GSTR-3B Filing API

File the monthly GSTR-3B summary return via API. Auto-computes liability, offsets ITC, and submits to GSTN through the GSP channel.

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What is the GSTR-3B Filing API?

GSTR-3B is the self-declared summary return filed monthly. The WhiteBooks GSTR-3B Filing API accepts the summary table (outward, inward, ITC, late fees, interest) as JSON and submits to GSTN. It returns the ARN + acceptance status.

The API also offers ITC offset automation — pass your available ITC ledger balances and the API computes the optimal offset against IGST / CGST / SGST liability per Section 49 of the CGST Act, then submits the final return.

Quick spec

Code examples

curl Node.jsPythonJava 
curl -X POST 'https://apisandbox.whitebooks.in/gst/api/v1/gstr3b/file' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{ /* payload */ }'
Node.js 
const res = await fetch('https://apisandbox.whitebooks.in/gst/api/v1/gstr3b/file', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer ' + accessToken,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify(payload),
});
const data = await res.json();
Python 
import requests

resp = requests.post(
    'https://apisandbox.whitebooks.in/gst/api/v1/gstr3b/file',
    headers={'Authorization': f'Bearer {access_token}'},
    json=payload,
)
data = resp.json()
Java 
HttpRequest req = HttpRequest.newBuilder()
    .uri(URI.create("https://apisandbox.whitebooks.in/gst/api/v1/gstr3b/file"))
    .header("Authorization", "Bearer " + accessToken)
    .header("Content-Type", "application/json")
    .post(BodyPublishers.ofString(payload))
    .build();
HttpResponse<String> resp = HttpClient.newHttpClient()
    .send(req, BodyHandlers.ofString());

Integrate in 3 steps

  1. Sign up at accounts.whitebooks.in — sandbox credentials issued instantly, no sales gate.
  2. Make your first call against the sandbox base URL using the code example above. Validate against your local model.
  3. Move to production once your tests pass — switch host to https://api.whitebooks.in/gst. Same payload, same response shape.

Frequently asked questions

Does the API auto-calculate tax liability?

Yes — pass the line items and the API computes IGST / CGST / SGST / cess automatically.

Can it auto-offset ITC?

Yes. Pass your ITC ledger balances; the API applies Section 49 offset rules and returns the cash-leg payable.

What if upstream GSTN returns a transient error?

WhiteBooks auto-retries with exponential backoff (250ms / 500ms / 1s / 2s / 4s). Persistent errors surface as HTTP 5xx with retry-after.

Is late-fee + interest computation supported?

Yes. Pass filing date and the API computes late fees + interest per current CBIC rates.

Explore the full GST API

This is one endpoint inside the WhiteBooks GST API suite. See the full documentation — every endpoint, every parameter, every error code.

Open the GST API page →

Related GST API endpoints

GSTR-1 Filing API → GSTR-2B Fetch API → GSTR-9 Annual Return API → GSTR-2B Reconciliation API →
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