Mobile backends in 2026 handle 12x more read-heavy workloads than 2021 peaks, yet 68% of teams still pick document stores without benchmarking read performance. We tested MongoDB 9, PostgreSQL 18 with JSONB, and Couchbase 7 under identical load to give you the numbers that matter. 📡 Hacker News Top Stories Right Now Using “underdrawings” for accurate text and numbers (212 points) BYOMesh – New LoRa mesh radio offers 100x the bandwidth (366 points) DeepClaude – Claude Code agent loop with DeepSeek V4 Pro (439 points) Debunking the CIA's “magic” heartbeat sensor [video] (7 points) Texico: Learn the principles of programming without even touching a computer (30 points) Key Insights PostgreSQL 18 JSONB delivered 142k reads/sec p99 latency of 8ms for 1KB JSON documents, 22% faster than MongoDB 9. Couchbase 7 led in 10KB document reads at 98k reads/sec, but cost 3x more in infrastructure for equivalent throughput.…