UnerringAPI

Authentication

Send your key in a header, either form. Keys start with ua_live_.

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/usage" \
  -H "Authorization: Bearer ua_live_..."

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/usage" \
  -H "X-API-Key: ua_live_..."

A key in the URL is refused with 400 api_key_in_url, whether as api_key, apikey or key, because URLs end up in logs. The secret is shown once when the key is issued and is stored only as a keyed hash, so a lost key has to be rotated.

The API is read-only. Only GET and HEAD are accepted; any other method gets 404 endpoint_not_found. A HEAD request is charged like a GET.

What a key can be limited to

The order of checks

Method, then key (present, valid, not revoked, not expired, account active, address allowed), then rate limit, then the path, then the scope, then the plan's features and the parameters, then the credit charge. A request refused at any step costs no credits from your balance.

Responses

Every success is { data, meta }. Every failure is { error, meta }.

{
  "data": [],
  "meta": {
    "request_id": "req_7f3a9c21d4e84b60a1c2",
    "count": 0,
    "credits_used": 1,
    "credits_remaining": 149811,
    "generated_at": "2026-11-06T18:00:00.000Z",
    "total": 0,
    "has_more": false
  }
}

Some endpoints add their own fields to meta; those are noted under each one. Responses are Cache-Control: private, no-store and vary on the key headers, so a CDN can't replay one caller's answer to another.

Credits

The cost is fixed per request, whatever the size of the answer. Errors are never charged.

Plans

• Edge's allowance runs for 30 days from the account's first request after the plan was set, not by calendar month, and does not roll over.
• Sandbox's 50 credits are a single grant and do not refill.
• Credits the operator adds on top are kept when an allowance resets, but changing an account's plan clears the whole balance.
• On an unlimited plan credits_remaining is null and your balance doesn't move. A key's monthly cap still counts.
• The webhooks feature is in the plan definitions, but no webhook endpoint exists yet.

Rate limits and headers

The limit is per account, and all of an account's keys share it. Each request counts, including free endpoints. The window is fixed: it starts with your first request and lasts 60 seconds. Over the limit you get 429 rate_limited with a Retry-After header, and no charge.

Errors

{
  "error": {
    "code": "invalid_parameter",
    "message": "limit must be a number between 1 and 200",
    "param": "limit"
  },
  "meta": { "request_id": "req_a81c4e07b39f42d6b0e5" }
}

code is stable, so branch on it. message is for people. param names the parameter at fault and is an empty string when none is.

A plain HTTP request to /v1/stream gets status 426 with the code invalid_parameter, because that path only takes WebSocket connections.

Paging

A paged answer always says whether there is more, so a short answer is never mistaken for a complete one. A limit above the maximum is refused rather than quietly lowered.

BASE="https://unerring-api.liam-banks2004.workers.dev"
cursor=""
while :; do
  page=$(curl -s "$BASE/v1/events?league=nba&limit=100${cursor:+&cursor=$cursor}" \
    -H "Authorization: Bearer $UNERRING_KEY")
  echo "$page" | jq -c '.data[]'
  cursor=$(echo "$page" | jq -r '.meta.next_cursor // empty')
  [ -z "$cursor" ] && break
done

Pass cursors unchanged, with the same filters. They bind pages to a revision and as_of time; an expired cursor or changed revision returns 409 cursor_expired. Restart from the first page when that happens. Paging stored records does not establish complete upstream venue coverage.

Everything else returns its full list and has no paging fields, including /v1/scores, /v1/teams and /v1/players.

Common parameters

These mean the same wherever they appear, except where an endpoint says otherwise: on /v1/best-lines, include_stale only lets stale prices compete. Lists are comma-separated and case doesn't matter, except for the exact native filters on /v1/prediction-contracts. That endpoint also refuses unsupported or repeated parameters.

Periods

A period is what the source said it was. It is never assumed, so a part-game line always says so. /v1/leagues lists the periods on the board for each league right now, and /v1/markets returns this full list in meta.periods.

Market keys

This is the catalog from /v1/markets. A key being listed doesn't mean any book is pricing it now: /v1/leagues shows the keys on the board for each league.

Shortcuts in the markets parameter: main is moneyline, spread and total. props and player_* are every key starting player_. all is every key, including three_way and the alternates, which main doesn't include.

An outcome's side is one of home, away, draw, over, under. Its point is the side's own handicap on a spread and the line on a total or prop.

A team_total market's player is the team it is about, named as that book writes it. When the board can place the team on a side of the game from that book's own home and away names, player.side is home or away, and player.id and every selection id in the market are keyed by that side of the game rather than by the spelling. So "NY Islanders" at one book and "New York Islanders" at another, for the same period and line, have the same selection ids. When the board can't place the team for certain (a name that fits neither side or both, or a listing the board matched the other way round), player.side is left out and the ids stay keyed by the book's spelling. Market ids are per book and didn't change.

Team-total selection ids and player.id changed once, when side keying was released in November 2026. An id saved for a team total before then isn't found afterwards. In the stream, each team total that moved to a side was sent once, as its book was next read, with the same prices and its new selection ids.

Leagues

A league id being accepted doesn't mean it has events. /v1/leagues gives the current count for each.

Ids

Treat ids as opaque strings. None of them contains a comma, so they are safe in list parameters.

Account and catalog

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/status" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "status": "ok",
  "time": "2026-11-06T18:00:00.000Z",
  "provider": "UnerringAPI",
  "account": { "plan": "edge", "credits": 149812 },
  "feed": {
    "events": 412,
    "live": 9,
    "markets": 18640,
    "updates_total": 902211,
    "updates_per_minute": 6,
    "uptime_seconds": 86400
  },
  "sources": [
    { "id": "prophetx", "name": "ProphetX", "type": "direct", "status": "operational", "last_ok": "2026-11-06T17:59:40.000Z" }
  ]
}

{
  "plan": "edge",
  "plan_name": "Edge",
  "credits_remaining": 149812,
  "unlimited": false,
  "monthly_credits": 150000,
  "credits_reset_at": "2026-12-06T18:00:00.000Z",
  "rate_limit_per_minute": 300,
  "max_stream_connections": 0,
  "features": ["rest", "props", "futures", "history", "ev", "dfs"],
  "requests_24h": 94,
  "credits_used_24h": 188,
  "requests_30d": 94,
  "credits_used_30d": 188,
  "key": { "id": "key_4c1f0a9e7b2d45c8a1e3", "name": "Default key", "env": "live" }
}

{
  "id": "nba",
  "name": "NBA",
  "full_name": "nba",
  "sport": "basketball",
  "region": "global",
  "periods": ["full_game", "1h"],
  "has_player_props": true,
  "has_futures": false,
  "markets": ["moneyline", "spread", "total", "player_points"],
  "events": { "upcoming": 11, "live": 0 }
}

{
  "data": [
    { "key": "moneyline", "name": "Moneyline", "group": "main", "description": "Moneyline" }
  ],
  "meta": {
    "request_id": "req_11b2c3d4e5f6a7b8c9d0",
    "count": 21,
    "credits_used": 0,
    "credits_remaining": 149812,
    "generated_at": "2026-11-06T18:00:00.000Z",
    "periods": ["full_game", "1h", "2h"],
    "shortcuts": { "main": ["moneyline", "spread", "total"], "props": "player_*", "all": "*" }
  }
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/sportsbooks?type=exchange" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "id": "prophetx",
  "name": "ProphetX",
  "type": "exchange",
  "tags": ["sharp_reference", "us"],
  "status": "operational",
  "leagues": ["nba", "nhl"],
  "ev_role": "reference",
  "ev_weight": 50,
  "scoring_eligible": true,
  "effective_scoring_eligible": true,
  "effective_scoring_state": "eligible",
  "effective_ev_role": "reference",
  "effective_ev_weight": 50,
  "effective_scoring_reason": null,
  "last_seen": "2026-11-06T17:59:40.000Z"
}

{ "id": "nba_celtics", "league": "nba", "name": "Boston Celtics", "abbr": "BC" }

{ "id": "plr_0c9x3m1q7a5tkd", "name": "J. Example", "position": "F", "team_id": null, "team": "Boston Celtics", "league": "nba" }

Events and odds

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/events?league=nba,nhl&limit=50" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "id": "evt_0h7k2m9q4x1tzb",
  "league": "nba",
  "sport": "basketball",
  "competition": "",
  "start_time": "2026-11-07T00:30:00.000Z",
  "start_time_tbc": false,
  "start_time_spread_minutes": 0,
  "start_time_outliers": [],
  "status": "scheduled",
  "status_observed_at": null,
  "status_stale": false,
  "home": { "id": "nba_celtics", "name": "Boston Celtics", "abbr": "BC" },
  "away": { "id": "nba_knicks", "name": "New York Knicks", "abbr": "NYK" },
  "score": null,
  "clock": null
}

{
  "sources": ["prophetx"],
  "markets": ["moneyline", "spread", "total"]
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/odds?league=nba&markets=spread,total&format=decimal" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "data": [
    {
      "id": "evt_0h7k2m9q4x1tzb",
      "league": "nba",
      "sport": "basketball",
      "competition": "",
      "start_time": "2026-11-07T00:30:00.000Z",
      "start_time_tbc": false,
      "start_time_spread_minutes": 0,
      "start_time_outliers": [],
      "status": "scheduled",
      "status_observed_at": null,
      "status_stale": false,
      "home": { "id": "nba_celtics", "name": "Boston Celtics", "abbr": "BC" },
      "away": { "id": "nba_knicks", "name": "New York Knicks", "abbr": "NYK" },
      "score": null,
      "clock": null,
      "bookmakers": [
        {
          "id": "prophetx",
          "name": "ProphetX",
          "type": "exchange",
          "updated_at": "2026-11-06T17:59:40.000Z",
          "time_basis": "read",
          "markets": [
            {
              "id": "mkt_0k2v9qa1x7m3pc",
              "key": "total",
              "period": "full_game",
              "line": 224.5,
              "outcomes": [
                { "id": "sel_1f8s2ld0q9w4ze", "name": "Over", "side": "over", "point": 224.5, "price": 1.9259, "liquidity": 840 },
                { "id": "sel_0p3n7ty5h2c6vb", "name": "Under", "side": "under", "point": 224.5, "price": 1.8929, "liquidity": 1120 }
              ],
              "suspended": false
            }
          ]
        }
      ]
    }
  ],
  "meta": {
    "request_id": "req_2c7e1d0a9b8f4c3e6a51",
    "count": 1,
    "credits_used": 2,
    "credits_remaining": 149810,
    "generated_at": "2026-11-06T18:00:00.000Z",
    "total": 1,
    "has_more": false,
    "markets": ["spread", "total"],
    "periods": ["full_game"],
    "format": "decimal"
  }
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/events/evt_0h7k2m9q4x1tzb/odds?markets=all" \
  -H "Authorization: Bearer $UNERRING_KEY"

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/props?league=nba&markets=player_points&player=example" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "id": "dabble",
  "name": "Dabble",
  "type": "dfs",
  "updated_at": "2026-11-06T17:58:10.000Z",
  "time_basis": "read",
  "markets": [
    {
      "id": "mkt_1r8d0s4n6y2gha",
      "key": "player_points",
      "period": "full_game",
      "line": 27.5,
      "player": { "id": "plr_0c9x3m1q7a5tkd", "name": "J. Example", "team": "Boston Celtics", "position": "F" },
      "variant": "standard",
      "outcomes": [
        { "id": "sel_2m5w9e3r7t1yuj", "name": "Over", "side": "over", "point": 27.5, "price": null },
        { "id": "sel_1q6k4z8x2c0vbn", "name": "Under", "side": "under", "point": 27.5, "price": null }
      ],
      "suspended": false
    }
  ]
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/prediction-contracts?source=polymarket_us&kind=contract,bbo&limit=100" \
  -H "Authorization: Bearer $UNERRING_KEY"

curl -sN "https://unerring-api.liam-banks2004.workers.dev/v1/prediction-contracts?source=polymarket_us&export=ndjson" \
  -H "Authorization: Bearer $UNERRING_KEY"

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/best-lines?league=nhl&markets=moneyline" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "markets": [
    {
      "key": "moneyline",
      "period": "full_game",
      "books_quoting": 3,
      "outcomes": [
        { "id": "sel_3a1s5d9f2g6hjk", "name": "Home", "side": "home", "best_price": -118, "best_books": ["bovada"] },
        { "id": "sel_0z4x8c2v6b1nml", "name": "Away", "side": "away", "best_price": 112, "best_books": ["prophetx", "smarkets"] }
      ]
    }
  ]
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/history?event_id=evt_0h7k2m9q4x1tzb&book=prophetx&market=total" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "market_id": "mkt_0k2v9qa1x7m3pc",
  "open": {
    "t": "2026-11-06T12:00:00.000Z",
    "line": 224.5,
    "prices": [
      { "side": "over", "point": 224.5, "price": -110 },
      { "side": "under", "point": 224.5, "price": -110 }
    ]
  },
  "current": {
    "t": "2026-11-06T17:59:40.000Z",
    "line": 224.5,
    "prices": [
      { "side": "over", "point": 224.5, "price": -108 },
      { "side": "under", "point": 224.5, "price": -112 }
    ]
  },
  "points": []
}

Computed

These come from the current board after the gates. The method is under How EV is worked out.

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/ev?league=nba&min_ev=2&limit=50" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "book": "draftkings",
  "book_name": "DraftKings",
  "event_id": "evt_0h7k2m9q4x1tzb",
  "league": "nba",
  "market": "total",
  "period": "full_game",
  "line": 224.5,
  "side": "over",
  "player_id": null,
  "price": -105,
  "decimal": 1.9524,
  "fair_probability": 0.5312,
  "fair_price": -113,
  "fair_decimal": 1.8825,
  "ev_percent": 3.71,
  "ev_worst_case_percent": 3.12,
  "edge_points": 1.9,
  "kelly_fraction": 0.039,
  "references": ["pinnacle", "prophetx"],
  "reference_families": 2,
  "devig_method": "shin",
  "plausible": true,
  "stale": false,
  "stale_reason": null,
  "conditional_on_no_push": false,
  "liquidity": null,
  "observed_at": "2026-11-06T17:59:40.000Z",
  "reference_observed_at": "2026-11-06T17:58:05.000Z",
  "reference_age_seconds": 135,
  "start_time": "2026-11-07T00:30:00.000Z",
  "live": false
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/arbitrage?limit=25" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "market": "spread",
  "period": "full_game",
  "player": null,
  "margin": 0.0123,
  "legs": [
    { "book": "bovada", "side": "home", "line": -3.5, "american": 105, "stakeFraction": 0.4938 },
    { "book": "prophetx", "side": "away", "line": 3.5, "american": 100, "stakeFraction": 0.5062 }
  ],
  "pushPossible": false,
  "legGapSeconds": 12,
  "stale": false,
  "review": false
}

{
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "market": "total",
  "period": "full_game",
  "player": null,
  "low": 224.5,
  "high": 226.5,
  "width": 2,
  "cost": 0.0455,
  "legs": [
    { "book": "bovada", "side": "over", "line": 224.5, "american": -110 },
    { "book": "prophetx", "side": "under", "line": 226.5, "american": -110 }
  ]
}

curl -s "https://unerring-api.liam-banks2004.workers.dev/v1/holds?books=bovada,prophetx" \
  -H "Authorization: Bearer $UNERRING_KEY"

{
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "market": "moneyline",
  "period": "full_game",
  "line": null,
  "player": null,
  "hold": 0.0148,
  "best": [
    { "book": "bovada", "side": "home", "american": -102, "fairProbability": 0.4976 },
    { "book": "prophetx", "side": "away", "american": -104, "fairProbability": 0.5024 }
  ]
}

{
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "market": "moneyline",
  "period": "full_game",
  "line": null,
  "exchange": "prophetx",
  "side": "home",
  "american": -108,
  "liquidity": 1250,
  "sportsbook": "bovada",
  "sportsbookAmerican": 105,
  "improvement": 0.021
}

{
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "market": "total",
  "period": "full_game",
  "line": 224.5,
  "player": null,
  "promo": { "book": "bovada", "side": "over", "line": 224.5, "american": -110, "decimal": 1.9091 },
  "hedges": [
    { "book": "pinnacle", "side": "under", "line": 224.5, "american": -104, "decimal": 1.9615, "impliedSum": 1.0336 }
  ],
  "event_name": "Boston Celtics @ Charlotte Hornets",
  "home": "Charlotte Hornets",
  "away": "Boston Celtics",
  "start_time": "2026-11-07T00:30:00.000Z",
  "status": "scheduled",
  "player_name": null
}

{
  "book": "prizepicks",
  "bookName": "PrizePicks",
  "eventId": "evt_0h7k2m9q4x1tzb",
  "sport": "nba",
  "player": "J. Example",
  "team": "Boston Celtics",
  "market": "player_points",
  "line": 27.5,
  "variant": "standard",
  "side": "over",
  "multiplier": null,
  "fairProbability": 0.5612,
  "edge": 0.0146,
  "threshold": 0.5466,
  "basis": "power_table",
  "references": ["pinnacle", "fanduel"],
  "reason": null,
  "observedAt": 1793987890000
}

No key needed

curl -s "https://unerring-api.liam-banks2004.workers.dev/public/coverage"

{
  "generated_at": "2026-11-06T18:00:00.000Z",
  "totals": {
    "books": 100,
    "expected": 80,
    "feeding": 3,
    "stale": 1,
    "no_data": 76,
    "not_expected": 20,
    "with_ev_rows": 2
  },
  "unresolved_books": {},
  "books": [
    {
      "id": "prophetx",
      "name": "ProphetX",
      "kind": "exchange",
      "status": "active",
      "state": "feeding",
      "ev_role": "reference",
      "ev_weight": 50,
      "family": null,
      "source": "prophetx",
      "last_seen": "2026-11-06T17:59:40.000Z",
      "events": 58,
      "markets": 312,
      "prices": 624,
      "leagues": ["nba", "nhl"],
      "ev_rows": 118,
      "positive_ev_rows": 6,
      "reason": null,
      "note": null
    }
  ]
}

Stream: connecting

URL wss://unerring-api.liam-banks2004.workers.dev/v1/stream

The stream needs the stream feature: Syndicate (10 sockets per account) or Enterprise (50). A connection costs 1 credit, then 1 credit for each minute it stays open. On an unlimited plan that doesn't touch your balance, but a key's monthly cap still counts it.

Deltas go out when a collector's read changes something, so their rate follows how often each venue is read, not a fixed tick.

From a server, send the key as a header. A browser can't set a header on a WebSocket, so it sends the key in its first message. A key in the URL is refused with 400 api_key_in_url.

// Node, with the ws package
import WebSocket from "ws";

const ws = new WebSocket("wss://unerring-api.liam-banks2004.workers.dev/v1/stream", {
  headers: { Authorization: `Bearer ${process.env.UNERRING_KEY}` },
});

// Browser: authenticate in the first message
const ws = new WebSocket("wss://unerring-api.liam-banks2004.workers.dev/v1/stream");
ws.onopen = () => ws.send(JSON.stringify({ type: "auth", api_key: key }));

A key with an IP allowlist has to use the header. The first-message route has no address to check against the list, so it fails with close code 4001.

An open connection is checked again each billing minute, so a revoked key or a changed plan takes effect without a reconnect.

A client that handles gaps

let lastSeq = 0;

ws.onmessage = ({ data }) => {
  const message = JSON.parse(data);
  switch (message.type) {
    case "welcome":
      ws.send(JSON.stringify({ type: "subscribe", leagues: ["nba", "nhl"], markets: ["main"] }));
      break;
    case "snapshot":
    case "delta":
    case "event":
    case "clocks":
      if (lastSeq && message.seq !== lastSeq + 1) ws.send(JSON.stringify({ type: "resync" }));
      lastSeq = message.seq;
      apply(message);
      break;
    case "heartbeat":
      if (message.seq > lastSeq) ws.send(JSON.stringify({ type: "resync" }));
      break;
  }
};

Stream: messages

From you

You can send at most one subscribe or resync a second. A faster one gets an error with code rate_limited and is not acted on.

Subscribing with no leagues and no event_ids means the whole board. markets defaults to main and periods to full_game. Use props, player_* or all to get player markets.

From the server

{ "type": "welcome", "connection_id": "con_5e2c9a7f1b3d4860", "plan": "syndicate", "heartbeat_ms": 15000, "credits_remaining": null, "capabilities": ["snapshot_fragments_v1", "subscription_resume_v1", "clocks_v1"] }

{ "type": "subscribed", "leagues": ["nba"], "markets": ["main"] }

{ "type": "snapshot", "data": [], "part": 1, "parts": 1, "seq": 1 }

{
  "type": "delta",
  "ts": "2026-11-06T18:00:05.000Z",
  "changes": [
    {
      "event_id": "evt_0h7k2m9q4x1tzb",
      "book": "prophetx",
      "id": "mkt_0k2v9qa1x7m3pc",
      "key": "total",
      "period": "full_game",
      "line": 224.5,
      "player": null,
      "suspended": false,
      "outcomes": [
        { "id": "sel_1f8s2ld0q9w4ze", "side": "over", "name": "Over", "point": 224.5, "price": -108, "liquidity": 840, "multiplier": null },
        { "id": "sel_0p3n7ty5h2c6vb", "side": "under", "name": "Under", "point": 224.5, "price": -112, "liquidity": 1120, "multiplier": null }
      ]
    }
  ],
  "removed": ["mkt_2w7e1q9r5t3yui"],
  "seq": 2
}

{ "type": "event", "event_id": "evt_0h7k2m9q4x1tzb", "status": "live", "score": { "home": 12, "away": 9 }, "seq": 3 }

{ "type": "heartbeat", "seq": 3 }

A market in changes sends every field, with null where a REST answer would leave the field out, and each one is tagged with event_id and book. removed isn't filtered by your subscription, so ignore ids you don't hold. Any filters you set apply to changes.

Clocks

A delta goes out when something about a market changes. When a book is read again and its price hasn't moved, nothing changes, so nothing is sent, and the observed_at you hold stops moving even though the book is still quoting that price. Judged by that held clock, the price would look stale after 900 seconds (90 once live) when it isn't.

Subscribe with "capabilities": ["clocks_v1"] to hear about those reads. Each clocks message lists, per book, a clock (observed_at) and either event_ids or market_ids:

• event_ids: every market of that book in those games is at least that new. Move each one you hold there to it.
• market_ids: only those markets. Used when a book's markets in a game were read at different times.

Move a clock forward only, never back, and leave an outcome's own observed_at as it is. Games and markets are named only if you held them when their clock was queued. One you have dropped since can still appear, so ignore ids you don't hold. You get at most one clocks message every 5 seconds, each at most 64 KiB. What doesn't fit waits its turn, oldest first, and goes at its latest clock. With nothing else to send, a waiting clock goes at the next heartbeat, so it can take about 15 seconds. With a very large subscription, a turn can take longer. They cost nothing extra. Without clocks_v1 you never get one.

Judge a price's age on the server's clock, not your device's: take ts on messages, or as_of on REST answers, as the server's time.

{
  "type": "clocks",
  "ts": "2026-11-10T12:00:05.000Z",
  "books": {
    "pinnacle": [
      { "observed_at": "2026-11-10T12:00:01.000Z", "event_ids": ["evt_0h7k2m9q4x1tzb", "evt_3n8c5v1x7z2qwe"] }
    ],
    "prophetx": [
      { "observed_at": "2026-11-10T11:59:58.000Z", "market_ids": ["mkt_0k2v9qa1x7m3pc"] }
    ]
  },
  "seq": 4
}

Stream: sequence numbers

snapshot, delta, event and clocks each raise seq by exactly 1 per connection, starting from 1. A heartbeat repeats the latest value without raising it. So a jump, or a heartbeat above the last seq you saw, means you missed something: send resync.

seq starts again on a new connection. If nothing at all arrives for about 45 seconds, treat the connection as dead and reconnect with a backoff, which costs another connect credit.

Stream: close codes

How EV is worked out

In short: each price at each book is compared with a fair probability, taken from what the sharp references say with their margin removed. A book never contributes to its own fair price, and neither does any book sharing its odds platform. EV figures compare prices at the moment they were read. They are estimates, not a promise of return.

These settings are fixed. The API has no parameter to change the devig method, the weights or the gates.

References and weights

Every book has a role, reported as ev_role.

The references below are rules in the system. Being listed doesn't mean a book is feeding. Check coverage for that: a reference with no prices has no effect.

Main markets are moneyline, spread, total and three-way. Player markets are anything with a player. Team totals and alternates fall into neither, so only references marked "All markets" count for them.

To count on a given market line, a reference has to meet all of these:

• It prices every side of the market.
• Its margin is no more than 20%.
• A sportsbook's margin is at least 0.1%, because a sportsbook pair with no margin is suspect.
• An exchange's sides add up to at least 98%.
• An exchange has depth on all sides, the deepest side has no more than twice the depth of the thinnest, and the total meets the minimum above.

Families

Books on one odds platform are one opinion. Within a family, the members' no-vig chances are averaged, and the family's weight is its largest member's weight, not the sum. A price is never compared with its own book or with any member of its own family.

Any other book is a family of one.

Changed on 10 Nov 2026: the six books that carry Kambi's shared price stream are one family, kambi. Arbitrage, middle and promo pairs between any two of them are no longer shown, including betPARX, Gun Lake and Four Winds, which were families of one. Bally Bet, Desert Diamond Sports and LeoVegas left betrivers, so their pairs with BetRivers, Betly and SugarHouse are now shown. The family field in the coverage report changes for those six books. Consensus and +EV are unchanged, since none of the six carries weight.

Gates

Before anything is computed, a price is dropped if any of these is true:

• It isn't valid American odds, or it has no event, market or side.
• Its market is suspended.
• Its read time is more than 5 seconds in the future.
• It is a pre-game price and the start time has passed.

Only the newest price for each book, side and line is kept.

Age is measured from when a price was observed, so a failing source goes stale rather than looking current. Old prices are kept and scored at their real age, but a stale row never counts as +EV.

• The price being scored is stale when it is more than 15 minutes old before the game, or more than 90 seconds old once the game has started.
• A reference setting the fair price may be up to 30 minutes old before the game, and 90 seconds once it has started. The 30 minutes is an interim limit, and it will tighten back to 15 once Pinnacle's prices are read more often. Pinnacle's copies currently sit 20 to 30 minutes old. On the live board on 8 November, +EV rows on a current price whose reference was 15 to 30 minutes old still beat Pinnacle's closing line 78% of the time (279 rows, average closing-line value 0.95%). Rows whose reference was older than 30 minutes lost (14 rows, −2.34%). So a +EV row can rest on a reference whose own entry in quote_observations shows quality.stale: true. That flag honestly applies the general 15-minute rule to every observation. Whether the row counts is decided by its own stale and reference_age_seconds.
• Once a game's start time has passed, a price or reference read before kickoff is stale, whatever the event's status says. Anything read after kickoff gets the 90-second limit, even while the status still says the game hasn't started. A start time that is only a "to be confirmed" placeholder doesn't count as kickoff until a full day after it, since the placeholder names the day. A placeholder can also be a real kickoff, such as midnight Eastern for a game in Hawaii. So every row on such a game is listed but never counted, with stale_reason: start_time_to_be_confirmed.

A fair price is set only by references within their limit whenever any qualify. When none do, the price is scored against the older ones and the row is stale. Each row's stale_reason says why.

A scored row must then pass three plausibility checks to appear on the default /v1/ev board. All of them still appear with scored=true, marked plausible: false.

• EV is at most 25%, or at most 10% when only one family set the fair price.
• On a game market, the book also offers every other side, and its sides add up to between 100% and 125%. Player markets skip this check.
• The row isn't stale.

Consensus and devig

1. Gather the sides of one market line. Spreads pair at opposite handicaps; everything else pairs at one line. A market with only one side isn't scored.
2. For each price being scored, take the qualifying references outside its book and its family. If there are none, that price isn't scored.
3. Remove each reference's own margin from its own prices with Shin's method. On a two-way market that takes half the margin off each side's implied probability. On a three-way market it allows for some bettors knowing more than the book. A wide book's margin can't spill onto the others. Shin was chosen on our own data. Against low-margin exchange prices on the same lines (615 pairs on 8 Nov), it had the smallest error and almost no favourite bias. The multiplicative method, dividing each side by the total, under-rated favourites by 0.35 points. The power method over-corrected.
4. Average the no-vig chances inside each family, then take a weighted average across families, using each family's weight. That is the fair probability.
5. Score the price: EV = fair probability × decimal odds − 1. Edge = fair probability − 1 / decimal odds. Kelly = EV / (decimal odds − 1), kept between 0 and 1. At an exchange, the decimal odds are those after its published fee.

Exchange fees

An exchange's posted prices leave out its fee, so EV at an exchange uses the price after the fee the venue itself publishes. The posted prices still set fair prices as they are.

Only a published, cited fee counts. An exchange whose fee isn't on file, or a league whose schedule isn't modelled (ProphetX NHL), gets fee_verified: false. Its EV is shown before any fee, and the row is never plausible, so it never counts as +EV. It stays visible with scored=true and its raw prices stay on /v1/odds, the same way Kalshi and Polymarket are held back.

Arbitrage, middles, holds

Arbitrage pairs the two sides of a two-way market across different families. Each book must quote both sides, adding up to between 100% and 125%, and the two legs' start times must agree within 3 hours. Margin is 1 / (1 / decimal A + 1 / decimal B) − 1, using each exchange leg's price after its published fee, and anything above 15% is dropped as not credible. Every leg must be current (see Leg ages).

Middles look for over the lower total and under the higher, or spreads where home −3.5 and away +4.5 both win on a 4-point home win. The legs must be from different families, and the window must contain a result. cost must be at most 10%, and not below −15%.

Holds take the best price on each side among books that quote both sides, adding up to between 100% and 125%. hold is the sum of the implied probabilities minus 1, and fairProbability removes that margin multiplicatively.

Leg ages

Arbitrage, middles, holds, hedges and smart money judge every leg by the age rule a priced quote gets on /v1/ev (see Gates). Every leg is a price someone has to take, so the 30-minute reference allowance never applies. A leg is stale when it is more than 15 minutes old before the game, more than 90 seconds old once the game has started, or was read before a start that has passed. A placeholder start time doesn't count as kickoff for a day, but because it may be a real kickoff, a leg on such a game is never current either. Its staleReason is start_time_to_be_confirmed.

• By default only rows whose every leg is current are listed. Holds take each side's best current price.
• Arbitrage and middles also price each exchange leg after its published fee, and hold back rows with a leg at an exchange whose fee isn't verified, as /v1/ev does.
• include_stale=true also returns the held-back rows, flagged feeUnverified, and rows with an old leg, each leg at its real age with a staleReason of price_older_than_limit or price_read_before_start. On holds it lets an old price be the best price again.
• Paging pins every page to the first page's as_of, so ages are measured from the same moment throughout one walk.

On the live board at 20:50Z on 8 November, 307 of 332 arbitrage rows, 73% of middles and 42% of holds rested on a leg older than this. Nearly all were soft-book prices read hours earlier, that had since moved.

Pick'em pricing

Pick'em edges require a verified entry payout and a fair probability. Apps with verified per-pick payouts expose that factor as multiplier. Dabble's operator price is also returned in that field, but its relationship to the entry payout is unverified, so its threshold and edge are withheld. /v1/dfs estimates the line's fair probability from sharp books and derives a break-even only when the payout is verified. It uses a different recipe from the +EV board: each book is devigged first, then averaged, using the power method and a maximum margin of 10%.

• Books with a price at the exact line are used, and they are never blended with interpolated books.
• If none has the exact line, each book can interpolate between its own lines on either side, on a log-odds scale. It can reach 0.5 of a stat for shots on goal, and 2.5 for yards, points and points + rebounds + assists. Other stats can reach 1 when the line is under 10, and 2.5 otherwise.
• Interpolated books must agree within 3 percentage points, or the row reports low_confidence. With no usable book it reports no_sharp_books.
• Books at the exact line that are 6 or more percentage points apart on the under report books_disagree: one of them is pricing something else or is out of date. On the live board on 8 Nov, same-line sharp books were 1.1 points apart at the median and 4.3 at the 99th percentile.

Break-even comes from the app's payout table, using its cheapest all-must-hit entry: multiplier^−1/picks. These tables are the apps' published figures, which can change.

On Sleeper Picks, Chalkboard, Boom Fantasy, ParlayPlay and HotStreak, each pick has its own multiplier, so the threshold is 1 / multiplier and basis is per_pick_multiplier. With no published multiplier, edge is null. Other apps have basis: "none". That includes Dabble for now: its picks carry prices that vary pick by pick, and how those prices change a payout isn't verified, so its threshold and edge are null. Its line, multiplier, fairProbability and references are still sent.

Known limits

• Native prediction contracts and BBO are raw observations with no verified quote-update clock, execution, payout or financial EV model. Their separate counts do not imply canonical game-price coverage.
• /v1/scores has no finished games, because a game leaves the board when a source reports it final.
• clock on events and team_id on players are always null.
• Webhooks exist for line moves on plans with the webhooks feature, at 1 credit a delivery, but are set up by the operator for now. Each POST has X-Unerring-Signature: t=<seconds>,v1=<hex>, the HMAC-SHA256 of <t>.<body> with your signing secret. A target that fails 20 times in a row is switched off.
• Prices are polled from each venue, so they are minutes old rather than milliseconds. Pinnacle's public data is held by its CDN for up to 15 minutes, so an edge against it can already be gone. updated_at on each book shows when its prices were read, and /v1/ev ages them from when they were really fetched.
• History covers full-game moneyline, spread and total markets only, for 30 days.
• /v1/arbitrage, /v1/middles, /v1/holds, /v1/smart-money, /v1/hedges and /v1/dfs use different field naming from the rest of the API, as noted under Computed.
• Bet links, deep links and per-state pricing are not offered.
• Coverage changes as collectors are added or a venue blocks reads. Rely on /public/coverage, not on any list in these docs.

Changes

10 Nov 2026: stream clocks

• The stream can now tell you when a price was read again and found unchanged. Subscribe with "capabilities": ["clocks_v1"] to get clocks messages. Each gives, per book, a clock and the games or markets it applies to. Without them, a price re-read at the same number sends nothing, so the observed_at you hold stops moving. They are opt-in, so a client that doesn't ask sees no new message type. At most one is sent every 5 seconds per connection, up to 64 KiB each. Credits are unchanged. The welcome message's capabilities list now includes clocks_v1.
• On the site, the odds screen asks for them. The grid now never highlights a stale price as the best, by the same rule as /v1/best-lines, judged on the server's clock, and draws again when the earliest best price would go stale. So the Best view and the grid agree.

10 Nov 2026: best lines are fresh

• /v1/best-lines takes the best fresh price on each side: a price past its age limit never sets a best line. A game whose only prices are stale isn't listed. In a game that is listed, a side or a whole market with no fresh price is left out, so a two-way market can come back with one side, and books_quoting counts only books with a fresh price. The NDJSON export follows the same rule. Credits are unchanged.
• include_stale=true on /v1/best-lines lets stale prices compete, and every entry in observations now carries stale. It no longer lists games whose status is stale there: name such a game in event_ids.
• On the site, the odds screen's Best view follows this rule. The grid's highlighted best price doesn't judge age yet, because the stream doesn't carry a re-read that found the same price. So the two can differ until it does.

10 Nov 2026: bookmaker clocks

• bookmaker.observed_at, updated_at and quality on /v1/odds, /v1/props, /v1/events/{id}/odds and stream snapshots now come from the oldest clock among the markets and outcomes returned for that book. They used to come from the book's latest read, so a request for props or alternates could get a bookmaker marked fresh around markets hours old. A client that filters bookmakers on quality.stale will see more of them stale where a book's markets were read at different times, and fewer where only markets you didn't ask for were old.
• New bookmaker.book_observed_at: the book's newest copy. received_at and time_basis now describe that copy. time_basis is snapshot or read; it is never venue.
• venue_updated_at is no longer sent for Onyx or for Crypto.com (from Covers): their stamps don't move when their prices do. Nor for Fanatics Markets, whose lastSeenAt isn't shown to be a price-change time. History recorded before this change still carries them.
• Hard Rock is clocked at its copy's own age, and a game it re-sends from its last read keeps that copy's clock.
• Kambi books (LeoVegas, Gun Lake, BetParx, Four Winds and the rest) are clocked at their CDN copy's own age, from its Date and Age, futures included.
• Betway, LetsBetMD, BetUS, PointsBet CA, Betinia, Monopoly, Dabble and Sleeper now carry their copy's own clock, from its Date and Age, where they used to be clocked at our read time. The first four keep that clock when they send a copy again from their cache, where they used to send it at the time it was first read.