Inspiration
Reddit moderation currently operates in silos. If a coordinated harassment ring, spam bot network, or ban evasion cluster hits r/gaming, the moderators there will ban them. However, hours later, those same bad actors will hit r/learnprogramming or r/AskReddit using slightly mutated text (like using lookalike Unicode characters) and new accounts.
Because communities don't share real-time defense intelligence, they are forced to fight the same battles independently. We were inspired to build HiveMind to create a platform-wide "collective immune system" where an attack on one community automatically immunizes all other participating subreddits.
What it does
HiveMind links participating subreddits into a zero-knowledge threat-intelligence grid:
- Semantic Mutation Tracking: Instead of relying on easily-bypassed keyword filters, HiveMind uses Gemini AI to extract the abstract behavioral DNA of a violation (rhetorical pattern, coordination frequency, behavioral cadence).
- Behavioral Vaccine Generation: Once a mod flags a violation, HiveMind compiles this semantic fingerprint into a lightweight, encrypted mathematical hash token—a "behavioral vaccine."
- Global Swarm Push: The vaccine token is instantly broadcast to all participating subreddits using a high-speed centralized Redis cluster.
- Predictive Pre-Emptive Shielding: When the attacker lands on another community in the network, the system recognizes their behavioral fingerprint and pre-emptively quarantines them before their first toxic post can go live.
How we built it
- Frontend: Built with React 19, TypeScript, and Lucide React, styled with a sleek dark-mode glassmorphic interface.
- Backend: Built using the Hono framework and hosted natively on the Reddit Devvit platform.
- Real-Time Synchronization: Powered by a Redis data layer for lightning-fast pub/sub vaccine distribution.
- AI Intelligence: Integrated server-side Gemini API endpoints to dynamically analyze text patterns and generate moderation action roadmaps.
Challenges we ran into
The biggest challenge was maintaining zero-knowledge privacy. We could not simply broadcast usernames, IP addresses, or raw violation text across communities, as that would violate user privacy and trust. We solved this by compiling the semantic patterns and metadata into an encrypted mathematical hash token (the vaccine) which contains no personally identifiable information (PII) but uniquely identifies the behavioral signature of the attack.
Accomplishments that we're proud of
- Successfully creating a fully compiled, working Reddit App on the Devvit platform.
- Building a modular, reactive interface that separates active violation streams, historic violations, and the global Swarm network view.
- Keeping the entire codebase compile-ready and completely free of typescript or linting errors.
What we learned
We learned that collective swarm intelligence is exponentially more effective at stopping malicious coordination than individual regex-based AutoMod rules. By sharing defense signatures, we can turn Reddit into an environment hostile to organized bot nets and harassment rings.
Built With
- devvit
- gemini
- hono
- react
- redis
- tailwind-css
- typescript
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