Licences and credits
Last updated: 13 September 2026
MTDFox is built on open-source software and open data. This page lists what we use, under which licence, and the credit each one asks for. The MTDFox name, logo, design and written content are © BYTE HAVEN LTD and may not be reused without permission.
Your licence to use MTDFox
Your account gives you a personal, non-transferable licence to use the service for your own tax affairs (or, for an invited accountant, those of the client who invited you) under our terms of service. The records you enter remain yours; you can export them at any time.
Open data
| What | Used for | Licence |
|---|---|---|
| IP Geolocation by DB-IP | Country and city of visitors, for our own traffic statistics | CC BY 4.0 |
| HMRC guidance and forms (SA103, SA105, MTD guidance) | Category names, box references, thresholds and deadlines quoted in guides | Open Government Licence v3.0, © Crown copyright |
Fonts
| Font | Author | Licence |
|---|---|---|
| Inter | Rasmus Andersson | SIL Open Font License 1.1 |
| Fraunces | Undercase Type | SIL Open Font License 1.1 |
Software
| Component | Licence |
|---|---|
| Python | PSF License |
| FastAPI, Starlette, Uvicorn, httpx | BSD 3-Clause / MIT |
| Jinja2, itsdangerous | BSD 3-Clause |
| cryptography | Apache 2.0 / BSD |
| python-multipart, qrcode, maxminddb, beautifulsoup4 | Apache 2.0 / BSD / MIT |
| stripe-python | MIT |
| Tailwind CSS | MIT |
| SQLite | Public domain |
Full licence texts are available on request from info@mtdfox.co.uk.
Services we rely on
Payments are processed by Stripe Payments UK Ltd. Bank data is retrieved by GoCardless Ltd, authorised by the Financial Conduct Authority as an Account Information Service Provider (FRN 597190). Submissions go to HM Revenue & Customs through its Making Tax Digital APIs. Each is used under its own terms, linked from the page where you meet it.
Trade marks
HMRC, Making Tax Digital and GOV.UK are marks of the UK Government. Stripe, GoCardless and the bank names shown when you connect an account belong to their owners. MTDFox is not endorsed by any of them; our HMRC recognition status is stated on the legal notice.