> ## Documentation Index > Fetch the complete documentation index at: https://developer.sandbox.co.in/llms.txt > Use this file to discover all available pages before exploring further. # Overview > Verify GSTINs, monitor day-wise GSTIN changes, track GST return filing status, find GSTINs by PAN and state code, and validate unregistered applicants using Sandbox GST Public APIs. # GST Public APIs GST Public APIs give you access to GST registration and compliance data without requiring taxpayer credentials. Verify GSTINs, monitor day-wise GSTIN changes, track return filing status, find GSTINs by PAN and state code, and work with unregistered e-commerce applicants. ## What you can do > **GSTIN verification** > > Validate a GSTIN. Get business details: legal name, trade name, taxpayer type, registration status, and principal address. > **GSTIN change tracking** > > Retrieve GSTIN changes reported for a state on a selected date, with pagination support. > **Track GST return filing** > > Check whether a business has filed GST returns for a financial year, with optional filtering by return type. > **Find GSTINs by PAN** > > Discover GSTINs linked to a PAN in a specific state using state code. > **Unregistered applicant details** > > Retrieve GST registration details for an unregistered e-commerce applicant using an enrolment number. > **Validate applicant contacts** > > Validate the registered email address, mobile number, or both for an unregistered applicant. ## How it works **1. Authenticate with Sandbox** Generate a JWT access token using your API key and secret via the [Authenticate](https://developer.sandbox.co.in/api-reference/authenticate.md) API. **2. Verify a GSTIN** Call [Search GSTIN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_gstin.md) to verify GSTIN and fetch taxpayer details and registration status. **3. Monitor GSTIN changes** Call [Get day-wise changed GSTINs](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-day-wise-changed-gstins.md) with a state code and date to retrieve reported GSTIN changes. **4. Track return filing** Call [Track GST Returns](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/track_gstrs.md) with financial year and optional return type filter. **5. Find GSTIN by PAN** Call [Search GSTIN by PAN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_pan_state_code.md) with PAN and state code, then verify each GSTIN. **6. Work with unregistered applicants** Use [Get unregistered applicant details](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-unregistered-applicant-details.md) and [Validate unregistered applicants](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/unregistered-applicants-validation.md) with an enrolment number. ## API reference | API | Purpose | | :- | :- | | [Authenticate](https://developer.sandbox.co.in/api-reference/authenticate.md) | Generate a JWT access token using `x-api-key` and `x-api-secret` | | [Search GSTIN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_gstin.md) | Verify GSTIN and fetch taxpayer details and registration status | | [Get day-wise changed GSTINs](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-day-wise-changed-gstins.md) | Retrieve GSTIN changes for a state and date | | [Track GST Returns](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/track_gstrs.md) | Track return filing status by financial year with optional return type filter | | [Search GSTIN by PAN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_pan_state_code.md) | Find GSTINs using PAN and state code, then verify each GSTIN | | [Get unregistered applicant details](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-unregistered-applicant-details.md) | Retrieve unregistered applicant details using an enrolment number | | [Validate unregistered applicants](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/unregistered-applicants-validation.md) | Validate an applicant's registered email address, mobile number, or both | ## Common use cases Use GST Public APIs when you need to: * Verify GSTIN during vendor onboarding and validate status is Active and names match vendor details * Validate supplier GSTIN status before processing invoices for Active or Cancelled status * Track GST return filing history for supplier compliance monitoring across financial years * Find GSTINs when you only have PAN and state code, then verify the discovered GSTINs * Monitor GSTIN changes reported for a state to support compliance and onboarding workflows * Retrieve GST registration details for an unregistered e-commerce applicant * Validate an unregistered applicant's registered email address or mobile number before further communication * Build dashboards that monitor GSTIN status changes and filing behavior over time ## FAQ > **What are GST Public APIs?** > > GST Public APIs are Sandbox endpoints for public GST data. They let you verify GSTINs, monitor GSTIN changes, track return filing status, find GSTINs by PAN and state code, and work with unregistered applicants. No taxpayer credentials are required. > **Is Search GSTIN a GSTIN verification API?** > > Yes. Search GSTIN verifies whether a GSTIN belongs to a GST-registered business. It returns business details and registration status. Use [Search GSTIN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_gstin.md) for onboarding and compliance workflows. > **Do I need GST portal credentials for these APIs?** > > No. These are public endpoints. You only need Sandbox authentication via [Authenticate](https://developer.sandbox.co.in/api-reference/authenticate.md) to generate a JWT access token. Pass the token in the Authorization header (no Bearer prefix). > **How does authentication work for GST Public APIs?** > > Call Authenticate with your `x-api-key` and `x-api-secret` to generate a JWT access token. Then pass the token directly in the Authorization header when calling Search GSTIN. Sandbox tokens aren't Bearer tokens. > **What inputs are required for Track GST Returns?** > > Track GST Returns requires GSTIN in the request body and `financial_year` as a query parameter. Add the optional `gstr` query parameter to filter by return type. See [Errors](https://developer.sandbox.co.in/guides/developer-resources/errors.md) for troubleshooting. > **How do I find GSTIN when I only have PAN?** > > Use [Search GSTIN by PAN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_pan_state_code.md) with PAN in the request body and `state_code` as a query parameter. This returns GSTINs for the PAN in that state. Validate each GSTIN using [Search GSTIN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_gstin.md). > **How do I retrieve day-wise GSTIN changes?** > > Use [Get day-wise changed GSTINs](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-day-wise-changed-gstins.md) with a two-digit `state_code` and a `date` in `DD-MM-YYYY` format. Use the optional `page` field to retrieve subsequent pages. > **How do I work with unregistered applicants?** > > Use [Get unregistered applicant details](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/get-unregistered-applicant-details.md) with an `enrolment_number` to retrieve applicant details. Use [Validate unregistered applicants](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/unregistered-applicants-validation.md) with the enrolment number and at least one of `mobile` or `email` to validate registered contact details. > **What is x-accept-cache and when should I use it?** > > It's an optional header that returns cached responses when available. This speeds up repeated requests. Set it to true if your workflow can tolerate cached data. See endpoint docs for [Search GSTIN](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/search_gstin.md) and [Track GST Returns](https://developer.sandbox.co.in/api-reference/gst/compliance/endpoints/public/track_gstrs.md). This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.