Packages

Two npm packages, both unscoped and both MIT.

gatecrash-client

pnpm add gatecrash-client

The wire types and a thin client, with zero dependencies. Install this if you are writing anything that talks to a box: a turnstile controller, a till that sells at the door, a screen in the foyer, or your own scanner. The three shipped apps are built on it, so anything they can do, you can do.

The types — every request and response, including all fifteen verdicts and the venue plan.

A client — fetch, a deadline, and typed responses. Nothing else: no retry policy, no cache, no state machine, because at a gate those are decisions only the caller can make.

The QR codecs — GC1 static and GC2 rotating, encode and decode. The same code the wallet uses to generate a rotating code locally with no network.

The offline filter — a reader for the Bloom filter the box ships to scanners. This is what lets a gate tell "a ticket I cannot confirm right now" from "a QR somebody generated in a car park".

import { Client, newScanId, severityOf } from 'gatecrash-client'

const client = new Client({
  baseUrl: 'https://10.11.0.1:8443',
  token: deviceToken,
  timeoutMillis: 2_500, // a gate cannot wait longer than this
})

const result = await client.scan({
  scanId: newScanId(),
  payload: whateverTheCameraRead,
  checkpoint: 'gate-north',
})

if (severityOf(result.verdict) === 'admit') open()
else refuse(result.reason)

Generate your own scanId and reuse it on retry. Resend the same one and you get the original verdict rather than a spurious ALREADY_USED, which is the difference between a network blip and turning somebody away.

gatecrash-ui

pnpm add gatecrash-ui gatecrash-client react

The verdict screen and the venue map, as React components. They are a package rather than app internals because if you build your own scanner or wallet, these are the parts worth not rewriting — and the parts where the details took longest to get right.

<VerdictScreen result={result} onDismiss={clear} gateName="North Gate" />

// An attendee: their seat, their route, only the doors they can use.
<VenueMap plan={plan} seat={seat} route={route} openCheckpoints={next} focusSection="block-a" />

// The control room: every door named, occupancy shaded onto the zones.
<VenueMap plan={plan} showSeats={false} labelEveryGate occupancy={occupancy} />

Styles are three separate imports so you can take the components without the theme, and everything is driven by custom properties on :root:

import 'gatecrash-ui/tokens.css'
import 'gatecrash-ui/verdict.css'
import 'gatecrash-ui/map.css'

Versioning

Both are released together from the same repository, and breaking wire changes get a major version and a note in DECISIONS.md. The formats are versioned and the box refuses what it does not recognise, so a client built against an older release will not silently misread a newer box.

Not published

The three apps (scanner, attendee, dashboard) are private. They are embedded in the box binary and served from it, so there is nothing to install — and a separately versioned scanner that drifted from the box serving it is a problem nobody needs.