Brigade Watch

Inspiration

Moderators often notice brigades only after a thread has already become chaotic: comments arrive faster than the team can read them, unfamiliar accounts appear at once, and manual cleanup begins too late. Brigade & Raid Early Warning System was built to give moderators an earlier signal and a faster response path directly inside Reddit.

What it does

The app monitors new posts and comments in a subreddit and records recent activity in Devvit Redis. It evaluates three signals: sudden thread velocity spikes, influxes of young accounts, and surges of accounts with no prior history in the subreddit.

When suspicious activity is detected, the app creates a moderator alert and sends a modmail notification. The alert shows the fired signals, severity, affected thread, account-age histogram, suspicious accounts, and timestamp. Moderators can activate a temporary lockdown for 1 hour, 6 hours, or 24 hours. During lockdown, posts or comments from very young or low-karma accounts are automatically removed with a clear explanation.

The app also includes a dashboard showing recent alerts, lockdowns, removals, high-velocity threads, and estimated moderator time saved.

How we built it

We built the app on Reddit Devvit using TypeScript and @devvit/public-api. Devvit triggers listen for new post and comment events, and Devvit Redis stores rolling activity windows, per-user subreddit history, alert cooldowns, lockdown state, and dashboard metrics.

The detection logic runs after incoming events and combines multiple signals into medium or high severity alerts. The dashboard and alert surfaces are Devvit custom posts, while lockdown controls use Devvit forms and Reddit API moderation actions.

For demo and judging, we added a safe synthetic demo flow that generates brigade-like activity without needing real users or external infrastructure.

Challenges we ran into

Devvit is a fast-moving platform, so we had to verify APIs carefully and adapt to current behavior. One challenge was making custom post forms work correctly; the alert lockdown form needed Devvit’s useForm hook instead of a global form helper.

Another challenge was making demo mode reliable for recording. Scheduled jobs can be hard to demonstrate live, so we added a deterministic Start Demo button that generates a realistic alert while tagging synthetic data so it does not pollute real dashboard stats.

Accomplishments that we're proud of

We are proud that Brigade Watch runs entirely inside Reddit with no external server, database, or hosting. The app connects detection, alerting, modmail, dashboard metrics, and response controls into one moderator workflow.

We are also proud of the practical demo mode. It lets reviewers and moderators see the full incident flow safely: dashboard, alert, modmail, lockdown activation, and early deactivation.

What we learned

We learned how to build a full Devvit moderation workflow with triggers, Redis, custom posts, forms, scheduled jobs, and Reddit API moderation actions. We also learned that moderation tools need to be conservative, explainable, and easy to operate during stressful moments.

Most importantly, we learned that the best mod tooling is not just detection. It also needs to help moderators understand what happened and take a reversible action quickly.

What's next for Brigade & Raid Early Warning System

Next, we would add deeper subreddit baselining, richer false-positive controls, and clearer post-level drilldowns for moderators. We would also add more configurable alert destinations and improve response-time measurement so teams can evaluate how quickly incidents are handled.

After hackathon submission, the focus would be testing with real moderation teams, tuning thresholds for communities of different sizes, and preparing the app for broader App Directory use once Reddit review is complete.

Built With

• api
• custom
• devvit
• posts
• reddit
• redis
• scheduler
• triggers
• typescript