The GST invoice that never got paid
Here's a scene I bet you know too well. You finish a phase. You send the invoice on WhatsApp as a PDF. The client says "received, will process." Then nothing. Three weeks later you're texting "just a gentle reminder" for the fourth time, feeling like a collection agent instead of a designer.
The problem isn't the client being difficult. The problem is the gap between "here's your invoice" and "here's how you pay it." When those are two separate steps, invoice on WhatsApp, then bank details in a follow-up message, then the client hunting for their card or IMPS app, every gap is a place the money stalls.
So let me walk you through how to close that gap. One flow: raise a proper GST invoice, attach a Razorpay payment link to it, and let the client pay by tapping once. This is exactly how it works inside Designa, but the principles hold whatever you use.
Why the invoice and the payment link have to travel together
Think about how your client actually pays. They open your message on their phone, between two other things. If they have to do work, save your account number, switch to their banking app, type the amount, get the IFSC right, most people just put it off. "I'll do it tonight." Tonight becomes next week.
Now imagine the invoice arrives with a button that says Pay Now. They tap it. UPI, card, netbanking, whatever they prefer opens right there. Thirty seconds, done. You get a notification. No account numbers, no typos, no follow-up.
That's the whole game. You're not chasing harder, you're removing friction. And Razorpay is the right rail for this in India because it handles UPI, cards, netbanking and wallets in one link, and the money lands in your bank account with a clean settlement report you can actually reconcile later.
Step 1: Get the invoice itself right first
Before you attach any payment link, the invoice underneath has to be a real GST invoice. A payment link on a sloppy invoice just gets you paid faster on a document your CA will reject at filing time. I've written a full breakdown on this in How to Raise a GST-Compliant Invoice for Design Work, but the short version, a proper tax invoice for a design studio needs:
- Your studio's legal name, address and GSTIN
- A unique, sequential invoice number (no gaps, no repeats, GST cares about this)
- Invoice date and the client's name, address, and GSTIN if they have one
- Description of what you're billing, design fees, supervision, a procurement item, per room or per phase
- The correct HSN or SAC code (interior design services usually sit under SAC 9954 / 998391 depending on what exactly you're billing)
- Taxable value, then the tax split: CGST + SGST if the client is in your state, IGST if they're in another state
- The total in figures, and ideally in words
Get the place-of-supply logic right, because that's what decides CGST+SGST versus IGST. A studio in Bengaluru billing a client with a Mumbai billing address is an inter-state supply, that's IGST, not CGST+SGST. Software that knows the client's state should pick this automatically. If you're doing it by hand in Excel, this is the line item people get wrong most often.
Step 2: Turn your approved quote into the invoice
You almost never start an invoice from scratch. You start from a quote the client already approved. The BOQ is done, the client signed off on the modular kitchen, the false ceiling, the loose furniture. That approved scope IS your invoice, you shouldn't be re-typing it.
The clean way is: quote gets approved, you convert it to an invoice in one action, the line items and amounts carry over, GST gets applied on top, and you're ready to send. No re-keying, no "wait, did I quote 1,80,000 or 1,85,000 for the wardrobes?" I go deep on this exact conversion in How to Turn a Quote Into a GST Invoice in Minutes, it's the single biggest time-saver in the whole billing cycle.
Inside Designa this is literally a button on the approved quote. It becomes a GST invoice with the tax split already calculated, your invoice number auto-incremented, ready to attach a payment link to.
Step 3: Attach the Razorpay payment link
This is the step that changes everything. Once your invoice is finalised, you generate a Razorpay payment link tied to that specific invoice amount. You connect your Razorpay account once, takes a few minutes, you'll need your Razorpay Key ID and Key Secret from the Razorpay dashboard, and after that every invoice can carry its own link.
The link is smart. It knows:
- The exact amount due, including GST, pulled from the invoice
- Which invoice and which client it belongs to, so when payment comes in you know what it settled
- What happens after payment, the invoice marks itself paid, you get pinged
When the client pays, Razorpay confirms it back to the system automatically. The invoice flips from "sent" to "paid" on its own. You are not manually ticking things off or asking your accountant "did the Sharma payment come in?" The status is just correct.
Step 4: Send it where the client actually is
An invoice that sits in an email the client never opens is worthless. Send it where they'll see it, WhatsApp, mostly. The invoice PDF plus the pay link, in one message, on the app they check forty times a day.
With a branded client portal it's even cleaner: the client logs into your studio's portal, sees the invoice, sees the balance, and pays right there. No PDF floating around, no "can you resend that invoice from March." It lives in one place with a Pay button next to it. That portal is also where they've been approving mood boards and specs, so paying you is just one more thing in a space they already trust.
Step 5: Handle advances properly, this is where studios leak money
Design work runs on advances. Booking advance, phase advances, milestone payments. And advances are exactly where GST and cash tracking get messy. You collect ₹2,00,000 as a booking advance, GST is due on that advance the moment you receive it, even though no work is delivered yet. Miss that and you've got a compliance gap. Collect it and forget to adjust it against the final invoice, and you've either double-charged the client or under-billed yourself.
I wrote a whole piece on this because it trips up so many studios, How to Handle Client Advances and GST the Right Way. The Razorpay flow helps here too: you raise a payment link for the advance itself, it's recorded as an advance against that project, and when you raise the final invoice the advance is already sitting there waiting to be adjusted. Nothing gets lost between "they paid something in January" and "what's the balance now."
Untracked advances are one of the quietest ways money disappears from a studio, I broke down the full pattern in Untracked Advances: The Payment Leak Nobody Notices. If you take advances and you're not linking them to invoices, you are almost certainly leaving money on the table without knowing it.
Step 6: Let it flow into your books
Payment collected, invoice marked paid, now it has to reach your accounts. If your accountant is re-typing every invoice into Tally at month-end, that's hours of duplicate work and a fresh chance for numbers to drift between what you billed and what your books show.
The fix is sync. Invoices, payments and the GST split flow into Tally or Zoho Books automatically, so your billing and your books agree without anyone copy-pasting. Your CA files from clean data. You spend month-end doing design work instead of data entry.
The whole flow, end to end
Put it together and here's what one payment cycle looks like when the invoice and the payment travel as one thing:
- Client approves the quote in the portal
- You convert it to a GST invoice in one tap, tax split done, invoice number assigned
- A Razorpay link is attached, matched to the exact amount
- It goes out on WhatsApp or sits in the client portal with a Pay button
- Client taps, pays by UPI or card, invoice marks itself paid
- The entry syncs into Tally or Zoho, your books stay clean
No account-number messages. No fourth reminder. No wondering whether the payment came in. The friction that used to sit between "invoice sent" and "money received" is just gone.
You can see this exact flow running end to end at demo.designa.work, raise a test invoice, attach a link, watch it mark itself paid. When you're ready to run your real studio billing on it, the founding offer is one flat ₹2,299 + GST per year for the whole studio, up to 10 members, unlimited client logins, and we'll migrate your existing data and set up your invoicing for you.
Stop being your own collection agent. Grab the offer at go.designa.work and get your next invoice paid before you've finished your chai.