// build_guide
// How to build GST Filing Automation for Indian Freelancers
GST compliance is a recurring pain for 10M+ Indian freelancers and SMEs. A SaaS that auto-pulls invoices from accounting tools and pre-populates GSTR-1/3B filings can charge ₹499–₹999/month with very low churn. NestJS handles the complex computation logic cleanly; PostgreSQL stores filing history with full audit trail. Razorpay is mandatory for INR subscription billing.
Complexity 7/10SaaS
// recommended_stack
FrontendNext.js (App Router)
BackendNestJS
DatabasePostgreSQL
AuthSupabase Auth
HostingVercel + Railway
ExtraRazorpay Subscriptions
ExtraGST Portal Sandbox API
ExtraResend (email receipts)
// cost_and_timeline
USD min
$14,000
USD max
$22,000
INR min
₹13.1L
INR max
₹20.5L
Typical SaaS projects cost $1,800–$5,000 USD and take 6–8 weeks with an Indian dev team. See the full cost guide →
// timeline_breakdown
2 weeksAuth, onboarding & GSTIN verification
4 weeksInvoice ingestion & tax computation engine
3 weeksGST portal API integration & filing flow
2 weeksSubscription billing, reminders & polish
// mvp_features[]
## What to build in the MVP
—GSTIN registration and profile setup
—Invoice upload (CSV, Tally XML, manual entry)
—Automatic IGST / CGST / SGST computation
—GSTR-1 and GSTR-3B draft generation
—One-click filing via GST portal sandbox
—Email + SMS reminders for filing deadlines
// risk_flags[]
## Engineering risks to plan for
!GST portal API has rate limits and frequent downtime windows — build a retry queue from day one.
!Tax logic changes with every budget; architect the computation engine to be rule-driven, not hardcoded.
!GSTIN validation requires the GSTN sandbox, which needs a formal onboarding — start the registration process in week 1.
✦ Get a scope tailored to your idea
This scope was auto-generated from a real founder's inputs. Run the estimator with your specific requirements — free, no sign-up, results in 2 minutes.
// related_resources