A deep dive into building a production-grade Rust API server with multi-tier scheduling, HMAC auth, Lemon Squeezy webhooks, and 9 platform adapters — the engine behind DotSuite. Most of my tools in the DotSuite ecosystem — VS Code extensions, CLI tools, Telegram bots — were islands. Each one doing its own thing. No shared auth. No shared billing. No shared scheduling. That changed when I started building DotShare v3 , a VS Code extension that publishes code snippets to 9 platforms simultaneously. The moment I needed scheduling, quotas, and payments, one thing became clear: I need a real backend. This article is about dotsuite-core — a private Rust server that is the beating heart of the DotSuite ecosystem. I won't open source it, but I'll walk you through the architecture, the decisions, and enough real code that you can build your own version. Why Rust? Not because it's trendy. Three very specific requirements drove the choice: 1. Exact-second scheduling.…