Terms of Service

Welcome to DigiSim.io! These Terms of Service ("Terms") govern your use of the DigiSim.io website, services, and applications (collectively, the "Service"), operated by DigiSim Technology Ltd ("we," "us," or "our").

Please read these Terms carefully before using our Service. By accessing or using the Service, you agree to be bound by these Terms. If you disagree with any part of the terms, then you may not access the Service.

1. License Overview (Quick Summary)

Free Tier: DigiSim offers a free tier with access to selected lessons and simulator components at no cost, as currently configured. Circuits you create are saved locally in your browser.

SimCast Sets: Individual themed lesson bundles available as one-time purchases. Each purchase grants access to the purchased content for as long as the Service remains available.

Complete Bundle: A one-time purchase granting access to all SimCast Sets and all simulator components for as long as the Service remains available.

No Subscriptions: All paid plans are one-time purchases. There are no recurring charges. You pay once and retain access under the terms described herein.

2. Description of Service

DigiSim.io provides an interactive, web-based platform for learning, creating, and simulating digital logic circuits. The Service includes SimCast (narrated simulation playback lessons), a circuit simulator, local browser-based storage for user-created circuits, and related educational tools. Circuits are stored locally in your browser's IndexedDB; you may export them as .digi files at any time. The Service is designed for educational purposes to help students, hobbyists, and professionals understand the principles of digital electronics.

3. User Accounts

Account Creation: To access most features of the Service, including saving and managing circuits, you must register for an account. You agree to provide accurate, current, and complete information during the registration process.

Account Responsibility: You are responsible for safeguarding your account credentials and for any activities or actions under your account. You agree to notify us immediately upon becoming aware of any breach of security or unauthorized use of your account.

One Account Per Person: Each user may maintain only one account. Creating multiple accounts to circumvent usage limits, abuse free tier allowances, or exploit promotional offers is prohibited.

Age Requirement: The Service is available to users of all ages. However, if you are under the age of 13, you must have the consent of a parent or legal guardian to use the Service.

Third-Party Authentication

Google Sign-In:

• We offer Google Sign-In as a convenient authentication option
• By using Google Sign-In, you agree to comply with Google's Terms of Service
• We only request access to your basic Google profile information (email, name, profile picture)
• You can manage or revoke DigiSim.io's access to your Google account at any time through your Google Account settings

Authentication Security:

• We do not store your Google password or access your Google services beyond authentication
• Your Google account credentials are managed entirely by Google's secure infrastructure
• We use OAuth 2.0 industry-standard protocol for secure authentication

Account Linking:

• If you create an account with Google Sign-In, your DigiSim.io account will be linked to your Google email address
• You are responsible for maintaining the security of your Google account
• If your Google account is compromised, please immediately change your Google password and contact us

4. Purchase Terms and Access Rights

Nature of Purchase

All purchases on DigiSim.io grant a non-exclusive, non-transferable, revocable license to access the purchased digital content through the Service. You are purchasing a right to access content — not ownership of the underlying intellectual property, source code, or educational materials.

Access Duration

Purchased content (SimCast Sets and Bundles) remains accessible to you for as long as the Service is operational and your account is in good standing. Access is subject to these Terms and may be revoked for violations. We do not guarantee perpetual or indefinite access. The Service is provided on a commercially reasonable, best-effort basis.

Free Tier

The free tier provides access to selected lessons and components as currently configured. Free tier features and availability are subject to change at any time at our sole discretion, with or without notice. We may modify, reduce, or discontinue free tier offerings as our business evolves.

No Transfer or Resale

Purchased licenses are personal to the account holder and may not be transferred, resold, shared, or assigned to another person or entity. Account credentials must not be shared with others.

Future Content

Purchased Sets include the content available at the time of purchase. We may, at our sole discretion, add new lessons or features to existing Sets — however, we are under no obligation to do so. New Sets or products released after your purchase are separate offerings and not included.

Tier Access, Not Fixed Catalog

A tier purchase grants ongoing access to the current and future contents of that tier. The catalog is actively maintained: we regularly add new SimCast lessons, components, templates, and features. We may also replace, merge, or (rarely) withdraw individual items — for example, to correct defects, improve pedagogy, consolidate overlapping content, or address licensing concerns. Your purchase grants access to the tier, not to any specific item in the catalog as of the date of purchase. No specific SimCast lesson, component, template, or feature is guaranteed to remain available in its current form, name, style, or pacing.

Pricing Changes

We reserve the right to modify pricing for any products or services at any time. Price changes do not affect previously completed purchases. Any promotional or introductory pricing is temporary and may be withdrawn at any time.

Payment Processing

We use Stripe as our payment processor. By making a purchase, you agree to Stripe's terms of service. We are not responsible for payment processing errors, declined transactions, or issues caused by your payment provider.

Refunds

For our full refund policy, please refer to our Refund Policy.

5. User-Generated Content

Your Content: You retain all ownership rights to the digital circuits, designs, and other content you create or save while using the Service ("User Content"). Circuits are stored locally in your browser's IndexedDB and are not uploaded to our servers. You can export them as .digi files at any time to back them up or move them to another device.

License to Us: To the extent any User Content is transmitted to our servers (for example, via SimCast playback or template loading), you grant us a worldwide, non-exclusive, royalty-free license to use and reproduce that content solely to operate and improve the Service.

Exported Files: .digi files you export are your own data. You may store, share, and distribute them freely. We have no claim over files you export and store outside the Service.

Responsibility: You are solely responsible for your User Content and represent that you have all necessary rights to use any content you design within the Service. You must not attempt to store content that infringes third-party intellectual property rights.

6. Resources and Fair Use Policy

DigiSim.io provides computing resources for circuit simulation and SimCast playback. Circuits are stored locally in your browser — there are no server-side circuit storage quotas. These server resources are shared among all users, and fair use is required to maintain service quality for everyone.

Local Storage

Circuits save to your browser's local IndexedDB storage. There are no server-imposed circuit quotas. You may export unlimited .digi files to your own storage at any time.

Prohibited Activities

You agree not to use the Service for:

• Bulk/Automated Creation: Using scripts, bots, crawlers, or automation tools to generate, upload, or download massive quantities of files or data.
• Non-Circuit Data: Attempting to store non-circuit data, binary files, or data unrelated to logic simulation (e.g., using project metadata fields as a general-purpose file host).
• Excessive Load: Creating an abnormal volume of projects, simulations, or API requests that exceeds reasonable human operation (e.g., hundreds of creations per day).
• Resource Exploitation: Using SimCast playback, audio generation, or simulation resources in a manner designed to consume excessive server resources.
• Credential Sharing: Sharing account credentials with others to allow multiple people to access purchased content through a single account.
• Content Scraping: Systematically downloading, copying, or redistributing SimCast lesson content, narration audio, or simulation data.

Enforcement

If we detect usage patterns consistent with abuse, bot activity, credential sharing, or resource exploitation, DigiSim reserves the right to — at our sole discretion and without prior notice — throttle API access, suspend write permissions, restrict account features, or permanently terminate the account. Accounts terminated for policy violations are not eligible for refunds.

Monitoring

We reserve the right to monitor usage patterns, storage consumption, and API activity for the purpose of enforcing these Terms, maintaining service quality, and detecting abuse. We will not access the content of your private circuits except as required for technical maintenance or legal compliance.

7. Acceptable Use Policy

You agree not to misuse the Service or help anyone else to do so. You agree not to:

• Probe, scan, or test the vulnerability of any system or network
• Breach or otherwise circumvent any security or authentication measures
• Access, tamper with, or use non-public areas of the Service, its systems, or its infrastructure
• Interfere with or disrupt any user, host, or network, including by sending viruses, overloading, or flooding the Service
• Use the Service for any illegal or unauthorized purpose
• Reverse-engineer, decompile, disassemble, or attempt to derive the source code of the Service
• Create derivative works from SimCast lesson content, narration, or educational materials
• Use automated tools to access or interact with the Service (except as explicitly permitted via documented APIs)
• Impersonate another person or entity, or falsely state or misrepresent your affiliation
• Attempt to gain unauthorized access to other users' accounts or data

8. Intellectual Property

The Service and its original content — including but not limited to SimCast lessons, narration audio, animation sequences, circuit templates, component designs, user interface, logos, and documentation — are and will remain the exclusive property of DigiSim Technology Ltd and its licensors. The Service is protected by copyright, trademark, and other intellectual property laws. Our trademarks and trade dress may not be used in connection with any product or service without our prior written consent. Purchasing content licenses does not transfer any intellectual property rights to you.

9. Software Errors, Simulation Limits, and What We Do Not Provide

No Guarantee of Perfection: The Service is a complex software system under continuous development. While we strive to provide a reliable, high-quality experience, we do not guarantee that the Service will be uninterrupted, error-free, secure, or free of bugs, defects, or vulnerabilities at all times.

Educational Simulator — Not for Safety-Critical Use: DigiSim is an educational digital logic simulator. It is not designed or licensed for use in safety-critical, life-critical, medical, aviation, automotive safety, nuclear, or industrial control systems. You must not rely on any simulation output, timing characteristic, or component model for decisions that could result in personal injury, property damage, or financial loss without independent hardware validation, professional engineering review, or other appropriate safeguards.

Simulation Accuracy: Circuit simulations are educational approximations built to illustrate fundamental digital logic principles in accordance with the platform's published component specifications. They are not a substitute for hardware validation, bench testing, SPICE-level analog accuracy, or professional engineering judgment. Simulations may not perfectly replicate real-world hardware behavior, timing, or analog effects. DigiSim does not guarantee the accuracy of simulation results for any purpose, including academic assessment or professional engineering.

Content May Contain Defects: We strive to implement every component, SimCast lesson, template, and example in strict accordance with established digital-logic principles. However, we do not guarantee that every simulation, lesson, or example is free from bugs, edge cases, or minor deviations from idealized behavior. We reserve the right to correct defects through updates, replacements, or (rarely) withdrawals, and such corrections are not grounds for refund beyond what is set out in the Refund Policy.

What We Do Not Provide: Unless specifically and separately purchased, DigiSim does not provide: (a) certification, accreditation, or recognition by any educational, industry, or professional body; (b) one-to-one tutoring, personalized learning plans, or human instruction; (c) guarantees that the Service will help you pass any exam, course, or qualification; (d) technical support, consulting, or custom development as part of educational content; (e) any warranty that the platform, content, or outputs are suitable for any particular purpose beyond the illustration of fundamental digital logic principles.

Data Integrity: We make reasonable efforts to protect your data and maintain backups. However, we are not liable for data loss, corruption, or inaccuracy caused by software bugs, system failures, third-party service outages, or events beyond our reasonable control. You are encouraged to export important work regularly.

Maintenance Windows: We may perform scheduled or emergency maintenance that temporarily interrupts the Service. We will make reasonable efforts to provide advance notice for planned maintenance.

Bug Reports: If you encounter a bug or error, we appreciate you reporting it to us. However, reporting a bug does not create an obligation on our part to fix it within any specific timeframe.

10. Termination and Suspension

By You: You may terminate your account at any time by using the account deletion feature or by contacting us. Upon deletion, your User Content and account data will be permanently removed after a reasonable grace period (typically 30 days).

By Us — For Cause: We may suspend or terminate your account immediately, without prior notice, if you breach these Terms, engage in prohibited activities, abuse resources, or engage in any conduct that we determine (at our sole discretion) is harmful to the Service, other users, or our business.

By Us — Without Cause: We may discontinue or substantially modify the Service at any time with 30 days' notice. In such case, we will make reasonable efforts to provide data export tools.

Effect of Termination: Upon termination, your right to access the Service ceases immediately. We are not obligated to maintain, return, or provide copies of your data after termination, except during any stated grace period.

No Refund for Violations: If your account is terminated due to a violation of these Terms, you are not entitled to any refund for purchased content.

Survival: All provisions of the Terms which by their nature should survive termination shall survive termination, including ownership provisions, warranty disclaimers, limitations of liability, and indemnity obligations.

11. Disclaimer of Warranties & Limitation of Liability

THE SERVICE IS PROVIDED ON AN "AS IS" AND "AS AVAILABLE" BASIS, WITHOUT WARRANTIES OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE. WE SPECIFICALLY DISCLAIM ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, AND ANY WARRANTIES ARISING FROM COURSE OF DEALING OR USAGE OF TRADE.

WE DO NOT WARRANT THAT (A) THE SERVICE WILL MEET YOUR REQUIREMENTS, (B) THE SERVICE WILL BE UNINTERRUPTED, TIMELY, SECURE, OR ERROR-FREE, (C) THE RESULTS OBTAINED FROM THE SERVICE WILL BE ACCURATE OR RELIABLE, OR (D) ANY DEFECTS IN THE SERVICE WILL BE CORRECTED.

IN NO EVENT SHALL DIGISIM TECHNOLOGY LTD, NOR ITS DIRECTORS, EMPLOYEES, PARTNERS, AGENTS, SUPPLIERS, OR AFFILIATES, BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, INCLUDING WITHOUT LIMITATION, LOSS OF PROFITS, DATA, USE, GOODWILL, OR OTHER INTANGIBLE LOSSES, RESULTING FROM (A) YOUR ACCESS TO OR USE OF OR INABILITY TO ACCESS OR USE THE SERVICE; (B) ANY CONDUCT OR CONTENT OF ANY THIRD PARTY ON THE SERVICE; (C) ANY CONTENT OBTAINED FROM THE SERVICE; OR (D) UNAUTHORIZED ACCESS, USE, OR ALTERATION OF YOUR CONTENT OR DATA.

OUR TOTAL AGGREGATE LIABILITY FOR ALL CLAIMS ARISING FROM OR RELATING TO THESE TERMS OR THE SERVICE SHALL NOT EXCEED THE GREATER OF (A) THE AMOUNT YOU HAVE PAID US IN THE TWELVE (12) MONTHS PRECEDING THE CLAIM, OR (B) ONE HUNDRED POUNDS STERLING (£100).

12. Indemnification

You agree to indemnify, defend, and hold harmless DigiSim Technology Ltd and its officers, directors, employees, agents, and affiliates from and against any and all claims, damages, losses, liabilities, costs, and expenses (including reasonable legal fees) arising from or related to: (a) your use of or access to the Service; (b) your violation of these Terms; (c) your violation of any third-party rights; or (d) your User Content.

13. Governing Law and Dispute Resolution

Governing Law: These Terms shall be governed by and construed in accordance with the laws of England and Wales, without regard to its conflict of law provisions.

Jurisdiction: Any disputes arising under these Terms shall be subject to the exclusive jurisdiction of the courts of England and Wales.

Consumer Rights: Nothing in these Terms shall limit any consumer protection rights you may have under your local law, including the UK Consumer Rights Act 2015 and the EU Consumer Rights Directive where applicable.

14. Changes to Terms

We reserve the right, at our sole discretion, to modify or replace these Terms at any time. If a revision is material, we will provide at least 30 days' notice prior to any new terms taking effect via email or a prominent notice within the Service. Continued use of the Service after changes take effect constitutes acceptance of the revised Terms. What constitutes a material change will be determined at our sole discretion.

15. Severability and Entire Agreement

If any provision of these Terms is held to be invalid or unenforceable, the remaining provisions shall remain in full force and effect. These Terms constitute the entire agreement between you and DigiSim Technology Ltd regarding the Service and supersede all prior agreements, understandings, and communications.

16. Contact Us

If you have any questions about these Terms, please contact us:

• Company: DigiSim Technology Ltd
• Address: Office 16555, 182-184 High Street North, East Ham, London, E6 2JA, United Kingdom
• By email: support@digisim.io
• Website: Contact Form