Accreditation and access control

VENTRY has two distinct door operations, and you probably need both:

Accreditation

Happens once per attendee. The ticket QR is read and a physical wristband is linked to it. From then on, the wristband is their identity.

Zone control

Happens every time someone crosses an inner door. Only the wristband is read, and it is checked against that zone.

Scopes needed: checkins.write (requires manual activation) and, to read the history, checkins.read.

These calls go from your server, never straight from the door application. An API key embedded in a mobile app is, for practical purposes, published. Have your app talk to your backend and let the backend call VENTRY.

Accreditation

The operator scans the ticket QR and then the new wristband:

curl -X POST https://api.ventry.es/v1/tickets/TR-84213-001/check-in \
  -H "Authorization: Bearer $VENTRY_KEY" \
  -H "Idempotency-Key: 7c9e6679-7425-40de-944b-e07fc1f90ae7" \
  -H "Content-Type: application/json" \
  -d '{
    "wristband": { "nfc": "04A2B1C3D4E580", "uhf": "E28068940000501234567890" },
    "originality_signature": "3045022100AB...",
    "originality_verified": true
  }'

await fetch("https://api.ventry.es/v1/tickets/TR-84213-001/check-in", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.VENTRY_KEY}`,
    "Idempotency-Key": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    wristband: { nfc: "04A2B1C3D4E580", uhf: "E28068940000501234567890" },
    originality_signature: "3045022100AB...",
    originality_verified: true,
  }),
});

requests.post(
    "https://api.ventry.es/v1/tickets/TR-84213-001/check-in",
    headers={
        "Authorization": f"Bearer {os.environ['VENTRY_KEY']}",
        "Idempotency-Key": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
    },
    json={
        "wristband": {"nfc": "04A2B1C3D4E580", "uhf": "E28068940000501234567890"},
        "originality_signature": "3045022100AB...",
        "originality_verified": True,
    },
    timeout=15,
)

<?php
callVentry("POST", "/tickets/TR-84213-001/check-in", [
    "headers" => [
        "Idempotency-Key: 7c9e6679-7425-40de-944b-e07fc1f90ae7",
        "Content-Type: application/json",
    ],
    "body" => json_encode([
        "wristband" => [
            "nfc" => "04A2B1C3D4E580",
            "uhf" => "E28068940000501234567890",
        ],
        "originality_signature" => "3045022100AB...",
        "originality_verified" => true,
    ]),
]);

{
  "object": "checkin_result",
  "ticket_code": "TR-84213-001",
  "wristband": {
    "id": "6a3d0712a1e963300ee2cc21",
    "nfc": "04A2B1C3D4E580",
    "uhf": "E28068940000501234567890",
    "status": "active"
  }
}

The wristband is born with the zones of the ticket type plus that specific ticket’s extra_zones, and with its valid days. There is nothing to configure: it all comes from the ticket.

Field	Notes
`wristband.nfc`	Required. The identifier read from the chip.
`wristband.uhf`	Optional. If the wristband has no UHF, the NFC is reused.
`originality_signature`	Optional. Chip originality signature, in hexadecimal.
`originality_verified`	Optional. Whether that signature verified against the manufacturer’s key.

Send the originality signature even when it fails to verify. It is stored anyway, and it is what lets the organiser audit afterwards which wristbands actually got into the event.

Retries

The Idempotency-Key identifies the physical scan. Generate it when the QR is read and keep it for every retry of that accreditation:

const scanId = crypto.randomUUID();   // once, when the QR is read
await withRetries(() => checkIn(ticketCode, nfc, scanId));

scan_id = str(uuid.uuid4())   # once, when the QR is read
with_retries(lambda: check_in(ticket_code, nfc, scan_id))

$scanId = bin2hex(random_bytes(16));   // once, when the QR is read
withRetries(fn () => accredit($ticketCode, $nfc, $scanId));

If the network drops right after VENTRY redeems the ticket, the retry returns the same wristband instead of issuing a second one.

What can go wrong

Response	What happened	What to do
`404 ticket_not_found`	The code does not exist, or is outside your key’s scope	Refuse entry
`409 wristband_in_use`	That wristband is already assigned to another attendee	Take another wristband
`409 ticket_already_claimed`	The ticket was already accredited elsewhere	See below
`422 checkin_failed`	Could not be completed	Retry; if it persists, escalate

Double accreditation. When two doors try to accredit the same ticket, only one wins. The second gets 409 ticket_already_claimed and the wristband just issued is left in pending_review: it can be scanned — so security is alerted — but it cannot spend balance.VENTRY does not decide blindly which one is right: it may be the same operator retrying at another door, or a duplicated QR. A supervisor resolves it from the dashboard. Your application should show the message and ask staff to call someone, not retry.

Zone control

The operator scans only the wristband, at the door of an inner zone:

curl -X POST https://api.ventry.es/v1/access-checks \
  -H "Authorization: Bearer $VENTRY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "wristband_code": "04A2B1C3D4E580",
    "zone": "6a3d2a6ea1e963300ee2c99d"
  }'

const check = await (
  await fetch("https://api.ventry.es/v1/access-checks", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.VENTRY_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      wristband_code: "04A2B1C3D4E580",
      zone: "6a3d2a6ea1e963300ee2c99d",
    }),
  })
).json();

check = requests.post(
    "https://api.ventry.es/v1/access-checks",
    headers={"Authorization": f"Bearer {os.environ['VENTRY_KEY']}"},
    json={
        "wristband_code": "04A2B1C3D4E580",
        "zone": "6a3d2a6ea1e963300ee2c99d",
    },
    timeout=10,
).json()

$check = callVentry("POST", "/access-checks", [
    "headers" => ["Content-Type: application/json"],
    "body" => json_encode([
        "wristband_code" => "04A2B1C3D4E580",
        "zone" => "6a3d2a6ea1e963300ee2c99d",
    ]),
]);

{
  "object": "access_check",
  "allowed": true,
  "reason": "Acceso permitido",
  "attendee_name": "Ada Lovelace",
  "ticket_type": "VIP pass",
  "wristband_status": "active"
}

Denying is not an error. The response is always 200, with allowed: true or false and the reason. A 403 would mean your API key lacks permission, which is something else entirely: if you lump both cases into the same catch, you will end up denying legitimate entries when your key expires.

Denial reasons you will see (returned in Spanish):

`reason`	Situation
`Pulsera no encontrada`	That code matches no wristband
`Zona no permitida`	Their ticket does not grant access to that zone
`Fuera de fecha`	The wristband is not valid for the current day
`Pulsera blocked` / `lost`	Blocked or reported lost
`Pulsera en revisión — avisar a supervisor`	Unresolved double accreditation

Every call is recorded in the scan history, so the operation shows up in the organiser’s statistics attributed to your integration.

Reading the history

curl "https://api.ventry.es/v1/checkins?day=6a3d0512...&result=denied&limit=200" \
  -H "Authorization: Bearer $VENTRY_KEY"

{
  "object": "list",
  "data": [
    {
      "object": "checkin",
      "id": "6a3d0819a1e963300ee2cd44",
      "ticket_code": "TR-84213-092",
      "result": "denied",
      "denial_reason": "Entrada ya utilizada",
      "day": { "id": "6a3d0512...", "name": "Friday" },
      "device_id": "6a3d0620a1e963300ee2cb99",
      "occurred_at": "2026-06-12T19:42:11.004Z"
    }
  ],
  "has_more": false,
  "next_cursor": null
}

Reference implementation

const VENTRY = "https://api.ventry.es/v1";
const headers = {
  Authorization: `Bearer ${process.env.VENTRY_KEY}`,
  "Content-Type": "application/json",
};

/** Called by your door app. `scanId` is generated by the app when the QR is read. */
export async function accredit({ ticketCode, nfc, uhf, scanId }) {
  const response = await fetch(`${VENTRY}/tickets/${ticketCode}/check-in`, {
    method: "POST",
    headers: { ...headers, "Idempotency-Key": scanId },
    body: JSON.stringify({ wristband: { nfc, ...(uhf && { uhf }) } }),
  });

  if (response.ok) {
    return { ok: true, wristband: (await response.json()).wristband };
  }

  const { error } = await response.json();

  switch (error.code) {
    case "ticket_already_claimed":
      return { ok: false, escalate: true, message: "Already accredited. Call a supervisor." };
    case "wristband_in_use":
      return { ok: false, retryable: true, message: "Wristband in use. Take another." };
    case "ticket_not_found":
      return { ok: false, message: "Invalid ticket." };
    default:
      return { ok: false, message: error.message, requestId: error.request_id };
  }
}

export async function canEnterZone(nfc, zoneId) {
  const response = await fetch(`${VENTRY}/access-checks`, {
    method: "POST",
    headers,
    body: JSON.stringify({ wristband_code: nfc, zone: zoneId }),
  });

  // A failure here is an integration failure, not a denial: do not turn it into
  // "no entry" without distinguishing them, or an expired key will shut the door
  // on everyone.
  if (!response.ok) throw new Error("VENTRY unavailable");

  return response.json();
}

import os, requests

VENTRY = "https://api.ventry.es/v1"
HEADERS = {"Authorization": f"Bearer {os.environ['VENTRY_KEY']}"}

def accredit(ticket_code, nfc, scan_id, uhf=None):
    """Called by your door app. `scan_id` is generated when the QR is read."""
    wristband = {"nfc": nfc}
    if uhf:
        wristband["uhf"] = uhf

    response = requests.post(
        f"{VENTRY}/tickets/{ticket_code}/check-in",
        headers={**HEADERS, "Idempotency-Key": scan_id},
        json={"wristband": wristband},
        timeout=15,
    )

    if response.ok:
        return {"ok": True, "wristband": response.json()["wristband"]}

    error = response.json()["error"]

    if error["code"] == "ticket_already_claimed":
        return {"ok": False, "escalate": True,
                "message": "Already accredited. Call a supervisor."}
    if error["code"] == "wristband_in_use":
        return {"ok": False, "retryable": True,
                "message": "Wristband in use. Take another."}
    if error["code"] == "ticket_not_found":
        return {"ok": False, "message": "Invalid ticket."}

    return {"ok": False, "message": error["message"],
            "request_id": error["request_id"]}

def can_enter_zone(nfc, zone_id):
    response = requests.post(
        f"{VENTRY}/access-checks",
        headers=HEADERS,
        json={"wristband_code": nfc, "zone": zone_id},
        timeout=10,
    )

    # A failure here is an integration failure, not a denial: do not turn it into
    # "no entry" without distinguishing them, or an expired key will shut the
    # door on everyone.
    response.raise_for_status()

    return response.json()

<?php
const VENTRY = "https://api.ventry.es/v1";

/** Called by your door app. $scanId is generated when the QR is read. */
function accredit(string $ticketCode, string $nfc, string $scanId, ?string $uhf = null): array
{
    $wristband = ["nfc" => $nfc];
    if ($uhf !== null) {
        $wristband["uhf"] = $uhf;
    }

    try {
        // callVentry(): see the implementation on the Errors page.
        $result = callVentry("POST", "/tickets/$ticketCode/check-in", [
            "headers" => [
                "Idempotency-Key: $scanId",
                "Content-Type: application/json",
            ],
            "body" => json_encode(["wristband" => $wristband]),
        ]);

        return ["ok" => true, "wristband" => $result["wristband"]];
    } catch (VentryApiError $e) {
        return match ($e->code) {
            "ticket_already_claimed" => [
                "ok" => false,
                "escalate" => true,
                "message" => "Already accredited. Call a supervisor.",
            ],
            "wristband_in_use" => [
                "ok" => false,
                "retryable" => true,
                "message" => "Wristband in use. Take another.",
            ],
            "ticket_not_found" => ["ok" => false, "message" => "Invalid ticket."],
            default => [
                "ok" => false,
                "message" => $e->getMessage(),
                "request_id" => $e->requestId,
            ],
        };
    }
}

function canEnterZone(string $nfc, string $zoneId): array
{
    // A failure here is an integration failure, not a denial: do not turn it into
    // "no entry" without distinguishing them, or an expired key will shut the
    // door on everyone.
    return callVentry("POST", "/access-checks", [
        "headers" => ["Content-Type: application/json"],
        "body" => json_encode(["wristband_code" => $nfc, "zone" => $zoneId]),
    ]);
}

Get started

Core concepts

Use cases

Coming soon

Accreditation and access control

Accreditation

Zone control

Accreditation

Retries

What can go wrong

Zone control

Reading the history

Reference implementation

Accreditation

Zone control

​Accreditation

​Retries

​What can go wrong

​Zone control

​Reading the history

​Reference implementation

Accreditation

Retries

What can go wrong

Zone control

Reading the history

Reference implementation