How to connect
to HMRC
A step-by-step guide to linking your Government Gateway account to File MTD ITSA using HMRC’s secure OAuth 2.0 authorisation. The whole journey usually takes under five minutes.
Connection steps
From a new account to a live HMRC link — here is the flow you will follow inside File MTD ITSA.
Sign up
Create your File MTD ITSA account and choose the plan that fits how you want to file (self-serve or with accountant support).
Open Connect
From the Maintain area, tap Connect to HMRC (wording may say “Connect to HMRC Gateway”) to start the official OAuth journey.
Government Gateway
You are redirected to HMRC’s own site. Sign in with your Government Gateway user ID and password — we never see those credentials.
Authorise
Review the permissions and grant File MTD ITSA authority to submit MTD updates on your behalf. You can revoke this anytime from HMRC.
MTD ITSA is HMRC’s programme for reporting income and expenses digitally for sole traders, landlords, and other businesses in scope. You keep digital records, send quarterly updates, and complete an end-of-year declaration. Official overview: GOV.UK — Making Tax Digital for Income Tax.
Who should use this guide?
Use this page if you are a landlord or sole trader (or an accountant setting up a client) and you need to authorise File MTD ITSA so quarterly updates and year-end filings can reach HMRC. You already have or will create a Government Gateway account that matches the business you are putting onto MTD.
Before you start
Gather these so the connection is smooth:
- An active HMRC Government Gateway — create one from GOV.UK HMRC online services if needed.
- Your National Insurance number (NINO).
- Your Unique Taxpayer Reference (UTR) (Self Assessment letters or your HMRC account summary).
- Enrolment for Making Tax Digital for Income Tax (MTD ITSA) where required — if you are not sure, check your HMRC account or ask your accountant.
- A few minutes of quiet time: you will leave our site briefly to sign in on HMRC, then bounce back when you approve access.
Why OAuth matters
OAuth means HMRC issues a time-limited token to file MTD submissions. Your Gateway password never passes through our servers, and you can disconnect by revoking access in HMRC or using our reconnect flow.
What you will see
After authorisation you return to File MTD ITSA with a Connected status. You can then sync obligations, run tax estimates, file quarterly updates, and complete your end-of-year declaration when ready.
Detailed walkthrough
1. Register and log in
Create your account at our registration page, confirm your email, and sign in with the password you chose. Business details and identifiers (NINO, UTR) in our system should match what HMRC holds.
2. Open Maintain → HMRC
In the portal sidebar, open Maintain. Find the HMRC connection panel and choose the button to start the connection (e.g. Connect to HMRC Gateway). We will send you to HMRC’s production or sandbox URL depending on the mode you have selected.
3. Sign in on HMRC
Complete Government Gateway sign-in on HMRC’s pages. Review the consent screen: it lists what our software is allowed to do (for example submit quarterly updates). Confirm to issue the token.
4. Confirm back in File MTD ITSA
You should land back in the app with a success message and a live connection. If anything fails, see Common issues below or contact support with a screenshot of the error text (not your password).
After you are connected
- Pull your MTD obligations so due dates match HMRC.
- Draft and submit quarterly updates from the filing queue.
- Optional: trigger HMRC tax calculations to review estimates during the year.
- At year end: annual adjustments, then your final declaration when you are ready.
Token refresh and reconnecting
HMRC access tokens last a long time (typically up to 18 months). File MTD ITSA refreshes them in the background where possible. If a token expires — for example after long inactivity — the Maintain page will prompt you to reconnect; the OAuth flow is the same and usually finishes in a couple of minutes.
Sandbox vs production
Use sandbox to practise with test data and HMRC’s test users. Switch to production only when you are ready for real obligations. You can change mode from the Maintain / settings area where your administrator has exposed it.
Common issues
- Not enrolled for MTD ITSA: HMRC may block the link until your business is inside the MTD ITSA programme — complete enrolment in Gateway first.
- Access denied / insufficient authority: Wrong HMRC user, wrong business type selected, or consent not granted — retry and ensure you approve every scope HMRC shows.
- Invalid credentials on Gateway: Reset or check your ID and password directly on HMRC (we cannot see or reset them).
- NINO or UTR mismatch: Details in File MTD ITSA must align with the Gateway account you authorise.
- Browser blocked redirect: Allow pop-ups or third-party cookies temporarily for the HMRC domain; try another browser or private window.
- Stale connection after long break: Use Reconnect on Maintain and complete OAuth again.
Our team resolves most connection tickets within one business day — include any error reference HMRC shows (no passwords).
Related resources
- MTD ITSA guide — wider product walkthrough on the service.
- FAQ — billing, MTD rules, and account questions.
- Contact — reach the team if you are stuck on authorisation.
HMRC setup — FAQ
Quick answers about connecting to HMRC.