Terms of Service

Arcadeus is a financial management platform designed for UK sole traders and small businesses. It enables users to track income, expenses, and invoices, and to submit VAT returns and income tax returns directly to HMRC via the Making Tax Digital (MTD) API, including MTD for Income Tax Self Assessment (MTD ITSA).

By creating an account and using Arcadeus, you agree to these Terms of Service. If you do not agree, do not use the service.

Arcadeus is intended for use by individuals and businesses registered or operating in the United Kingdom. You must be at least 18 years old to create an account.

You are responsible for maintaining the security of your account credentials. You must not share your password or allow others to access your account. Notify us immediately at info@arcadeus.ai if you suspect unauthorised access.

We reserve the right to suspend or terminate accounts that violate these terms or that we reasonably believe are being used fraudulently.

Arcadeus integrates with HMRC's Making Tax Digital API to submit VAT returns on your behalf. By connecting Arcadeus to HMRC via the MTD authorisation flow, you:

• Authorise Arcadeus to act as your agent for the purpose of submitting VAT returns to HMRC.
• Confirm that you have reviewed and approve the VAT figures before initiating any submission.
• Accept full responsibility for the accuracy of the data submitted. Arcadeus transmits the figures you have entered; we do not independently audit or verify them.
• Acknowledge that submitted VAT returns cannot be recalled or modified through Arcadeus once accepted by HMRC. Any amendments must be made directly with HMRC.

You can disconnect Arcadeus from HMRC at any time via Tax Settings. Disconnecting removes our authorisation to submit future returns but does not affect returns already submitted.

If you use Arcadeus for MTD ITSA, you authorise us to act on your behalf for the following interactions with HMRC's API:

• Quarterly updates: submitting cumulative income and expense summaries for each quarter of the tax year for your self-employment or UK property business sources.
• End of Period Statements (EOPS): confirming the accuracy of your annual income and expense figures for each business source at the end of the tax year. By checking the confirmation box and submitting an EOPS, you are making a legal declaration that the figures are correct to the best of your knowledge.
• Final Declaration: crystallising your Self Assessment income tax liability for the tax year. This is a legally binding submission. Once a Final Declaration is accepted by HMRC, it cannot be reversed through Arcadeus. Any subsequent corrections must be made directly with HMRC.
• Tax calculations: retrieving an HMRC-generated estimate of your income tax liability. These calculations are based only on data HMRC have received and are provided as estimates only — they may change if HMRC receive additional information.

For MTD ITSA you must provide your National Insurance number (NINO). This is stored securely and used solely to identify you with HMRC's APIs.

You retain full responsibility for the accuracy of all figures submitted. Arcadeus transmits what you have entered and confirmed; we do not independently verify your income or expense data.

Not all income types or tax situations are supported by Arcadeus. For a list of compatible MTD ITSA software and the income types each supports, refer to HMRC's compatible software list.

HMRC's MTD programme requires all software that interacts with their API to transmit fraud prevention headers with every request. These headers include technical metadata about your device and network connection (such as IP address, browser type, screen size, and timezone).

By using Arcadeus's MTD features, you consent to the collection and transmission of this metadata to HMRC as required by law. This is a statutory obligation and cannot be disabled. Full details are in our Privacy Policy.

You agree not to use Arcadeus to:

• Submit false, fraudulent, or misleading information to HMRC.
• Attempt to circumvent HMRC's fraud prevention systems.
• Access or attempt to access other users' data.
• Reverse engineer, copy, or redistribute the Arcadeus platform.
• Use the service in any way that violates UK law.

Our collection and use of your personal data is governed by our Privacy Policy, which forms part of these Terms of Service.

We aim to keep Arcadeus available at all times but do not guarantee uninterrupted access. We may update, modify, or discontinue features with reasonable notice where possible.

We reserve the right to update these Terms of Service. We will notify you of material changes by email or in-app notice. Continued use of Arcadeus after changes take effect constitutes acceptance of the updated terms.

To the fullest extent permitted by law, Arcadeus shall not be liable for any indirect, incidental, or consequential loss arising from:

• Errors or inaccuracies in VAT returns or income tax submissions based on data you provided.
• Penalties, interest, or surcharges levied by HMRC as a result of your submissions.
• Any reliance on HMRC tax calculations retrieved via Arcadeus, which are estimates only.
• Temporary unavailability of the service or HMRC's API.

Nothing in these terms limits liability for death or personal injury caused by negligence, fraud, or any other liability that cannot be excluded under English law.

These Terms of Service are governed by the laws of England and Wales. Any disputes arising from the use of Arcadeus shall be subject to the exclusive jurisdiction of the courts of England and Wales.

For questions about these terms, contact us at info@arcadeus.ai.