#tax

Validate and decode Indian GSTINs (the 15-character Goods & Services Tax Identification Number) instantly and entirely offline. The validate endpoint checks the structure and recomputes the official GSTIN check digit — the base-36 weighted algorithm the GSTN itself uses — and confirms the embedded state code is real, returning a clear valid/invalid verdict with the specific reasons a number fails. The decode endpoint breaks a GSTIN into its parts: the GST state/UT code and its name, the embedded 10-character PAN, the PAN holder type (company, individual/proprietor, firm/LLP, HUF, trust, government and more, read from the PAN's 4th letter), the entity registration number, the default 'Z' slot and the check digit. A states endpoint returns the full GST state-code reference for building dropdowns and lookups. Everything is pure computation — no network call, no key, no cache — so it is fast and private, ideal for checkout and onboarding forms, invoicing and e-invoice/e-way-bill pipelines, vendor master data cleansing and bulk validation. A structural GSTIN validator and decoder — distinct from EU VAT-number validation (vat), IBAN bank-account validation (iban) and card-number checks (creditcard). Note: this verifies the number's structure and check digit, not whether it is actively registered in the GSTN portal. No upstream key, no cache.

api.oanor.com/gst-api

VAT, GST and sales-tax rates for 128 countries — plus US state and Canadian province sub-rates — with a built-in tax calculator. Get the standard rate for any country (e.g. DE → 19%), compute the tax and gross total on a net amount (e.g. €100 in Germany → €19 tax, €119 total), apply a US state or Canadian province rate, or list every country. Ideal for e-commerce checkouts, invoicing, SaaS billing and pricing tools. (Standard rates, not tax advice.)

api.oanor.com/vat-api