API Documentation

Getting started

The Stats Guy Fantasy API serves player and pick values derived from real dynasty and redraft trades across thousands of Sleeper leagues. Values are recalculated on a regular run cadence (roughly daily), and historical snapshots are archived per run. See our methodology for how values are computed.

All endpoints are served over HTTPS from a single base URL. There is no authentication and no API key. If other people see the data in your product, include a visible credit such as “Data from Stats Guy Fantasy”, linked to statsguyfantasy.com; see the terms of service.

https://api.statsguyfantasy.com/api/v1

Fetch the top of the superflex dynasty board:

curl "https://api.statsguyfantasy.com/api/v1/rankings?format=sf_dynasty&limit=5"

The API root (GET https://api.statsguyfantasy.com/api/v1) is a discovery endpoint that lists every endpoint and its parameters as JSON. CORS is open, so you can call the API directly from browser apps.

Optional: set a descriptive User-Agent, such as MyApp/1.0 (+https://myapp.com), to identify your integration and help us contact you about API changes.

This reference is also available as a single plain-markdown file at /developers/docs.md for use with AI coding agents and LLM tools; a site index for LLMs lives at /llms.txt.

Rate limits & caching

Requests are rate limited per IP address, currently 60 requests per minute. Every response carries X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset (unix seconds) headers. When you exceed the limit you get a 429 response with a Retry-After header. Back off until then.

Responses are gzip-compressed and may be served from a cache for up to an hour, so don't depend on sub-hour freshness. Because values only change when a calculation run completes (roughly daily), polling faster than that gains nothing anyway. For bulk consumers, one GET /players sync per day is plenty. If you need more headroom than the per-IP limit, email contact@statsguyfantasy.com.

League formats

Values are calculated independently for four league formats:

List endpoints are format-scoped: ?format= (or the format body field) picks the lens. Entity endpoints are format-complete: player detail and picks return value (and related fields) as per-format maps, so one call covers every league type.

Values cover offensive players (QB, RB, WR, TE) and draft picks. Defenders (DL, LB, DB) are added for IDP leagues with the idp parameter (IDP leagues); without it a defender's ID resolves as not found.

TE premium

TE values default to a blend of standard and TE-premium (TEP) leagues. To price TEs for one kind of league, pass the tep parameter to GET /rankings, GET /players, GET /players/:id, GET /players/:id/value-history, and the trade evaluate endpoints:

Only TE values change, and ranks are recomputed from the adjusted values. Every response includes tep, the tier it was priced at.

IDP leagues

IDP values are dynasty only and sit on the same scale as offense. To price a league that starts defenders, pass idp with the league's roster-depth tier to GET /rankings, GET /players, GET /players/:id, GET /players/:id/value-history, and the trade evaluate endpoints. Without it, responses are for a league without IDP.

The scoring ratio is the points a sack earns, counting the solo tackle, tackle for loss, and QB hit it also scores, plus the points for an interception and a pass defended, divided by the points for a solo tackle. In Sleeper's scoring keys: (idp_tkl_solo + idp_sack + idp_tkl_loss + idp_qb_hit + idp_int + idp_pass_def) / idp_tkl_solo, with idp_tkl added to both solo terms. A league that scores no solo tackles is bigplay if it scores any of the others. idpScoring requires idp.

With idp, a defender's value appears under both sf_dynasty and non_sf_dynasty (IDP values don't depend on the QB format) and he has no redraft values; combining idp with a redraft format returns 400. Rankings put offense and defenders on one board with one contiguous rank, so offense ranks shift once defenders are included. A player eligible on both sides of the ball (Travis Hunter, WR/DB) is a DB in an IDP league, priced from IDP-league trades; dates before he had an IDP value leave him out. Responses echo idp and idpScoring, and current-value responses add idpAsOf, the timestamp of the IDP value run.

Player & pick IDs

Player IDs are Sleeper player IDs, returned by every endpoint as id and accepted anywhere a player ID is expected (path parameters, trade-evaluate sides) — pass IDs straight from Sleeper rosters and transactions. Every player also carries url, its player page on statsguyfantasy.com (null if the player isn't in our database).

curl "https://api.statsguyfantasy.com/api/v1/players/7564"

Rookie draft picks use structured IDs in three forms:

Player metadata (names, teams, positions, ages) is synced from the Sleeper API; position eligibility (fantasyPositions) follows Sleeper's classification. Values and rankings are Stats Guy Fantasy's own trade-derived data.

Dates & history

Dates are always strict YYYY-MM-DD; other spellings are rejected with 400. Historical lookups resolve to the latest snapshot on or before the requested date, looking back at most 14 days; the snapshot date actually used is echoed back as asOf. Daily snapshots go back to 2022-08-01 for all formats; rankings requests with no snapshot in range return an empty board with an earliestAvailable hint. IDP history starts on the same date but is thinner in its first season: about 170 defenders were valued in August 2022, against roughly 230 from 2023 on, and their values moved more from day to day.

The asOf / valuesAsOf fields on current-value responses are the timestamp of the value-calculation run that produced the data (per format), not the request time. Formats update independently: dynasty values recompute year-round, while redraft values only recompute during the fantasy season and freeze at their last computed level through the offseason — so a redraft asOf can trail dynasty by months. That gap is deliberate (there is no meaningful redraft trade market in the offseason), not a data outage.

Errors

Errors are JSON with the shape { "error": "...", "message": "..." }:

curl "https://api.statsguyfantasy.com/api/v1/rankings?format=sf_dynasty&position=WR&limit=1"

{
  "format": "sf_dynasty",
  "tep": "blend",
  "asOf": "2026-08-04T13:01:35.221Z",
  "total": 147,
  "limit": 1,
  "offset": 0,
  "rankings": [
    {
      "rank": 3,
      "id": "7564",
      "name": "Ja'Marr Chase",
      "url": "https://statsguyfantasy.com/player/jamarr-chase-7usy7y",
      "team": "CIN",
      "position": "WR",
      "positionRank": 1,
      "value": 9466,
      "age": 26.4,
      "yearsExperience": 5
    }
  ]
}

{
  "total": 397,
  "tep": "blend",
  "valuesAsOf": {
    "sf_dynasty": "2026-08-04T13:01:35.221Z",
    "non_sf_dynasty": "2026-08-04T13:01:35.221Z",
    "sf_redraft": "2026-08-04T13:01:35.221Z",
    "non_sf_redraft": "2026-08-04T13:01:35.221Z"
  },
  "players": [
    {
      "id": "9509",
      "name": "Bijan Robinson",
      "url": "https://statsguyfantasy.com/player/bijan-robinson-6v82sl",
      "team": "ATL",
      "position": "RB",
      "value": {
        "sf_dynasty": 10000,
        "non_sf_dynasty": 10000,
        "sf_redraft": 7458,
        "non_sf_redraft": 9823
      }
    }
  ]
}

curl "https://api.statsguyfantasy.com/api/v1/players/7564"

{
  "id": "7564",
  "name": "Ja'Marr Chase",
  "url": "https://statsguyfantasy.com/player/jamarr-chase-7usy7y",
  "team": "CIN",
  "position": "WR",
  "fantasyPositions": ["WR"],
  "age": 26.4,
  "yearsExperience": 5,
  "rookieYear": 2021,
  "dataUpdatedAt": "2026-08-04T18:00:02.821Z",
  "value": {
    "sf_dynasty": 9466,
    "non_sf_dynasty": 9117,
    "sf_redraft": 9794,
    "non_sf_redraft": 8680
  },
  "rank": {
    "sf_dynasty": 3,
    "non_sf_dynasty": 3,
    "sf_redraft": 2,
    "non_sf_redraft": 3
  },
  "positionRank": {
    "sf_dynasty": 1,
    "non_sf_dynasty": 1,
    "sf_redraft": 1,
    "non_sf_redraft": 1
  },
  "valueChange": {
    "sf_dynasty": { "days7": -148, "days30": -80 },
    "non_sf_dynasty": { "days7": -17, "days30": -626 },
    "sf_redraft": { "days7": 543, "days30": 543 },
    "non_sf_redraft": { "days7": 35, "days30": 35 }
  },
  "tep": "blend",
  "valuesAsOf": {
    "sf_dynasty": "2026-08-04T13:01:35.221Z",
    "non_sf_dynasty": "2026-08-04T13:01:35.221Z",
    "sf_redraft": "2026-08-04T13:01:35.221Z",
    "non_sf_redraft": "2026-08-04T13:01:35.221Z"
  }
}

curl "https://api.statsguyfantasy.com/api/v1/players/7564/value-history?format=sf_dynasty&window=2"

{
  "id": "7564",
  "name": "Ja'Marr Chase",
  "url": "https://statsguyfantasy.com/player/jamarr-chase-7usy7y",
  "format": "sf_dynasty",
  "tep": "blend",
  "history": [
    { "date": "2026-08-04", "value": 9466 },
    { "date": "2026-08-03", "value": 9545 }
  ]
}

{
  "total": 120,
  "valuesAsOf": {
    "sf_dynasty": "2026-08-04T13:01:35.221Z",
    "non_sf_dynasty": "2026-08-04T13:01:35.221Z",
    "sf_redraft": "2026-08-04T13:01:35.221Z",
    "non_sf_redraft": "2026-08-04T13:01:35.221Z"
  },
  "picks": [
    {
      "id": "pick:2026:2.08",
      "year": 2026,
      "round": 2,
      "slot": 8,
      "value": {
        "sf_dynasty": 246,
        "non_sf_dynasty": 316
      }
    },
    {
      "id": "pick:2027:1:early",
      "year": 2027,
      "round": 1,
      "variant": "early",
      "value": {
        "sf_dynasty": 3762,
        "non_sf_dynasty": 3658
      }
    }
  ]
}

curl -X POST "https://api.statsguyfantasy.com/api/v1/trades/evaluate" \
  -H "Content-Type: application/json" \
  -d '{
    "format": "sf_dynasty",
    "sideA": ["7564", "pick:2027:1:early"],
    "sideB": ["4984", "pick:2026:2.08"]
  }'

{
  "format": "sf_dynasty",
  "tep": "blend",
  "asOf": "2026-08-04T13:01:35.221Z",
  "sideA": {
    "assets": [
      {
        "id": "7564",
        "type": "player",
        "name": "Ja'Marr Chase",
        "url": "https://statsguyfantasy.com/player/jamarr-chase-7usy7y",
        "position": "WR",
        "team": "CIN",
        "value": 9466,
        "found": true
      },
      {
        "id": "pick:2027:1:early",
        "type": "pick",
        "name": "2027 Round 1 (early)",
        "value": 3762,
        "found": true
      }
    ],
    "totalValue": 13228
  },
  "sideB": {
    "assets": [
      {
        "id": "4984",
        "type": "player",
        "name": "Josh Allen",
        "url": "https://statsguyfantasy.com/player/josh-allen-ntn4px",
        "position": "QB",
        "team": "BUF",
        "value": 9246,
        "found": true
      },
      {
        "id": "pick:2026:2.08",
        "type": "pick",
        "name": "2026 Pick 2.08",
        "value": 246,
        "found": true
      }
    ],
    "totalValue": 9492
  },
  "differential": 3736
}

curl -X POST "https://api.statsguyfantasy.com/api/v1/trades/evaluate/batch" \
  -H "Content-Type: application/json" \
  -d '{
    "trades": [
      {
        "format": "sf_dynasty",
        "date": "2026-03-01",
        "sideA": ["7564"],
        "sideB": ["4984", "pick:2027:1"]
      },
      {
        "format": "non_sf_dynasty",
        "sideA": ["pick:2026:1.04"],
        "sideB": ["9509"]
      }
    ]
  }'

{
  "total": 2,
  "results": [
    {
      "format": "sf_dynasty",
      "tep": "blend",
      "date": "2026-03-01",
      "sideA": { "assets": [ ... ], "totalValue": 9479 },
      "sideB": { "assets": [ ... ], "totalValue": 12052 },
      "differential": -2573
    },
    {
      "format": "non_sf_dynasty",
      "tep": "blend",
      "asOf": "2026-08-04T13:01:35.221Z",
      "sideA": { "assets": [ ... ], "totalValue": 2501 },
      "sideB": { "assets": [ ... ], "totalValue": 10000 },
      "differential": -7499
    }
  ]
}

{
  "days": 30,
  "mostTraded": {
    "dynasty_sf": [
      {
        "id": "11631",
        "name": "Brian Thomas",
        "url": "https://statsguyfantasy.com/player/brian-thomas-h7h68x",
        "team": "JAX",
        "position": "WR",
        "tradeCount": 604
      }
    ],
    "dynasty_non_sf": [ ... ],
    "redraft_sf": [ ... ],
    "redraft_non_sf": [ ... ]
  }
}

MCP server

The same values are available through a Model Context Protocol server, so ChatGPT, Claude, and other MCP hosts can look up players and evaluate trades by name. Add it as a remote MCP server or connector:

https://api.statsguyfantasy.com/mcp

Streamable HTTP transport, no authentication. Every tool is read-only and wraps the REST endpoints above. Players and picks can be given by name ("Bijan Robinson", "early 2027 1st", "2026 1.03") or by ID. Coverage matches the REST API: the same tep tiers, and defenders when a tool call passes idp (defender names only match then).

MCP requests are limited to 150 per minute per IP, separately from the REST API. For bulk data, use the REST API.