GSTIN format explained: what the 15 characters mean
A GSTIN is 15 characters: state code, PAN, entity code and a check character. See what each part means, the checksum as working code, and what it cannot prove.
Last reviewed 4 October 2026
How to read a vendor's GST return history
What GSTR-1 and GSTR-3B show, how to read a real filing history month by month, and what a gap can and cannot tell you about a supplier. With a live example.
Last reviewed 4 October 2026
Monthly vs quarterly GST filers (QRMP): why a quiet vendor may not be late
A quarterly GST filer legitimately shows no return for two months out of three. How the QRMP scheme works, its due dates, and how to check a vendor's choice.
Last reviewed 4 October 2026
Can you search a GSTIN by company name? What works and what does not
The GST portal searches by GSTIN, PAN, temporary ID and composition status, not by name. What that means, and the routes that do work from a company name.
Last reviewed 4 October 2026
What to check before you pay a GST supplier, and what a cancelled registration means for your ITC
Five checks to run on a supplier's GSTIN before you pay, and how a cancelled registration or unfiled returns bear on your input tax credit under Section 16.
Last reviewed 4 October 2026
Live vs cached GST data: why a GSTIN check should hit the source
A cached GSTIN record can say Active after a registration was cancelled. Why we never cache lookups, the one place we store snapshots, and how to test any API.
Last reviewed 4 October 2026
Check a GSTIN from Claude: setting up the gstinapi MCP server
Set up the gstinapi MCP server in Claude Desktop or Claude Code to verify GSTINs and read GST filing history in conversation. Seven tools and the config.
Last reviewed 4 October 2026
One call instead of three: the GSTIN Complete Profile endpoint
GET /v1/gstin/{gstin}/complete returns registration, constitution, filing frequency and last filed GSTR-1 and GSTR-3B in one 2-credit call. A live example.
Last reviewed 4 October 2026
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