Terms of Service
Last updated: 3 April 2026
1. Service Description
OpenCT (“the Service”) is a cloud-based Corporation Tax filing platform operated by Lightweight Integration Ltd (“we”, “us”). The Service enables UK businesses to prepare, validate, and submit CT600 returns, SA100 personal tax returns, and VAT returns to HMRC.
2. Eligibility
The Service is available to UK-registered companies and their authorised agents. You must be at least 18 years old and have authority to act on behalf of the company you register.
3. Account Responsibilities
You are responsible for maintaining the confidentiality of your account credentials and Government Gateway details. You must notify us immediately of any unauthorised access.
4. Accuracy of Information
You are responsible for the accuracy of all financial data entered into the platform. While OpenCT provides automated validation (BVR business rules, XML structure, iXBRL compliance), the legal responsibility for the accuracy of your tax return rests with you and your company’s directors.
5. HMRC Submissions
When you submit a return via OpenCT, we transmit it to HMRC on your behalf using the Government Gateway credentials you provide. Submissions are final once acknowledged by HMRC. Amendments must be filed as a separate amended return.
6. Pricing
Community (Free): Unlimited computations and validations. HMRC submission not included.
Standard (£39/year): Full HMRC filing for one company.
Professional (£99/year): Up to 10 companies, team collaboration, priority support.
Enterprise (custom): Unlimited companies, white-labelling, API access, dedicated support.
7. Limitation of Liability
OpenCT is provided “as is”. We do not guarantee that HMRC will accept every submission. Our liability is limited to the fees paid for the Service in the 12 months preceding any claim. We are not liable for penalties, interest, or surcharges imposed by HMRC as a result of errors in your data.
8. Intellectual Property
OpenCT is open-source software. The source code is available under the terms of the applicable open-source licence. Your financial data remains your property at all times.
9. Termination
You may close your account at any time via Settings. Upon termination, your data will be deleted in accordance with our Privacy Policy. We may suspend or terminate accounts that violate these terms or engage in fraudulent activity.
10. Governing Law
These terms are governed by the laws of England and Wales. Any disputes shall be subject to the exclusive jurisdiction of the courts of England and Wales.
11. Contact
Lightweight Integration Ltd
Email: legal@openli.ai
Director: Zhong Li