No Sleeper credentialsOnly a public username is needed.
Your league data stays public, read-only, and temporary.
FourthDahn is a prototype that organizes information already available through Sleeper's public API. It does not ask for your Sleeper password, modify your league, or maintain a persistent database of Sleeper users, leagues, rosters, or transactions.
Effective August 16, 2026No persistent league databasePublic league data is processed on demand.
Transparent AI-assisted analysisPublic league and NFL data may be processed by AI models to generate requested insights.
1. Scope
This policy explains how the FourthDahn prototype handles information when you use the application. It applies to the prototype interface, its API, and the features that display public Sleeper fantasy-football information.
2. Information the application accesses
When you enter a Sleeper username, the application requests public information made available by Sleeper. Depending on the selected league, this can include:
- Public usernames, display names, avatars, and team images
- League names, settings, seasons, and roster configurations
- Rosters, players, taxi squads, and injured-reserve lists
- Standings, scores, records, and playoff brackets
- Drafts, draft picks, pick ownership, and draft history
- Public transaction and trade history
- NFL player, team, game, scoring, projection, ranking, and other fantasy-relevant statistical data from identified data sources
The application does not request or receive your Sleeper password, private messages, payment information, or permission to make changes to your Sleeper account.
3. How information and AI are used
Public Sleeper information is used only to generate the views and analysis you request—for example, roster pages, live standings, league history, trade comparisons, and draft-pick lineage. The integration is read-only and cannot add, drop, trade, draft, or move players on your behalf.
FourthDahn also uses, and plans to expand its use of, artificial intelligence and machine-learning models to process public league information together with NFL statistical data. These systems may identify patterns and produce roster-decision support, player and team comparisons, trade insights or grades, draft analysis, projections, explanations, and other fantasy-football guidance.
When an AI-assisted feature is used, the information needed for the requested analysis may be supplied as input to a model operated by FourthDahn or a model-service provider. FourthDahn does not use Sleeper passwords or private messages for these features. Public league data is not used to train a FourthDahn model unless this policy is updated and users are given notice before that practice begins.
AI and machine-learning outputs are probabilistic and may be incomplete, outdated, or incorrect. They are provided as informational decision support; users remain responsible for roster, lineup, waiver, draft, and trade decisions.
4. Data collection summary
This plain-language summary describes the current web prototype. It is designed to support, but does not replace, the separate App Store Connect and Google Play Console disclosures required if a native mobile application is released. Those store disclosures will be reviewed against the exact mobile build and its third-party SDKs before submission.
Data typeUse and handling
Public account identifiersA Sleeper username, user ID, display name, avatar, and public team identity are used for app functionality and requested analysis. They are not used for advertising or cross-app tracking.
Public league and gameplay contentRosters, transactions, drafts, scores, standings, and league settings are processed to display league features and generate requested statistical or AI-assisted insights. FourthDahn does not maintain a persistent league database.
NFL statistical dataPlayer, team, game, scoring, projection, and ranking data may be combined with public league data for app functionality, analytics requested by the user, and AI-assisted decision support.
Operational and diagnostic dataHosting providers may temporarily process IP addresses, request timestamps, URLs, response codes, browser details, performance data, and crash information for security, reliability, and troubleshooting.
Tracking, advertising, and saleThe current prototype does not use data for cross-app tracking, targeted advertising, or sale to data brokers.
5. Storage and retention
FourthDahn does not maintain a persistent application database containing Sleeper usernames, league data, roster data, or transaction history. Public API responses may be held temporarily in server memory to improve performance and reduce repeated calls to Sleeper. These temporary caches expire and are cleared when the application process restarts.
Your light or dark appearance preference is stored locally in your own browser using local storage. It does not contain Sleeper data and is not transmitted as an account profile. You can remove it by clearing this site's browser data.
6. Cookies, analytics, and advertising
The prototype does not use advertising cookies, behavioral tracking, or targeted advertising, and it does not sell personal information. The application currently does not create user accounts or authentication cookies.
7. Infrastructure and operational logs
Like most internet services, the hosting or networking provider may create limited operational logs such as request timestamps, IP addresses, requested URLs, response codes, and browser information for security, reliability, and troubleshooting. FourthDahn does not combine these logs with Sleeper league data to build user profiles. Provider handling of infrastructure logs is governed by the applicable provider's own privacy terms.
8. Third-party services
Sleeper supplies the public fantasy-football data displayed by the application. Player and team images may also be delivered from Sleeper-controlled content services. Sleeper's collection and use of information is governed by Sleeper's own policies. FourthDahn is an independent prototype and is not operated by or endorsed by Sleeper.
NFL statistics, projections, rankings, or related context may come from public or licensed third-party datasets identified in the applicable feature. AI-assisted features may also rely on external model-service providers. Those providers process the limited data sent to them under their applicable terms, privacy policies, and the service configuration selected by FourthDahn.
9. Data sharing
FourthDahn does not sell, rent, or license Sleeper data. Public data is sent only where necessary to operate the requested feature, such as between the browser, this application's API, Sleeper's public API, NFL statistical-data sources, infrastructure providers, and AI model providers used to generate an analysis that the user requests.
10. Security and limitations
Reasonable technical measures are used to keep the prototype read-only and limit unnecessary data handling. No internet service can guarantee absolute security. Because Sleeper league information accessed here is publicly available, users should avoid putting sensitive personal information in public team names, avatars, or other Sleeper profile fields.
11. Your choices
You can stop using the application at any time. Because the prototype does not maintain persistent Sleeper profiles, there is no stored league account to delete from FourthDahn. You can clear the local appearance preference through your browser's site data controls.
12. Policy changes and questions
This policy may be updated as the prototype gains features such as accounts, saved preferences, analytics, or assistant functionality. Material changes to data handling should be reflected here before those features are made available. For questions, contact the league administrator or prototype owner who provided access to this application.