> ## 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

> File GSTR-1 returns programmatically using Sandbox APIs—manage outward supplies, amendments, and compliance

# GSTR-1 API

GSTR-1 is a monthly or quarterly return for reporting outward supplies (sales). Use these APIs to save invoice data, retrieve summaries, and file returns directly to the GST portal.

This API enables automated GSTR-1 compliance covering all invoice types, amendments, credit/debit notes, exports, and HSN summaries.

<CardGroup cols={2}>
  <Card title="All GSTR-1 tables" icon="file-invoice">
    Save and retrieve B2B, B2C, exports, credit/debit notes, and nil supplies across all GSTR-1 tables.
  </Card>

  <Card title="Full filing workflow" icon="paper-plane">
    From saving invoices to generating EVC OTP and filing—handle the entire compliance workflow via API.
  </Card>
</CardGroup>

## How it works

<Steps>
  <Step title="Authenticate taxpayer">
    Generate OTP and verify to start a taxpayer session valid for 6 hours.
  </Step>

  <Step title="Save invoices">
    Upload invoice data (B2B, B2C, exports, CDN, etc.) to the GST portal.
  </Step>

  <Step title="Check return status">
    Verify saved data and check for errors or warnings.
  </Step>

  <Step title="Proceed to file">
    Generate the summary and mark the return ready for filing.
  </Step>

  <Step title="Get summary">
    Retrieve table-wise summary of GSTR-1 data for review.
  </Step>

  <Step title="Generate EVC OTP">
    Request OTP for Electronic Verification Code to authorize filing.
  </Step>

  <Step title="File return">
    Submit the GSTR-1 return to the GST portal.
  </Step>

  <Step title="Verify filing status">
    Confirm successful filing and retrieve acknowledgment.
  </Step>
</Steps>

## Recipes

Step-by-step guides for common GSTR-1 workflows:

<CardGroup cols={2}>
  <Card title="File GSTR-1" icon="paper-plane" href="/recipes/gst/gstr-1/file_gstr_1">
    Complete workflow to file GSTR-1 with outward supplies, amendments, and credit/debit notes.
  </Card>

  <Card title="File Nil GSTR-1" icon="file-circle-check" href="/recipes/gst/gstr-1/file_nil_gstr_1">
    File a nil return when there are no outward supplies for the period.
  </Card>
</CardGroup>

## API categories

<CardGroup cols={2}>
  <Card title="Document APIs" icon="file-lines" href="#document-apis">
    Retrieve invoice data for each GSTR-1 table (B2B, B2C, exports, CDN, HSN, etc.)
  </Card>

  <Card title="Filing APIs" icon="paper-plane" href="#filing-apis">
    Save data, proceed to file, generate summary, and submit returns
  </Card>

  <Card title="Return Status" icon="circle-check" href="/api-reference/gst/compliance/endpoints/taxpayer/common/gst_return_status">
    Check status after saving—view errors and validation info
  </Card>

  <Card title="Errors & Troubleshooting" icon="triangle-exclamation" href="/guides/developer-resources/errors">
    Understand error codes and resolve common issues
  </Card>
</CardGroup>

## Document APIs

Retrieve invoice and supply data for each GSTR-1 table:

| API                                                                                                   | GSTR-1 Table     | Description                                         |
| :---------------------------------------------------------------------------------------------------- | :--------------- | :-------------------------------------------------- |
| [GSTR-1 AT](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/at)                     | 11A              | Advances received (tax payable, invoice not issued) |
| [GSTR-1 ATA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/ata)                   | 11A (Amendments) | Amendment of advances reported earlier              |
| [GSTR-1 B2B](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2b)                   | 4A, 4B, 6B, 6C   | B2B invoices (incl. SEZ supplies & Deemed exports)  |
| [GSTR-1 B2BA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2ba)                 | 9A               | Amendment of B2B invoices                           |
| [GSTR-1 B2CL](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2cl)                 | 5A, 5B           | B2C Large invoices (inter-state above threshold)    |
| [GSTR-1 B2CLA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2cla)               | 9A               | Amendment of B2C Large invoices                     |
| [GSTR-1 B2CS](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2cs)                 | 7                | B2C Small (rate-wise consolidated)                  |
| [GSTR-1 B2CSA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/b2csa)               | 10               | Amendment of B2C Small (Table 7)                    |
| [GSTR-1 CDNR](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/cdnr)                 | 9B               | Credit/Debit Notes to registered persons            |
| [GSTR-1 CDNRA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/cdnra)               | 9C               | Amendment of CDNR (registered)                      |
| [GSTR-1 CDNUR](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/cdnur)               | 9B               | Credit/Debit Notes to unregistered persons          |
| [GSTR-1 CDNURA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/cdnura)             | 9C               | Amendment of CDNUR (unregistered)                   |
| [GSTR-1 Document Issued](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/doc_issue) | 13               | Documents issued (invoice series, DN/CN series)     |
| [GSTR-1 EXP](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/exp)                   | 6A               | Export invoices                                     |
| [GSTR-1 EXPA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/expa)                 | 9A (Exports)     | Amendment of export invoices                        |
| [GSTR-1 NIL Supplies](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/nil)          | 8A–8D            | Nil rated / exempt / non-GST outward supplies       |
| [GSTR-1 HSN Summary](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/get_hsn)       | 12               | HSN-wise summary of outward supplies                |
| [GSTR-1 TXP](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/txp)                   | 11B              | Advance tax adjusted against invoices               |
| [GSTR-1 TXPA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/txpa)                 | 11B (Amendments) | Amendments to advance adjustments                   |
| [GSTR-1 ECOM](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/ecom)                 | 14               | Supplies made through e-commerce operators          |
| [GSTR-1 ECOMA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/ecoma)               | 14A              | Amendments to Table 14                              |
| [GSTR-1 SUPECO](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/supeco)             | 15               | Supplies u/s 9(5) where ECO is liable to pay tax    |
| [GSTR-1 SUPECOA](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/documents/supecoa)           | 15A              | Amendments to Table 15                              |

## Filing APIs

Save invoice data and complete the filing workflow:

| API                                                                                         | Purpose                                           |
| :------------------------------------------------------------------------------------------ | :------------------------------------------------ |
| [Save GSTR-1](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/file/save)            | Upload invoice JSON to GST portal                 |
| [Reset GSTR-1](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/file/reset)          | Reset saved return data                           |
| [Proceed to File](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/file/new_proceed) | Generate summary and mark return ready for filing |
| [File GSTR-1](/api-reference/gst/compliance/endpoints/taxpayer/gstr-1/file/file)            | Submit the return to GST portal                   |

## Common APIs

Shared endpoints used across GSTR-1 workflow:

| API                                                                                                  | Purpose                                  |
| :--------------------------------------------------------------------------------------------------- | :--------------------------------------- |
| [Generate OTP](/api-reference/gst/compliance/endpoints/taxpayer/authentication/generate_otp)         | Start taxpayer authentication            |
| [Verify OTP](/api-reference/gst/compliance/endpoints/taxpayer/authentication/verify_otp)             | Complete authentication (6-hour session) |
| [Generate EVC OTP](/api-reference/gst/compliance/endpoints/taxpayer/authentication/generate_evc_otp) | Request OTP for filing authorization     |
| [Return Status](/api-reference/gst/compliance/endpoints/taxpayer/common/gst_return_status)           | Check status after saving return         |
| [Refresh Session](/api-reference/gst/compliance/endpoints/taxpayer/authentication/refresh_session)   | Extend taxpayer session                  |
| [Logout](/api-reference/gst/compliance/endpoints/taxpayer/authentication/logout)                     | End taxpayer session                     |

## Common use cases

Use GSTR-1 APIs when you need to:

* Automate monthly or quarterly GSTR-1 filing
* Bulk upload B2B and B2C invoices from your ERP or accounting system
* Amend previously filed invoice data
* File credit/debit notes for registered and unregistered recipients
* Generate HSN-wise summaries for compliance
* Build GST compliance into your SaaS platform

## Frequently Asked Questions

<AccordionGroup>
  <Accordion title="What is GSTR-1?">
    GSTR-1 is a monthly or quarterly return that registered taxpayers file to report details of outward supplies (sales). It includes B2B invoices, B2C sales, exports, credit/debit notes, and amendments.
  </Accordion>

  <Accordion title="What is the GSTR-1 filing workflow?">
    1. Authenticate using OTP to start a 6-hour session
    2. Save invoice data using the Save GSTR-1 API
    3. Check return status for errors
    4. Call Proceed to File to generate summary
    5. Generate EVC OTP for authorization
    6. File the return using File GSTR-1 API
    7. Verify filing status
  </Accordion>

  <Accordion title="What's the difference between B2B and B2CL?">
    **B2B**: Invoices to registered recipients (any value)\
    **B2CL (B2C Large)**: Inter-state invoices to unregistered recipients exceeding ₹2.5 lakhs
  </Accordion>

  <Accordion title="What is EVC OTP?">
    Electronic Verification Code OTP is required to authorize filing. After calling Proceed to File, generate EVC OTP and include it in the File GSTR-1 request.
  </Accordion>

  <Accordion title="How long is the taxpayer session valid?">
    The session started after OTP verification is valid for 6 hours. Use the Refresh Session API to extend if needed.
  </Accordion>

  <Accordion title="Can I reset a saved return?">
    Yes, use the Reset GSTR-1 API to clear saved data before filing. This is useful if you need to re-upload corrected invoice data.
  </Accordion>
</AccordionGroup>