, which is designed to synchronize your CRM data with your QuickBooks accounting records and bridge the gap between sales and finance. This

    • Syncing zoho books into zoho crm

      I was wondering how I can use zoho books in crm as I have been using them separately and would like to sync the two. Is this possible and if so, how? Thanks

    • ZohoBooks_add_expense_attachment Fails

      I'm working MCP in Claude to automate bookkeeping. Claude cannot seem to attach and reciept to an expense. The 'add expense attachment' tool is added to the server and enabled in Claude. I asked Claude to give me the calls he performed and this is what

    • ZohoBooks_create_chart_of_account

      I'm setting up Claude to do my bookkeeping workflows using a Zoho MPC server I setup. He does not seem to be able to create a chart of account. The 'create chart of account' tool is added to the server and enabled in Claude. I asked Claude to give me

    • Zoho Books Product Road Map

      I am planning to look into Zoho Books to maintain my Company's Account Books. Is the roadmap of Zoho Books Development available online? What happens if you product dies, without an export feature to other popular Accounting softwares like Tally or Quickbook. Are we going to be left in lurch? Do you have a product road map? Regards, Vishal.

    • I want to delete the email but I can't.

      I want to delete emails but I can't, please help me. Thanks!

    • Error while creating new user

    • Zoho Mail is blacklisted on magicspam.com and spamauditor.org

      As of today, the same problem with the IP addresses 136.143.188.51 and 136.143.188.52 How long does it take them to clear their IP addresses? I've read on this forum that these IP addresses have been blacklisted for years. //////////////////////// This

    • Unable to send emails from the delegated mailbox

      currently it's not possible to send emails from our delegated mailbox (just in our own name, our own mail-accounts) The permissions granted include "Send as," and we are also unable to delete delegated employees or add new ones. We can only add employees

    • Change Password

      How can I reset OR Change the Passwords for the Whole Organization at Once as Administrator using Admin Console?

    • Zoho Books bill pay option not available with zoho one

      Why isn't Zoho Books bill pay add-on not available for Zoho one customers not even as a purchasable option. I think this is very inconvenient for companies wanting to use this feature all in one system

    • Support - what am I doing wrong?

      Hi Everyone - I'm a new user and looking particularly for a replacement mail service. I'm just a home user not a professional but I do look after half a dozen domains. Zoho looks lovely and I'd like to switch but just want to get answers to a few 'easy'

    • Next Page