CapFilter

Inspiration It started with seeing the bald Reddit teddy with the antenna 🤔😂 and wondering how we could make its life—and the lives of real human moderators—a little easier. Managing high-volume subreddits often leads to moderator burnout due to repetitive tasks like filtering spam and tagging cross-platform reposts. I wanted to build a native, seamless solution that acts as an invisible assistant for mod teams.

What it does CapFilter is a mod-intelligence tool that automates post management, significantly reducing manual labor for subreddit moderators.

Cross-Platform Protection: Automatically detects and flags posts containing external links (Instagram, TikTok, Twitter, YouTube) to mitigate cross-platform spam.

Author Authority (Cap Elite): Prioritizes quality content by analyzing post titles for impact keywords and assigning appropriate flairs instantly.

Analytics Tracking: Utilizes Redis to track filtered content, providing moderators with a foundation for actionable moderation data.

How we built it The project was entirely built using TypeScript within VS Code, leveraging the pure Devvit Public API. Instead of relying on external web server wrappers, I focused on native Reddit integration. I utilized Devvit's addMenuItem for the user interface, the setPostFlair API for automated tagging, and configured Redis for state management and analytics.

Challenges we ran into The most significant hurdle was navigating the Devvit playtest environment and dealing with aggressive "ghost caching" in the UI. During the final build phase, the frontend menu button experienced rendering delays and latency on the test subreddits. However, this challenge forced a deep dive into the architecture, teaching me to trust backend terminal logs and ensuring the core logic was flawlessly executed even when the UI was out of sync.

Accomplishments that we're proud of I am incredibly proud of rapidly adapting to the Devvit native ecosystem in a very short time. Transitioning from standard app development to Reddit's specific component structure was a steep climb. Successfully compiling, debugging the architecture, and officially deploying Version 0.0.2 to the live Reddit Developer servers feels like a massive win.

What we learned This hackathon was a masterclass in platform-specific architecture. I learned the critical difference between wrapping an app in a web server versus writing "Pure Devvit" native code. I also learned a lot about Reddit's internal API mechanics, specifically how flairs and moderation states are programmatically altered using context triggers.

What's next for CapFilter The foundation is set. The next step is to introduce an Auto-Ban feature for severe cross-platform spam offenses and build a Configurable Dashboard where individual subreddits can define their own "High Impact" keywords and strictness levels.

Built With

• devvit-api
• npm
• redis
• typescript
• vscode