Try it in one command

No Pi, no hardware, no configuration:

git clone https://github.com/ManasMadan/gatecrash
cd gatecrash
pnpm install && pnpm -r build
go run ./cmd/gatecrash-demo

It mints an organizer key, issues tickets, compiles a three-stage venue, boots a box, enrols scanners through the real QR ceremony, and walks tickets through the gates — then ends by proving one admission against a published Merkle root and tampering with it to show the proof fail.

Everything it does goes through the same code the box runs. It is also the end-to-end test CI runs on every pull request, which is deliberate: the demo cannot drift from the software without turning the build red.

What you will see

The interesting part is not the admissions. It is the refusals, because those are the decisions:

• ADMIT — through the north gate, with the tier colour and seat an usher acts on.
• ALREADY_USED — with which gate and how long ago. That evidence is what settles an argument at a door.
• WRONG_DOOR — a Block A ticket at Portal B, refused with a redirect to the right one.
• PREREQUISITE_MISSING — a pit wristband scanned before the outer gate. The venue is a graph, and this is what sequencing looks like at the door.
• EXPIRED_WINDOW — a screenshot of a rotating code, ninety seconds old.
• A retry — the same scan id resent, returning the original verdict rather than ALREADY_USED. Bad Wi-Fi must not turn somebody away.
• Counted passes — two drink tokens, then PASS_LIMIT_REACHED.
• Re-entry — out through the exit and back in, which is a different door from the one they came in by.

Keeping the box afterwards

go run ./cmd/gatecrash-demo -keep ./demo-data

Leaves the data directory behind, so you can start a box on it and poke at the real thing:

go run ./cmd/gatecrash serve --data ./demo-data

The boot log prints the dashboard URL with its token, the certificate fingerprint to compare when enrolling a scanner, and the addresses to open the apps at.

The simulator

The demo shows one event going right. The simulator runs thousands going wrong:

go run ./cmd/gatecrash-sim event -seeds 500
go run ./cmd/gatecrash-sim crowd -sweep

The first injects partitions, retries, reordering, clock skew and power cuts, then asserts the guarantees hold. The second is the mesh, across crowd density. See Correctness.