API reference · Receipts

Attest an action

POST/v1/receipts/attest

Record and sign that you acted on an event, bound to the event's hash.

On this page

Auth. An API token: Authorization: Bearer lb_… (create one). Signed-in web sessions work too.

Limits. Counts against your plan's API requests (60, 600 or 3,000 a minute on Free, Builder and Standard).

Parameters

Body

Name	Type	Required	Description
`evt_id`	string	yes	The event you acted on (`evt_…`).
`hash`	string	no	The event hash you hold; refused with `409` when it differs from the record.
`action`	object	yes	Your action as JSON, at most 4 KiB. Private to you; never put venue credentials in it.
`t_acted`	integer	no	When you acted, ms epoch; default the time of the call.

Request

Terminal

curl -X POST "https://api.langbot.ai/v1/receipts/attest" \
  -H "Authorization: Bearer $LANGBOT_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"evt_id": "evt_01K7Q0000000000000000000A2", "hash": "5d0e05c3…", "action": {"side": "yes", "qty": 20, "price": 0.57}, "t_acted": 1760050125000}'

Python

from langbot import LangbotClient

async with LangbotClient() as lb:  # reads LANGBOT_API_TOKEN
    row = await lb.attest("evt_01K7Q0000000000000000000A2", {"side": "yes", "qty": 20}, t_acted=1760050125000)
    print(row["id"], row["signature"])

TypeScript

const res = await fetch("https://api.langbot.ai/v1/receipts/attest", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.LANGBOT_API_TOKEN}`, "Content-Type": "application/json" },
  body: JSON.stringify({"evt_id": "evt_01K7Q0000000000000000000A2", "hash": "5d0e05c3\u2026", "action": {"side": "yes", "qty": 20, "price": 0.57}, "t_acted": 1760050125000}),
});
console.log(await res.json());

Response

201 Created

JSON

{ "id": "att_01K7Q…", "user_id": "usr_…", "evt_id": "evt_01K7Q0000000000000000000A2", "event_hash": "5d0e05c3…", "action_hash": "9f2c…", "t_acted": 1760050125000, "created_at": 1760050125500, "key_id": "56475aa75463474c", "signature": "…" }

Errors

Status	`code`	When
404	`not_found`	Unknown event.
409	`conflict`	`hash` does not match the record.
413	`too_large`	`action` is over 4 KiB.
401	`auth_required`	No token was sent.
401	`token_invalid`	The token was not recognised (mistyped, revoked or expired).
422	`validation_error`	A parameter failed validation; `detail[].loc` names it.
429	`rate_limited`	Over your request budget; wait `Retry-After` seconds.

Every error body is {"detail": …, "code": "…"}; branch on code. All codes: Errors.