Last updated: February 28, 2026
These Terms of Service (“Terms”) are a legal agreement between you and Heavytail Labs, LLC, a Massachusetts limited liability company (“Heavytail Labs,” “we,” “us”). By creating an account or using Chalk at chalk.is (“the Service”), you agree to these Terms. If you do not agree, do not use the Service.
Chalk is a real-time sports analytics platform. It runs statistical and deep learning models against live game data to produce original analytical outputs including margin forecasts with calibrated confidence intervals, updated in real time during live games. Sports and leagues covered may change over time.
The Service includes:
Feature availability and usage limits vary by plan (Pro, Syndicate). Current plan details are available on our pricing page.
Chalk uses publicly available game data as inputs to its proprietary statistical and deep learning models. All predictions, confidence intervals, signals, and analytics produced by the Service are original analytical work generated by Chalk’s models — not reproductions of third-party content. Chalk is not affiliated with, endorsed by, or sponsored by any sports league, data provider, or athletic program. Team names are used solely for identification purposes.
Chalk uses Claude, an AI model by Anthropic, to generate halftime insights — brief contextual analyses of game state. These insights are generated automatically, cached, and shared across users. AI-generated content is informational, may contain errors, and should not be relied upon as the sole basis for any decision.
Chalk is an analytics tool, not a sportsbook or financial advisory service. It does not place bets, facilitate wagering, or process gambling transactions. All predictions, signals, and computational outputs are probabilistic estimates — not guaranteed outcomes. All content, predictions, and analytical outputs provided by the Service are for informational and educational purposes only.
Nothing in the Service constitutes betting advice, financial advice, or a recommendation to place any wager. Any sports wagering is inherently risky and undertaken at your own risk. Past model performance does not guarantee future results.
You are solely responsible for ensuring that your use of the Service complies with all applicable laws in your jurisdiction, including any laws governing sports wagering, betting advisory services, or gambling.
Chalk is currently in private beta. Access requires a valid invitation code. We may limit the number of users, restrict feature availability, or modify the Service during the beta period. Beta access does not guarantee continued availability.
You must be at least 18 years old to use the Service. By creating an account, you represent that you meet this requirement. If you access the Service from outside the United States, you do so at your own risk and are solely responsible for compliance with the laws of your jurisdiction, including any laws governing sports wagering, gambling analytics, or data services.
You need an account to use Chalk. You must provide a valid email address and verify it before your trial begins. You are responsible for keeping your login credentials secure and for all activity under your account. You must notify us promptly at support@chalk.is if you suspect unauthorized access. You are not liable for unauthorized activity that occurs after you notify us, provided you did not cause or facilitate the breach.
You may delete your account at any time from your account settings. Deletion cancels your Stripe subscription, removes your phone number if registered, and deactivates your account data. See our Privacy Policy for data retention details.
New accounts receive a 7-day free trial of their chosen plan (Pro at $149/month or Syndicate at $349/month). A valid credit card is required to start the trial. Your card is not charged during the trial period. If you do not cancel before the trial ends, your subscription automatically converts to a paid subscription. See our pricing page for details.
Paid subscriptions are billed through Stripe, either monthly or as a one-time season pass. Monthly subscriptions automatically renew each month unless you cancel. We do not store your credit card number — all payment processing is handled by Stripe, a PCI DSS-compliant payment processor (the industry security standard for handling card data).
Chalk is a seasonal product. Active seasons and their dates are listed on our pricing page. When a season ends, active monthly subscriptions are paused — you are not charged during the off-season. When the next season begins, your subscription automatically resumes and billing restarts. You may cancel at any time during the off-season to prevent automatic resumption. No action is required on your part to stop off-season charges.
You may cancel your subscription at any time from your account settings. Cancellation takes effect at the end of your current billing period — you retain access until then. No partial refunds are issued for monthly subscriptions or season passes.
We will give at least 30 days’ notice before changing subscription prices. Price changes apply to subsequent billing periods, not your current period.
Syndicate subscribers receive API access to Chalk’s data and predictions, subject to the following limits:
API access is for your personal use or your organization’s internal use. You are responsible for keeping your API credentials secure. You may not redistribute, resell, or sublicense API data. We may suspend API access if you exceed rate limits or violate these Terms. No uptime guarantee is provided for API availability. API access is tied to your subscription — it ends when your subscription ends.
Pro and Syndicate subscribers may opt in to receive SMS alerts for halftime analytics alerts and account notifications. SMS alerts are delivered by Twilio. For the full SMS messaging policy, see our SMS Terms.
You agree not to:
We may suspend or terminate accounts that violate these rules.
The Service — including its proprietary statistical models, algorithms, analytical outputs, user interface, and generated content — is owned by Heavytail Labs, LLC and protected by applicable intellectual property laws. All predictions, signals, and analytics produced by the Service constitute original works of Heavytail Labs. Your subscription grants you a personal, non-transferable, non-exclusive license to use the Service. You may not copy, modify, or create derivative works from the Service.
We do not warrant that:
All outputs of the Service — predictions, signals, probabilities, and computational tools — are probabilistic estimates based on statistical models. They are not guarantees of any outcome and should not be the sole basis for financial decisions.
Our total liability for any claim arising from your use of the Service is limited to the amount you paid us in the 12 months before the claim arose.
You agree to indemnify and hold harmless Heavytail Labs, LLC and its officers, employees, and agents from any claims, damages, losses, or expenses (including reasonable attorneys’ fees) arising from your use of the Service, your violation of these Terms, or any decisions you make based on the Service’s outputs.
We may change or discontinue any part of the Service at any time. We will make reasonable efforts to notify users of material changes but are not liable for any modification or discontinuation.
We may update these Terms. We will notify you of material changes by email or in-app notification at least 15 days before they take effect. Continued use of the Service after changes take effect constitutes acceptance of the updated Terms.
These Terms are governed by the laws of the Commonwealth of Massachusetts. Any disputes shall be resolved in the state or federal courts located in Massachusetts, and you consent to the jurisdiction of those courts.
Questions about these Terms: legal@chalk.is