A pull request sits open for four days because the backend change can't be reviewed without running it. Someone spins up a staging server manually. Someone else opens an ngrok tunnel from their laptop and forgets to close it. The client asks for a link and gets a screenshot instead. We've been that engineer. We built PreviewDrop to stop being that engineer. The core promise is simple: push a feature branch, get a live HTTPS URL posted to the pull request as a commit status check. The container runs, serves traffic, self-destructs when your TTL expires. No staging server to maintain. No ngrok tunnel to keep alive. But the "simple" part took some doing. Here's the architecture that makes it work. Why Most Preview Tools Don't Work for Backend Stacks Vercel preview deployments are excellent — for Next.js. Render's PR previews work for web services that fit their build pipeline. But backend stacks are different. Django, Rails, Laravel, FastAPI, Spring Boot — these are long-lived processes in containers.…