Place Bet — `POST /v3/place_bet`

Asynchronous bet placement. Returns 202 Accepted in ~100 ms with a correlation_id; the actual bet result is delivered via polling or a webhook.

New here? Read Async API first — it covers the 4-actor pipeline (your script → API → your client → bookie), the correlation_id contract, and has the copy-paste CLAUDE.md snippet for AI assistants. All /v3/* endpoints follow the same model.

Racing

Important. Use POST /v3/place_bet (async). The synchronous /v2/place_bet is deprecated — it holds the HTTP connection open up to 30s and 504s frequently. Hitting it now returns 410 Gone with a pointer to v3:
{ "error": "deprecated", "use": "POST /v3/place_bet" }

Auth

X-API-Key: <your-api-key>
Content-Type: application/json

Every request must also include a session_id belonging to the account that owns the API key.

Single bet (win / place)

curl -X POST https://api.b337.ai/v3/place_bet \
  -H "X-API-Key: <your-key>" \
  -H "Content-Type: application/json" \
  -d '{
    "session_id": "11142",
    "category": "racing",
    "track": "Flemington",
    "race_num": 4,
    "race_type": "(R)",
    "date": "2026-05-25",
    "runner": "Verry Elleegant",
    "market": "win",
    "stake": 25.00,
    "target_odds": 4.20
  }'

Response (202):

{
  "status": "pending",
  "correlation_id": "9b3c…uuid…",
  "submitted_at": "2026-05-25T03:11:00.000Z",
  "timeout_at": "2026-05-25T03:12:00.000Z"
}

SRM — Same Race Multi

Set is_same_event_multi: true and pass a legs array. runner / market move into each leg.

{
  "session_id": "11142",
  "category": "racing",
  "track": "Flemington",
  "race_num": 4,
  "date": "2026-05-25",
  "is_same_event_multi": true,
  "legs": [
    { "runner": "Verry Elleegant", "market": "win" },
    { "runner": "Nature Strip",   "market": "place" }
  ],
  "stake": 10.00,
  "target_odds": 12.00
}

For stacked SRMs (TAB only) see the dedicated POST /v3/stacked_srm endpoint.

Exotics (tote pools)

Exacta, Quinella, Duet, Trifecta, First 4 and the multi-race pools (Quaddie, Treble, Big 6, …) are a separate category — category: "exotic", with legs that are RACES rather than selections, and no price at all. See the Exotics tab above.

Field reference — Racing

Field	Type	Required	Notes
`session_id`	string	✅	Must belong to caller's API key and be active.
`category`	`"racing"`	✅	Constant.
`track`	string	✅	e.g. `"Flemington"`, `"Randwick"`.
`race_num`	int	✅	Race number.
`race_type`	string	optional	`"(R)"` thoroughbred (default), `"(G)"` greyhound, `"(H)"` harness.
`country`	string	recommended	Region code — `"au"`, `"nz"`, `"gb"`, `"us"`, … Send it together with `date` and we resolve the exact race against our race spine and match the bookmaker's exact track naming — this disambiguates same-named tracks across regions and days. Omit it and we fall back to looser name matching.
`date`	string	✅	`YYYY-MM-DD` — the race's actual date. Supply it (with `country`) so we never match the wrong day.
`runner`	string	single only	Runner name as the bookie lists it.
`market`	string	single only	`"win"` or `"place"`. `each_way` is not supported and will 400.
`is_same_event_multi`	bool	for SRM	If true, supply `legs[]` instead of `runner`/`market`.
`legs`	array	for SRM	`[{ runner, market }, …]`.
`stake`	number	✅	Dollars.
`target_odds`	number	✅	Floor — bet rejected below this.
`max_odds`	number	optional	Ceiling — bet auto-rejected if the live matched price is above this. Guards against wrong-line / wrong-runner matching. Omit / null = no ceiling. Must be ≥ `target_odds`.
`use_boost`	bool	optional	Apply an odds boost if available.
`betboost`	bool	optional	Apply a boost opportunistically: attach one if the bookie offers it, otherwise place the bet unboosted. `use_boost` is strict and refuses a bet it cannot boost.
`use_bonus_bet`	bool	optional	Use bonus-bet balance.
`promo_name`	string	optional	Specific promo to attach.
`skip_if_no_promo`	bool	optional	If `true`, reject the bet when the promo isn't applicable instead of placing without it.
`callback_url`	string	optional	Webhook for async result.
`random_delay`	object	optional	`{ min, max }` — seconds the client waits before placing, drawn as `random.uniform(min, max)`. Floats allowed (e.g. `0.5`). `min` defaults to `0`; the delay is only applied when `max > 0` (omit / `max: 0` = no delay).

Common errors

Status	Body	Meaning
400	`{"error":"market not supported","market":"each_way"}`	Use win or place.
403	`{"error":"session_not_owned"}`	The `session_id` doesn't belong to this API key's account.
410	`{"error":"deprecated","use":"POST /v3/place_bet"}`	You hit `/v2/place_bet`. Migrate.

Place Bet — POST /v3/place_bet