We replaced Node.js with Bun for 5x throughput (trigger.dev)

Trigger.dev reports that it replaced Node.js with Bun for its Firestarter warm-start connection broker and saw about a 5x throughput increase. The team first removed a CPU-heavy SQLite-based metadata lookup, then switched to Bun’s native HTTP server APIs and trimmed hot-path overhead (notably Zod validation, header conversion, and debug logging). After deploying, they also found and fixed a Bun-specific memory leak tied to pending Promise<Response> not being resolved on client disconnects, which they corrected by resolving the request with an HTTP 499 status.