Skip to content
399apps.com logo 399apps.com
Get a demo
GST invoicing · service businesses · Consultants

Invoicing Software for Consultants & Advisory Firms

Retainer and milestone invoices, TDS reconciled — without a per-seat suite.

For Consultants businesses

Consulting income arrives as monthly retainers and milestone fees, and almost every corporate client deducts TDS before they pay you. The job is to raise a clean GST invoice, track what is still outstanding client-by-client, and reconcile the tax your clients withheld — not to manage a warehouse.

Start your free 14-day trial Get a free demo

Flat ₹399/month · Unlimited users · No card required · Cancel anytime

How consultants billing works

Consultants bill against engagements: a fixed monthly retainer, a milestone on a project, or an hourly block. In 399Apps (Nidhi Books) you raise a professional GST invoice with the right SAC code and place-of-supply, convert an accepted quote straight into an invoice, and set a due date so every retainer follows the same cycle. AR Aging then shows exactly which clients are current, 30, 60 or 90+ days overdue.

GST & TDS, handled right

Consulting is a service under SAC 9983 (management / advisory), taxed at 18% GST with intra- vs inter-state CGST/SGST/IGST split by your client’s place of supply. Corporate clients deduct TDS at 10% under Section 194J on your fees — 399Apps captures TDS-on-receipts section-wise so your books line up with Form 26AS at year-end instead of a March scramble.

The billing problems it solves

Different service, same trap — money earned that never quite gets billed or collected. Here's what 399Apps keeps straight for consultants & advisory firms:

TDS you can’t reconcile

Clients deduct 194J but you lose track — 399Apps records TDS-on-AR by section so 26AS matches your books.

Retainers that slip

Due dates on every retainer invoice and AR-aging buckets show which clients have gone past 30/60/90 days.

Wrong place-of-supply

Out-of-state clients need IGST, not CGST/SGST — 399Apps splits it correctly on every invoice.

Quote-to-invoice rework

Send a quote, and convert the accepted one into an invoice without re-keying the scope or the numbers.

What you get

  • ✓GST invoices with SAC 9983 & place-of-supply
  • ✓Quote / proposal → invoice conversion
  • ✓Due dates + AR Aging (current / 30 / 60 / 90+)
  • ✓TDS-on-receipts, section-wise (194J), 26AS-ready
  • ✓Client-wise outstanding & statements
  • ✓Unlimited users — partners and associates included

One flat price — the whole team invoices

Most invoicing tools charge per user or per invoice, so growing your practice grows the bill. 399Apps is a flat ₹399/month for your first app and ₹99/month for each additional app — GST invoicing, TDS reconciliation and receivables in one system, unlimited users, cloud or self-hosted. Adding partners, associates or account managers never raises the price.

Start free trial See full pricing
More service businesses

Invoicing software for other service businesses

Keep reading

Guides & comparisons

FAQ

Invoicing software for consultants & advisory firms — FAQ

Does 399Apps work for consultants & advisory firms? +
Yes. 399Apps (Nidhi Books) is built for the way consultants & advisory firms actually invoice. Consultants bill against engagements: a fixed monthly retainer, a milestone on a project, or an hourly block. In 399Apps (Nidhi Books) you raise a professional GST invoice with the right SAC code and place-of-supply, convert an accepted quote straight into an invoice, and set a due date so every retainer follows the same cycle. AR Aging then shows exactly which clients are current, 30, 60 or 90+ days overdue.
How does GST and TDS work for consultants businesses in 399Apps? +
Consulting is a service under SAC 9983 (management / advisory), taxed at 18% GST with intra- vs inter-state CGST/SGST/IGST split by your client’s place of supply. Corporate clients deduct TDS at 10% under Section 194J on your fees — 399Apps captures TDS-on-receipts section-wise so your books line up with Form 26AS at year-end instead of a March scramble.
How much does invoicing software cost for a consultants business? +
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. A solo professional and a growing consultants firm pay the same base price.
Can I track who still owes me and follow up on time? +
Yes. Every invoice carries a due date, and AR Aging buckets receivables into current, 1–30, 31–60, 61–90 and 90+ days overdue with per-client outstanding — so you chase the slippers before the money is really late, without a manual ledger.
Can I run it on the cloud or on my own server? +
Both. Run 399Apps fully managed on the 399apps cloud with daily backups and an India data region, or self-host it on your own server for complete data ownership. The same invoicing and GST features work either way.
Try 399Apps

Affordable invoicing software for consultants & advisory firms — 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