GST API client libraries

Two official, MIT-licensed, zero-dependency clients for the GSTIN API GST verification service — one for Node.js and TypeScript, one for Python. Both validate a GST number offline for free, and both call the live register when you need to know who is actually behind it.

Install

Pick your language. The two libraries have the same shape on purpose: the same two layers, the same error taxonomy, and the same command-line tool.

npm install @dlminds/gstin-api

npx @dlminds/gstin-api explain 27AAACR5055K1Z7

pip install gstin-toolkit

pipx run --spec gstin-toolkit gstin-api explain 27AAACR5055K1Z7

Two layers, and most projects need one

Every GST API SDK question eventually reduces to this distinction. Validation is arithmetic you can do on your own machine. Verification is a question only the government register can answer, and it is the only half that costs anything.

A cancelled GSTIN passes every offline check ever written, because checksums do not expire. That single fact is why the online layer exists — and why validation and verification are not synonyms.

The same program, twice

Side by side, so a team running Python on the back end and Node on the edge can read one and understand both.

import { isValidGstin, parseGstin, GstinApiClient } from '@dlminds/gstin-api';

isValidGstin('27AAACR5055K1Z7');       // true — format + check digit, offline
parseGstin('27AAACR5055K1Z7').state;   // 'Maharashtra'

// Reads GSTINAPI_API_KEY from the environment. One credit per lookup.
const taxpayer = await new GstinApiClient().lookup('27AAACR5055K1Z7');

taxpayer?.legalName;                   // 'RELIANCE INDUSTRIES LIMITED'
taxpayer?.isActive;                    // true — the thing a checksum cannot tell you
// null instead of an object means no registration exists. That is not billed.

from gstin_api import is_valid_gstin, parse_gstin, GstinApiClient

is_valid_gstin("27AAACR5055K1Z7")     # True — format + check digit, offline
parse_gstin("27AAACR5055K1Z7").state  # 'Maharashtra'

# Reads GSTINAPI_API_KEY from the environment. One credit per lookup.
taxpayer = GstinApiClient().lookup("27AAACR5055K1Z7")

taxpayer.legal_name                   # 'RELIANCE INDUSTRIES LIMITED'
taxpayer.status                       # 'Active' — what a checksum cannot tell you
# None instead of an object means no registration exists. That is not billed.

Both ship a command-line tool for the times a script is more than you want to write — pipe a CSV column through it and get a verdict per row. The full surface is in the API documentation, and the raw endpoints are described by the OpenAPI spec.