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GST invoicing · service businesses · India

Invoicing Software for Service Businesses

Service businesses don’t sell stock — they sell time and expertise, and they bill on SAC codes, get TDS deducted by their clients, and live on receivables. A consultant runs retainers, an agency passes through ad spend, a transporter bills under reverse charge, an IT firm exports under an LUT. 399Apps (Nidhi Books) handles all of it — GST invoicing, TDS reconciliation and AR aging in one system — for a flat ₹399/month, unlimited users.

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Flat ₹399/month · Unlimited users · Cloud or self-hosted · No card required

Pick your service business

Each page shows how 399Apps invoices the way your practice actually bills — the right SAC, the right TDS, the right receivables view — not a generic invoice form.

Built for how service businesses bill

  • ✓SAC-coded GST invoices with place-of-supply
  • ✓Quote / proposal → invoice conversion
  • ✓Retainer, milestone and advance billing
  • ✓Zero-rated export invoices under LUT
  • ✓TDS-on-receipts (194J / 194C), 26AS-ready
  • ✓AR Aging + client-wise outstanding
  • ✓GSTR-1 / GSTR-3B-ready CSV exports
  • ✓Unlimited users — the whole team invoices
FAQ

Invoicing software for service businesses — FAQ

What is the best invoicing software for a service business in India? +
The best fit depends on how you bill — a consultant runs monthly retainers with 194J TDS deducted, an agency mixes retainers with pass-through spend, a transporter bills freight under reverse charge, an IT firm exports under an LUT. 399Apps (Nidhi Books) handles all of these with SAC-coded GST invoices, place-of-supply, TDS-on-receipts and AR aging in one system for a flat ₹399/month with unlimited users, cloud or self-hosted.
How much does invoicing software cost in India? +
399Apps is a flat ₹399/month for your first app and ₹99/month for each additional app or add-on — the same price across India, with no per-user licence and no per-invoice fee. Most invoicing tools charge per seat or per invoice; 399Apps does not.
Does 399Apps handle GST and TDS for service invoices? +
Yes. Service invoices carry the correct SAC code, place-of-supply drives CGST/SGST vs IGST, and exports can be raised as zero-rated supplies under an LUT. When your clients deduct TDS (194J or 194C), 399Apps records it section-wise so your books reconcile to Form 26AS at year-end.
Can I track receivables and follow up on overdue invoices? +
Yes. Every invoice has a due date, and AR Aging buckets receivables into current, 1–30, 31–60, 61–90 and 90+ days overdue with client-wise outstanding, so slow payers surface before the money is really late.
Is 399Apps available on the cloud or self-hosted? +
Both. Run it fully managed on the 399apps cloud with daily backups and an India data region, or self-host on your own server for complete data ownership. The same invoicing and GST features work either way.
Try 399Apps

Affordable invoicing software for every service business — from ₹399/month

GST invoicing, TDS reconciliation and receivables in one system, with unlimited users. Start your free 14-day trial — no card required.

Start your free trial See pricing