Multi-Client MTD VAT Software for Accountants (2026)

What you need to file VAT for clients

HMRC sets out the steps for agents using Making Tax Digital for VAT:

1. Get compatible software that can file for your clients. Check it is on HMRC's software finder.
2. Create an agent services account. This is different from the old HMRC online services for agents account.
3. Ask each new client to authorise you for Making Tax Digital for VAT.
4. Connect your software to HMRC so it can file for the clients who have authorised you.
5. Manage your clients' details online once they have authorised you.

HMRC has already signed up VAT-registered businesses to Making Tax Digital, unless they are exempt, so you no longer need to sign clients up yourself.

The agent services account

The agent services account is where you manage client authorisations for Making Tax Digital services, including VAT. You create it with a Government Gateway user ID, and it is separate from any older agent account you may have.

Since March 2023 agents can no longer copy VAT clients across from the old agent account. Clients who have not authorised you in your agent services account need to authorise you again. See HMRC's guide to getting an agent services account.

How a client authorises you for VAT

1. In your agent services account, select Ask a client to authorise you and create an authorisation request.
2. Send the link to your client.
3. Your client signs in with their own Government Gateway details and accepts the request before the link expires.
4. Once accepted, you can view the client's VAT details and file their returns through your software.

If HMRC rejects a return with "client or agent not authorised", the authorisation is missing or has been removed, or the software was connected with a sign-in that cannot act for that VAT number. See what HMRC checks before accepting a VAT return.

Filing many clients without missing a deadline

• Know every period: clients have different VAT stagger periods, and some file monthly. Pull each client's open periods from HMRC rather than keeping your own list.
• Work by due date: each return and payment is usually due 1 calendar month and 7 days after the period ends.
• Chase records early: ask clients for their figures as soon as a period ends, not the week of the deadline.
• Check before you send: boxes that do not add up, or pence in Boxes 6 to 9, are the most common rejections.
• Keep the receipt: store HMRC's receipt reference for every client return.

Each late return earns the client a penalty point, so a missed deadline costs your client, not just your time. See how VAT penalty points work.

What to look for in multi-client VAT software

Clients who keep records in spreadsheets

Many small clients keep their VAT records in Excel or Google Sheets. That is allowed under Making Tax Digital, as long as the figures reach the return digitally. With bridging software you lay out each client's nine box totals in a CSV and upload it, so the client keeps their spreadsheet and you file from it. See how to submit VAT from Excel or CSV.

How Swift VAT Pro works for practices

1. Add each client company to your account and connect it to HMRC with a Government Gateway sign-in that can act for that VAT number.
2. See each client's open periods and due dates from HMRC, with their VAT liabilities and payments.
3. Upload the nine box totals as a CSV. Box 3 and Box 5 are worked out, and every box is checked against HMRC's rules.
4. Submit and keep HMRC's receipt. Any HMRC error, including "not authorised", is explained in plain English.
5. Reminder emails arrive 4 days and again 3 days before each due date.
6. Add staff logins so more than one person can file.

Swift VAT Pro is bridging software. It files VAT returns. It does not do bookkeeping, invoicing or bank feeds.

Plans for practices

• Small Practice, £20 a month or £200 a year: up to 20 companies and 3 users.
• Agent, £50 a month or £500 a year: up to 100 companies and 5 users.
• Enterprise, £100 a month or £1,000 a year: unlimited companies and 10 users.

There is no charge per return on these plans. Every plan has a 7-day free trial with no card needed. See the pricing page.

Final thoughts

Get your agent services account in place, make sure every client has authorised you for VAT, and use software that pulls each client's periods from HMRC. Then filing for many clients becomes a routine list worked by due date, not a scramble at the end of each month.

Disclaimer: This guide gives general information, not advice for your practice. Check HMRC's guidance for agents for the latest steps.