Developer runs real-time chat app for free using Cloudflare account sharding

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A solo developer built BatchUp, a real-time group chat app for a college community, in five days using a zero-cost infrastructure approach. The architecture relies on Cloudflare Durable Objects to isolate each conversation, preventing any single busy chat from degrading performance for others. To stay within free-tier limits, the system is distributed across eight Cloudflare accounts with seven shard workers, so no single account becomes a bottleneck. This isolate-then-shard pattern targets sub-100ms message delivery and is designed to scale without incurring hosting costs at current usage levels. The developer notes the approach suits other real-time use cases like multiplayer games or collaborative editing, but warns that managing cross-account routing and shard rebalancing adds meaningful architectural complexity.

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