SmartScanit MTD — sandbox harness

Prototype. Points at the HMRC sandbox. Not for production data.

🌍 LanguageSense™your tax, explained in your own language
0 · Create a sandbox test user

Generates a fake individual (Government Gateway login + NINO) to log in with at step 1. Do this once and keep the details.

1 · Connect to HMRC with your own Government Gateway

You log in with your own Government Gateway account and give this software permission to send YOUR figures to HMRC. Nobody files for you — you review and submit your own quarterly updates. The callback shows the access token — copy it into steps 2 and 3.

Connect to HMRC →
2 · Check your quarterly obligations

See which quarterly update periods HMRC is expecting from you, and which are still open.

3 · Review and submit your own quarterly update

Check your cumulative (year-to-date) figures below, then submit your own quarterly update to HMRC. Figures are totals so far this tax year, not just this quarter.

Finds your Business ID and income sources held by HMRC.

You are submitting your own figures to HMRC (sandbox). Review them first — you stay in control.

4 · Work out your tax

Ask HMRC to calculate your tax from the figures you have submitted, then view the result. During the year, use the normal in-year calculation; tick the box below when you are ready to finalise your year.

5 · Final declaration

This is your legal declaration to HMRC that the information you have given is correct and complete to the best of your knowledge. You submit it yourself — check your calculation in step 4 first.

⚠ This is the binding year-end step. Once submitted, your tax year is finalised (crystallised). Only submit when you are sure.

🛠 Developer check · fraud-prevention headers

For SmartScanit staff: checks that the technical headers this software must send to HMRC by law are complete and accurate. Clients don't need this step.

Privacy & what we send to HMRC · Support