FinAGG GSP Developer Portal

GST Suvidha Provider APIs
FinAGG GSP APIs
API docs by Redocly

FinAGG GSP APIs (1.0.0)

License: Proprietary

Overview

FinAGG GSP APIs provide secure, scalable, and compliant programmatic access to India’s GST ecosystem through an authorized GST Suvidha Provider (GSP).

GST Developer Portal https://developer.gst.gov.in

These APIs are intended for system-to-system integration and are not meant to be accessed via browsers, except for health and ping endpoints.

API Ecosystem

FinAGG GSP maintains multiple API servers for development, testing, and production usage.

Note: These are API servers and not meant to be browsable (except for Ping and GSTN Health endpoints).

Sandbox Environment

Production Environment

  • Base URL: https://gsp.finagg.in/basic/gstn/
  • Ping – Check if GSP is reachable
  • GSTN Health Check – Verify GSTN availability
  • SSL Certificate – Expiry: 28 AUG 2026

Supported Ecosystems

  • GST Ecosystem – Goods and Services Tax APIs via GSTN
  • NIC Ecosystem – eWay Bill APIs via NIC

Authentication

All APIs are protected using API Key authentication

(This you need to get from FinAGG GSP Team before you use these APIs, send a request to get the X-API-Key to gsp@finagg.in )

Required Header: x-api-key

Common APIs

Common GST services

Common GST Search API

Searches GSTN records for GSTIN validation and taxpayer status.

Use cases

  • GSTIN verification
  • Taxpayer status lookup
Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1
query Parameters
action
required
string
Example: action=OTPREQUEST

Responses

Common Returns Metadata

Fetches return availability and filing metadata from GSTN.

This API does not download files, but returns:

  • Available return periods
  • Filing status
Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

Taxpayer APIs

Taxpayer-specific services

Taxpayer Authentication (OTP Based)

Authenticates a GST taxpayer using OTP-based consent flow.

This step is mandatory before accessing:

  • Taxpayer returns
  • Return downloads
Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1
Request Body schema: application/json
required
action
string

Action Name

username
string

Your GST User Name

app_key
boolean

Unique App Key

Responses

Request samples

Content type
application/json
{
  • "action": "OTPREQUEST",
  • "username": "your_username",
  • "app_key": "app_key_you_generated_for_this_request_encrypted_by_provided_public_key"
}

Taxpayer Returns Summary

Retrieves GST return summary data for an authenticated taxpayer.

Includes:

  • Filing status
  • Period-wise return availability
Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

GSTR-1 Returns

Fetches GSTR-1 return data containing outward supply details.

Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

GSTR-2A Returns

Fetches GSTR-2A auto-drafted return reflecting inward supplies.

Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

GSTR-3B Returns

Fetches GSTR-3B summary return for tax liability and payment.

Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

CMP (Composition Scheme) Returns

Fetches Composition Scheme (CMP) returns for eligible taxpayers.

Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
gspVersion
required
string
Example: v1.1

Responses

File Download

Large GST file downloads

GST Return File Download

Downloads high-volume GST return files such as:

  • GSTR-1
  • GSTR-2A
  • GSTR-3B

This endpoint supports large payload streaming.

Authorizations:
ApiKeyAuth
path Parameters
finaggVersion
required
string
Example: fin-v1
proxy_path
required
string

GSTN file path returned by FILEDET API

Responses