GST API Integration Developer (Contract) — GSTR-3B Filing

About the role

We have an existing GST compliance module integrated via Quicko/Sandbox as our GSP. GSTR-1 filing and GSTR-2A/2B retrieval are complete and working in production. We need an experienced integrator to complete the GSTR-3B filing flow end to end.

Scope of work

• Complete the GSTR-3B flow: SAVE → summary generation → Proceed to File → offset liability → file with EVC/DSC
• Debug an existing request-context rejection on the offset-liability (RETOFFSET) call
• Handle electronic cash and credit ledger retrieval and ITC set-off logic per GSTN utilisation rules
• Implement asynchronous response handling and status polling
• Error handling, retry logic and logging for GSTN downtime
• Documentation and handover

Required

• Demonstrable prior experience filing GSTR-3B through GST APIs (not just GSTR-1 or e-invoicing)
• Hands-on with a GSP wrapper — Quicko/Sandbox, Masters India, Cygnet, IRIS, ClearTax or similar
• Solid understanding of GSTN authentication: OTP session tokens, app key / SEK / EK encryption, token expiry handling
• Familiarity with GSTN error codes and the RETOFFSET request structure
• [Your backend stack — e.g. PHP/Laravel, Node.js, Python/Django]

Good to have

• Experience with e-way bill or e-invoicing (IRP) integration
• Prior work on Indian accounting or ERP products

Pay: ₹10,000.00 - ₹20,000.00 per week

Application Question(s):

• Which GSP platforms have you worked with, and on which return types?
• Walk us through the offset-liability call — what is sent, and what must happen before it?
• Your availability and expected rate (hourly or fixed for the scope above)

Work Location: In person