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GDGC HACKATHON 2026

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48

Hours

2

Days

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10

Teams

THEME

BLACKOUT

At 3:47am on Tuesday, a solar flare hit Earth and took everything with it.

Not the lights. Not the internet. Those still work. What's gone is quieter than that and harder to explain.

The banking system suspended all transactions at 4:12am. Not because the servers failed — because the flare corrupted every digital record simultaneously. Accounts, balances, transaction histories. Gone. The physical infrastructure is intact. The information that gave it meaning is not.

By 6am, three major hospitals had locked their doors. Not because of damage. Because patient records, staff credentials, medication histories — all corrupted. A surgeon showed up for her shift and couldn't prove she was a surgeon. The hospital couldn't prove it either. They sent her home.

By noon, the courts had suspended all proceedings. Property records, legal documents, contracts, titles — unverifiable. A man showed up to work in a building he'd worked in for eleven years. Security turned him away. His access credentials no longer existed. Neither did proof that they ever had.

London population: 9,000,000
Hours since flare: 14
Digital records recovered: 0%
Estimated time before momentum fails: unknown

The city is physically intact. The roads work. The shops are open. But the invisible systems that told us who owned what, who owed whom, who was authorised to do what — those are gone.

We are fourteen hours in. Nobody knows how long this lasts. Nobody knows if the records can be recovered. Nobody knows what happens if they can't. What we know is this: the city is still running on momentum. People are still going to work out of habit. Shops are still opening because nobody has told them not to. The tube is still running because the drivers showed up.

But momentum runs out.

Somewhere in the next 28 hours, the questions that nobody has answered yet are going to start mattering. Who owns what. Who has the right to do what. Who gets to decide. How do you prove anything about yourself to a stranger when every record that confirmed it no longer exists.

Nine million people. Twenty eight hours. No instructions. What do you build?

Hackathon 2026

PROJECTS

Proofline cover

Team 1

Proofline

A local-first identity vault for proving credentials after outages.

Next.jsTypeScriptWeb CryptoIndexedDB
View project
CivicQueue cover

Team 2

CivicQueue

A queue and triage system for city services during record failure.

ReactNode.jsPostgresTailwind CSS
View project
StreetLedger cover

Team 3

StreetLedger

A temporary transaction ledger for shops operating without banks.

SvelteSQLitePWAQR Codes
View project
MedRecall cover

Team 4

MedRecall

A paper-to-digital medical intake tool for emergency wards.

Next.jsFHIRPrismaZod
View project
NeedNet cover

Team 5

NeedNet

A trust map for matching volunteers to verified local needs.

MapboxSupabaseReactEdge Functions
View project
RecordWeave cover

Team 6

RecordWeave

A crowdsourced reconstruction tool for corrupted public records.

PythonOCRFastAPIPostgres
View project
RouteSignal cover

Team 7

RouteSignal

A lightweight dispatch board for transport when credentials fail.

VueRedisWebSocketsPWA
View project
ClaimKit cover

Team 8

ClaimKit

A dispute-resolution assistant for ownership and access claims.

RemixDrizzleSQLiteCloudflare
View project
SignalBoard cover

Team 9

SignalBoard

A public broadcast composer for clear emergency instructions.

AstroContentfulTypeScripti18n
View project
MomentumOps cover

Team 10

MomentumOps

A continuity planner for workplaces running on habit.

Next.jsNeonClerkTailwind CSS
View project

THANK YOU