# Fetch GSTR-1A Return Details for GST Checks API | FastKYC

> Retrieve GSTR-1A B2B invoice details for a GSTIN and return period, giving your GST reconciliation workflow the amendments a supplier has filed.

Source: https://www.fastkyc.com/apis/get-1a-data/

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[Identity APIs](/apis/identity/)

# Get 1A data API

Retrieve GSTR-1A B2B invoice details for a GSTIN and return period, giving your GST reconciliation workflow the amendments a supplier has filed.

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Category

[Identity APIs](/apis/identity/)

Built for

-   [Lending & NBFC](/industries/lending/)
-   [Marketplaces & E-commerce](/industries/marketplaces/)

## What the Get 1A data API does

Get 1A data returns the B2B invoice details filed under GSTR-1A for a given GSTIN and return period.

GSTR-1A captures amendments to outward supplies. Pulling it into reconciliation catches corrections a supplier made after their original filing, which is exactly the sort of change that otherwise causes an unexplained mismatch.

## Where teams use the Get 1A data API

1.  Reconciling amended supplier invoices
    
2.  Tracking corrections to outward supply filings
    
3.  Investigating mismatches in GST reconciliation
    
4.  Automating input tax credit checks
    

## Frequently Asked Questions (FAQs)

What is GSTR-1A?

The return capturing amendments to outward supplies previously reported. It records what changed after the original filing.

Why does it matter for reconciliation?

Amendments explain differences between what you recorded and what the supplier ultimately reported.

What do I need to query it?

The GSTIN and the return period.

## Related APIs

-   [Get 2A Data API Retrieve GSTR-2A B2B invoice details by GSTIN and return period to reconcile input tax credit against what your suppliers have actually filed.](/apis/get-2a-data/)
-   [Get 2B Data API Retrieve GSTR-2B ITC and reversal document details by GSTIN and return period, for accurate input tax credit computation and GST reconciliation.](/apis/get-2b-data/)
-   [Get 3B Data API Retrieve GSTR-3B summary return details for a GSTIN and return period, showing declared tax liability and credit for compliance and credit checks.](/apis/get-3b-data/)
-   [Generate E-Invoice API Generate a GST-compliant e-Invoice and receive the IRN, acknowledgement, signed invoice and QR code in one call, straight from your billing system.](/apis/generate-e-invoice/)

## Start verifying with the Get 1A data API

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