Echo Vault

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  A community-built dungeon where today's contributions become tomorrow's challenges.

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  Leave Your Echo - Choose an encounter type and leave your Echo behind for future Reddit explorers.

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  Echo Sealed - Your contribution joins the shared Vault and becomes part of future adventures.

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  Enter the Vault - Face community-built encounters, make choices, survive five rooms, and earn points.

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  Victory - Survive the Echoes left by Reddit, complete the dungeon, and return for another run.

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  Your Echo's Reach - See how many explorers encountered your Echo and track its impact across community runs.

Inspiration

Reddit communities are built by their members, but most games treat players only as participants. We wanted to create an experience where the community itself builds the world that future players explore.

That idea became Echo Vault — a community-built dungeon where every Redditor can leave behind an "Echo" that becomes part of the adventure for future explorers.

What it does

Echo Vault turns a Reddit post into an evolving community dungeon.

Each user can contribute one Echo by choosing an encounter type such as a Trap, Monster, Treasure, or Blessing. Their contribution is added to the shared Vault, alongside seeded encounters that make every new dungeon immediately playable.

Players can then enter the Vault and explore a five-room run filled with encounters drawn from the community. Their decisions affect their HP and score as they try to survive until the end.

After contributing, users can also view Your Echo's Reach, an impact report showing how many explorers have encountered their contribution and how it has affected their journeys.

The result is a persistent multiplayer experience where one player's contribution becomes part of another player's adventure.

How we built it

Echo Vault was built using Devvit Web with React and TypeScript.

The frontend provides the contribution flow, dungeon gameplay, run results, and impact reports. The backend uses Devvit server APIs and Redis to maintain the shared community Vault.

Redis stores:

• Community-created encounters
• Seeded dungeon encounters
• One-contribution-per-user state
• Vault statistics and total runs
• Per-encounter impact statistics

New Echo Vault posts are automatically seeded with 10 encounters, allowing the dungeon to be playable immediately while still growing through community participation.

We also implemented validation for completed runs, authenticated API requests, duplicate seed protection, and persistent contribution tracking.

Challenges we ran into

One of our biggest challenges was implementing reliable persistence and community interaction while keeping the experience simple enough to play directly inside Reddit.

We also encountered an intermittent Devvit upload issue where valid authenticated uploads were occasionally rejected. After extensive debugging and repeated testing, we were able to successfully upload, install, test, and submit the final application for review.

Another challenge was ensuring that seeded encounters did not interfere with the one-contribution-per-user system. We solved this by keeping system-generated encounters separate from contributor identity records.

Accomplishments that we're proud of

We are proud that Echo Vault is not simply a game displayed on Reddit — the Reddit community actively becomes part of the game.

Every contribution permanently expands the Vault, and the impact system allows users to return later and see whether future explorers encountered their Echo.

We also built the complete experience end-to-end, including community contributions, persistent storage, procedural encounter selection, gameplay, run statistics, impact tracking, and a polished Reddit-native interface.

What we learned

Building Echo Vault taught us how to design a multiplayer experience around asynchronous community participation. We gained hands-on experience with Devvit Web, React, TypeScript, Redis-backed persistence, API validation, and deploying interactive experiences directly inside Reddit.

We also learned that designing for Reddit requires thinking beyond traditional multiplayer games. Players do not need to be online simultaneously to influence each other's experience.

What's next for Echo Vault

Future versions could introduce deeper strategic gameplay with inventory items, relics, branching dungeon paths, boss encounters, community leaderboards, and more detailed encounter creation.

The long-term vision is for every community to have a unique Vault shaped entirely by its members — where the choices made today become the challenges faced by tomorrow's explorers.

Built With

• devvit
• node.js
• react
• reddit
• redis
• tailwindcss
• typescript
• vite