SMS for accounting and tax advisory firms: deadlines that do not slip and signed engagements
· 3 min read
In an accounting firm, half of the invisible work is chasing people: the client who does not send the invoices, the one who does not know the quarter closes on the 20th, the one who “did not see the email” with the draft. And when something goes wrong, the awkward question is always the same: can you prove you told them in time?
The deadline reminder, to the whole portfolio in one call
“Reminder: we file your Q3 VAT by 20 October. We need your invoices before the 10th.” That SMS, sent to the 300 clients affected, is a single call to the API with burst sending — each client with their name and their deadline in the text — or a campaign from the dashboard if you would rather not program anything: you upload the file and that is it.
An SMS is read within minutes; your reminder stops competing with the promotions folder of the inbox.
The documentation request, on record
When the notice has consequences — surcharges, penalties, a closing of the books that never comes — the message is better certified: an evidence file with a timestamp that proves what was communicated, when and to which number. The day a client says “nobody told me”, the answer is a certificate, not an “I told you on the phone”.
Our honest view of its evidential value is explained without small print in how certified messaging works.
The engagement letter, signed on the phone
Onboarding a new client should not wait until they come by the office: the engagement letter signed by certified SMS reaches their phone, they read it and sign it with a one-time code. The document, the reading and the signature remain chained in a sealed evidence file. The same circuit works for one-off authorisations (filing a form, requesting a deferral, representing them in response to a notification).
How it is done, screen by screen: certified messaging step by step.
Three notices that are phone calls today and should be SMS
| Situation | The SMS that solves it |
|---|---|
| End of quarter | “We need your Q3 invoices before Friday the 10th” — in a burst, to the whole affected portfolio |
| Draft ready | “Your Q3 VAT comes out at €1,240 to pay. If you do not tell us otherwise, we will file it on Monday” — certified if silence has consequences |
| Document awaiting signature | “We have sent you the authorisation for the deferral: sign it from this link” — certified contract with OTP signature |
The difference from email is not only the open rate: each of these messages stays in your history with its status — sent, delivered, read, signed — which can be consulted per message or through the API, and exported if a case file needs it.
And if your firm uses its own software
The REST API does everything the dashboard does from your practice management software: individual sending, bursts of up to 5,000 notices in one call with safe retries, certificates and status queries. The typical integration —a deadline reminder triggered from your client database— is a few hours of work for your IT provider, and sandbox mode lets them test everything at no cost before touching anything real.
What it costs and how to start
A fixed price per message, a prepaid balance that does not expire, no lock-in: rates. Sandbox mode lets your IT provider integrate the API without spending anything.
- Create your account — test mode is activated when you verify your email.
- Upload your client portfolio or connect it through the API.
- Register your firm's name as a sender (Alias Registry guide): mandatory since 15-09-2026 to send under your brand.