Stacked SRM (TAB)

Place multiple Same Race Multis on the same race in one betslip, in a single API call. Each SRM is priced and placed independently - TAB returns one bet ID per SRM. Same behaviour as stacking SRMs in TAB's web betslip and clicking "Place all".

Bookmaker support: TAB only. Other bookmakers' APIs don't currently expose a stacked-bet shape; for those, place each SRM via a normal category: "racing" + is_same_event_multi: true request against /v3/place_bet.

POST /v3/stacked_srm is the new home for this endpoint. It uses the same async contract as /v3/place_bet: a 202 response in ~100ms with a correlation_id, then poll POST /api/bet_status (or receive a signed webhook at callback_url) for the actual stacked-result payload. The result field carries the same shape the legacy /v2/place_bet stacked_srm branch used to return inline - drop-in for existing parsing code.

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When to use this

• You want to place 2+ SRMs on the same race quickly without 2+ round-trips.
• Each SRM should be priced + placed independently (separate bet IDs, separate stakes, separate target_odds checks).
• One bet failing should not cancel the others.

If you only want one SRM, use POST /v3/place_bet with category: "racing" and is_same_event_multi: true - this stacked endpoint rejects single-bet requests with a 400.

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Endpoint - POST /v3/stacked_srm {#v3-stacked-srm}

Request

bets[] entry

legs[] entry (per SRM)

Validation (before the 202)

• session_id must resolve to a TAB session → otherwise 400.
• bets length >= 2 → for a single SRM, hit /v3/place_bet with category: "racing" and is_same_event_multi: true instead.
• Each bets[i].legs length >= 2.
• Each bets[i].stake is positive.

Response (202)

Standard v3 async envelope:

{
  "status":         "pending",
  "correlation_id": "9b3c…uuid…",
  "session_id":     "uuid",
  "bookie":         "tab",
  "username":       "user@example.com",
  "submitted_at":   "2026-05-14T10:00:00.000Z",
  "timeout_at":     "2026-05-14T10:05:00.000Z",
  "callback_url":   null
}

Retrieve the result by polling POST /api/bet_status with the correlation_id, or via webhook if you passed callback_url. Signature verification, retry behaviour, and status values are identical to every other v3 endpoint - see the Async API (v3) guide.

State-mutating - same hazard as /v3/split_bonus_bet. Once the 202 lands, the bets are queued for TAB's betslip. Never re-submit on a network blip - re-poll /api/bet_status with the correlation_id instead. Persist the correlation_id from the 202 immediately, and on any client-side error surface that ID to the user rather than re-firing the request.

result payload

{
  "success": true,
  "placed": 2,
  "failed": 0,
  "results": [
    {
      "success": true,
      "bet_id": "19349371189856901",
      "odds": 12.09,
      "stake": 1.00,
      "market": "srm",
      "track": "Albany",
      "race_num": 8,
      "legs": [
        {"runner": "Cheyne Bay", "position": "win", "number": 4, "odds": 3.9, "proposition_id": 167861},
        {"runner": "Angel Shame", "position": "top2", "number": 7, "odds": 3.1, "proposition_id": 168871}
      ],
      "error": null
    },
    {
      "success": true,
      "bet_id": "19349371189856902",
      "odds": 8.40,
      "stake": 1.00,
      "market": "srm",
      "track": "Albany",
      "race_num": 8,
      "legs": [...],
      "error": null
    }
  ]
}

Failure modes

• Whole stack rejected before placement - result.success: false, no results (or empty). Something failed pre-confirm: proposition resolution, target-odds floor, bonus-token allocation, or TAB enquiry/betslip status. Nothing was placed.
• Per-bet failure during confirm - result.success: true with failed > 0. TAB accepted the betslip but rejected one or more bets at placement. Successful bets are placed; failures show in results[i].error.

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Examples

cURL - two SRMs on Albany R8

curl -X POST https://api.b337.ai/v3/stacked_srm \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "session_id": "uuid-string",
    "track": "Albany",
    "race_num": 8,
    "race_type": "(R)",
    "date": "2026-04-26",
    "bets": [
      {
        "stake": 1.0,
        "target_odds": 10.0,
        "legs": [
          {"runner": "Cheyne Bay", "position": "win"},
          {"runner": "Angel Shame", "position": "top2"}
        ]
      },
      {
        "stake": 1.0,
        "target_odds": 6.0,
        "legs": [
          {"runner": "Cheyne Bay", "position": "win"},
          {"runner": "Buffalo Theory", "position": "top3"}
        ]
      }
    ]
  }'

Python - submit + poll

import requests, time

API_KEY = "YOUR_API_KEY"
BASE = "https://api.b337.ai"
HEADERS = {"X-API-Key": API_KEY, "Content-Type": "application/json"}

# 1. Submit (202 in ~100ms)
submit = requests.post(
    f"{BASE}/v3/stacked_srm",
    headers=HEADERS,
    json={
        "session_id": SESSION_ID,
        "track": "Albany",
        "race_num": 8,
        "race_type": "(R)",
        "date": "2026-04-26",
        "bets": [
            {
                "stake": 1.0,
                "target_odds": 10.0,
                "legs": [
                    {"runner": "Cheyne Bay", "position": "win"},
                    {"runner": "Angel Shame", "position": "top2"},
                ],
            },
            {
                "stake": 1.0,
                "target_odds": 6.0,
                "legs": [
                    {"runner": "Cheyne Bay", "position": "win"},
                    {"runner": "Buffalo Theory", "position": "top3"},
                ],
            },
        ],
    },
).json()

cid = submit["correlation_id"]
timeout_at = submit["timeout_at"]
# IMPORTANT: persist cid here before doing anything else. State-mutating -
# if the loop below breaks, we re-poll, we never re-submit.
deadline = time.mktime(time.strptime(timeout_at[:19], "%Y-%m-%dT%H:%M:%S"))

# 2. Poll /api/bet_status until done
while time.time() < deadline:
    r = requests.post(
        f"{BASE}/api/bet_status",
        headers=HEADERS,
        json={"correlation_ids": [cid]},
    ).json()
    entry = r["statuses"][0]
    if entry["status"] == "completed":
        data = entry["result"]  # same shape as the old v2 stacked_srm response
        print(f"placed={data['placed']} failed={data['failed']}")
        for i, bet in enumerate(data["results"]):
            if bet["success"]:
                print(f"  bet {i}: OK id={bet['bet_id']} odds={bet['odds']}")
            else:
                print(f"  bet {i}: FAIL {bet['error']}")
        break
    if entry["status"] in ("timeout", "unknown"):
        print(f"poll failed: {entry['status']}; correlation_id={cid} for manual recheck")
        break
    time.sleep(2)

With a bonus bet on one of the bets

{
  "session_id": "...",
  "track": "Albany",
  "race_num": 8,
  "date": "2026-04-26",
  "bets": [
    {
      "stake": 1.0,
      "target_odds": 10.0,
      "legs": [{"runner": "X"}, {"runner": "Y", "position": "top2"}]
    },
    {
      "stake": 25.0,
      "bet_type": "bonus",
      "target_odds": 8.0,
      "legs": [{"runner": "X"}, {"runner": "Z", "position": "top3"}]
    }
  ]
}

Bonus tokens: if multiple bets in the stack use bet_type: "bonus", they're allocated different tokens serially before submission. If any bonus bet can't get a matching token (e.g. no token <= stake), the entire stack is rejected before placement (no partial bets).

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Notes & limits

• Same race only. All bets in bets[] must be on the same (track, race_num, race_type, date). Different races → use multiple separate calls.
• Min 2 bets. For a single SRM use /v3/place_bet with category: "racing" + is_same_event_multi: true.
• Target odds floor is per-bet. Each bet has its own target_odds. If any bet's enquiry/betslip price falls below its floor, the whole stack is aborted before placement.
• Pre-flight failures abort the stack. If runner matching fails for any leg (e.g. typo), or any bet has zero proposition IDs, the stack is rejected before any TAB betslip call.
• Latency: 3 round-trips total inside the bot (pricing enquiry → betslip enquiry → confirm) regardless of stack size - this happens after the 202, so it doesn't block your client.
• Recording: each successfully-placed SRM is written to the bets table as its own row with bet_type=srm.

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Deprecated: POST /v2/place_bet with category: "stacked_srm"

⚠️ Deprecated - sunset 2026-05-17. The stacked_srm branch of POST /v2/place_bet still works but now returns deprecation response headers:

Deprecation: true
Sunset: Sun, 17 May 2026 00:00:00 GMT
Link: </v3/stacked_srm>; rel="successor-version"

After 17 May 2026 the stacked_srm branch will return HTTP 410. Other categories on /v2/place_bet (racing, sports, multi, betfair) are not affected by this sunset.

Migrate to POST /v3/stacked_srm - same payload minus the category field (the endpoint is the discriminator now), plus optional callback_url. The result payload shape is identical.

Legacy request (still works until 2026-05-17)

curl -X POST https://api.b337.ai/v2/place_bet \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "session_id": "uuid-string",
    "category": "stacked_srm",
    "track": "Albany",
    "race_num": 8,
    "race_type": "(R)",
    "date": "2026-04-26",
    "bets": [
      {"stake": 1.0, "target_odds": 10.0,
       "legs": [{"runner": "Cheyne Bay", "position": "win"},
                {"runner": "Angel Shame", "position": "top2"}]},
      {"stake": 1.0, "target_odds": 6.0,
       "legs": [{"runner": "Cheyne Bay", "position": "win"},
                {"runner": "Buffalo Theory", "position": "top3"}]}
    ]
  }'

Returns the same result-payload shape shown under result payload above, but inline synchronously (no correlation_id, no poll step).

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Next Steps

• Async API (v3) guide - Polling and webhook semantics in detail
• Place Bet (v3) - Single bets, SGM, parlay, single SRMs
• Bonus Bets & Promos - Manage bonus bet tokens used by stacked SRMs