GSTIN Verification API docs

Authentication

API key (header: X-API-Key)

Send your key on every request. Do not put keys in client-side code or public repos. Rotate keys from the dashboard if a secret is exposed.

X-API-Key: YOUR_API_KEY

Rate limits

Default catalog limit: From 10 req/min. Plan-specific limits apply after you subscribe. When throttled, expect 429 with a retryable response — back off and retry with jitter.

• Verify GSTIN: Plan-based
• Filing status: Plan-based

Errors

Errors return JSON with a machine-readable code and message. Common platform codes:

• 401 — missing or invalid API key
• 403 — key valid but not entitled for this API or plan
• 404 — resource or path not found
• 429 — rate limit exceeded; retry later
• 5xx — upstream or platform failure; retry with backoff

Endpoint-specific errors are listed under each endpoint below.

Versioning

Current documented version: v1. Prefer pinning the version path shown in examples. Breaking changes ship under a new version; check the changelog for platform updates.

Verify GSTIN

Validate a GSTIN and return registration details.

Parameters

Example code

curl -s "https://gstchk.apiseeker.com/v1/gstin/29ABCDE1234F1Z5" \
  -H "X-API-Key: YOUR_API_KEY"

Response example

{
  "gstin": "29ABCDE1234F1Z5",
  "valid": true,
  "legalName": "Example Private Limited",
  "tradeName": "Example",
  "status": "Active",
  "stateCode": "29"
}

Errors

• 400 — Invalid GSTIN format
• 401 — Missing or invalid API key
• 404 — GSTIN not found
• 429 — Rate limit exceeded

Filing status

Return recent GST return filing status for a GSTIN.

Parameters

Example code

curl -s "https://gstchk.apiseeker.com/v1/gstin/29ABCDE1234F1Z5/filings" \
  -H "X-API-Key: YOUR_API_KEY"

Response example

{
  "gstin": "29ABCDE1234F1Z5",
  "filings": [
    {
      "period": "2026-07",
      "type": "GSTR-3B",
      "status": "Filed"
    },
    {
      "period": "2026-06",
      "type": "GSTR-3B",
      "status": "Filed"
    }
  ]
}

Errors

• 400 — Invalid GSTIN format
• 401 — Missing or invalid API key
• 404 — GSTIN not found