Case study: taking the chasing out of a CA firm with n8n and WhatsApp

Chartered accountancy firms run on deadlines, and most of the work around a deadline isn’t accounting. It’s chasing — asking clients for documents, reminding them about due dates, answering the same five questions on WhatsApp, and updating a spreadsheet so the partner knows where things stand.

This is how I took most of that chasing off a firm’s staff with Practice Desk, built on n8n, WhatsApp and a small Next.js dashboard.

The problem

Before writing anything, I spent time with the people doing the work. The pattern was the same every filing season:

• Client questions arrived on WhatsApp and email, mostly repeats: “What documents do you need?”, “What’s my due date?”, “Did you receive my file?”
• Document collection was a manual loop: ask, wait, check, ask again.
• Reminders were sent by hand from a spreadsheet, so they were late when the office was busiest — exactly when they mattered most.
• The partner had no single view of which clients were blocked and why.

None of this needed a big new system. It needed the repetitive parts to run on their own, and one place to see the rest.

What I built

Replies on WhatsApp and email

An n8n workflow receives incoming messages, classifies them with a small LLM call (Groq, for speed), and answers the routine ones from the firm’s own information: document checklists, due dates per client, office hours. Anything that isn’t routine — fees, advice, complaints — goes straight to a person with the context attached.

Document collection

Each client has a checklist per filing. When a document arrives on WhatsApp or email, the workflow matches it to the client, files it, ticks the checklist, and if something is still missing, asks for exactly that item. Staff stop doing the “did we get it yet?” loop.

Filing reminders

Reminders go out on a schedule before each deadline, and stop automatically once the documents are in. Nobody has to remember to send them, and nobody gets reminded about something they’ve already sent.

One dashboard

A Next.js dashboard shows clients, upcoming deadlines, leads and invoices in one place. Google Sheets stays as the data layer the staff already understand, so there was no migration and no retraining on a new database. Each firm sees only its own data.

The result

Roughly 15 hours a week of replies, reminders and document chasing came off the staff. Just as important, reminders now go out on time during the busiest weeks — the period when the manual process used to break down.

What made it work

• Starting from the workflow, not the tool. Mapping the process with the staff showed that the expensive part was chasing, not filing.
• Keeping humans on the judgment calls. The automation answers routine questions and hands off everything else with context. Clients still talk to their accountant about anything that matters.
• Using what the team already trusted. Google Sheets as the data layer meant adoption on day one.
• Error alerts from the start. If a workflow fails, someone knows within minutes instead of discovering it at the deadline.

Could this work for your firm?

If your team spends more time asking for things than doing the work, the same pattern applies — accountants, clinics, agencies, property managers. Read how I choose between n8n, Zapier and Make, or send me a brief describing your current process.