Fantasy decisions, explained
How to connect a Sleeper NFL league
Read-only league import: what it loads, how to connect and where experimental trade recommendations stop.
Implemented in this preview: NFL rosters, scoring and recorded standings. No password or API token required. No trade submission.
Connect in four steps
- Open League HQ and choose Sleeper.
- Enter your Sleeper username or a league ID, then choose Find leagues.
- Choose the league and your roster. Inspect every available team, its record and scoring settings.
- Refresh manually when you want new data. Reloading the page clears the imported state.
Try experimental trade recommendations
Upload a JSON array with Sleeper player IDs and weekly projected points matching your scoring:
[{"player_id":"1234","points":15.2}]The ID above is only a format example. Supply real IDs and complete coverage for the evaluated rosters. The file must be under 2 MB and contain unique IDs with finite, nonnegative point values. The finder evaluates one-for-one swaps and shows up to three that improve both optimized starting lineups by more than 0.1 projected points.
What it cannot do
- Submit, accept or monitor trades automatically.
- Supply a validated projection feed, forecast season records or price future picks.
- Import Sleeper FC or other providers through this NFL connector.
- Guarantee availability when the upstream API is unavailable.
Troubleshooting
If a username returns no current-season leagues, check its spelling or try the specific league ID. If recommendations cannot be calculated, check player-ID coverage, scoring consistency and supported lineup slots. More than 18 starters, unsupported slots or an impossible full lineup cannot be evaluated.
Source and access terms
Sleeper’s API documentation describes its read-only endpoints and says commercial use requires contacting Sleeper about licensing. A working public endpoint does not establish commercial permission. The implementation has been reviewed; this guide is not a claim that every league has been tested.
Full optimizer and grade methodology · How inputs are handled