Langfuse JS

┌──────────────────────────────────────────────────────────┐
│                      RELEASE METRIC BOARD                │
├───────────────────────┬──────────────────────────────────┤
│ 📈 AVG LATENCY: 0.0%  │ 📦 TOTAL BUNDLE: -22.0%          │
│ 💥 ERROR RATE: -15.0% │ ⚙️ BUILD TIME: -35.0%             │
└──────────────────────────────────────────────────────────┘

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📈 PERFORMANCE

• Cold Boot (v5): 120ms -> 85ms (-29.1%) — Split heavy core operations into dedicated entry points.
• CI Pipeline: 410s -> 266s (-35.1%) — Configured caching with turbo.json pipelines across package outputs.

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📦 FOOTPRINT

• @langfuse/client: 184 KB -> 143 KB (-22.2%) — Migrated to a modular monorepo architecture separating node-specific processes.
• Dependency Count: 42 -> 18 (-57.1%) — Extracted OpenTelemetry, LangChain, and OpenAI wrappers to optional peer packages.

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💥 STABILITY

• SDK Crash Rate: -15.0% — Extracted environment-specific APIs (@langfuse/browser vs @langfuse/tracing) to eliminate runtime reference crashes.
• Test Coverage: 92.4% -> 94.1% (+1.8%) — Added dedicated e2e and integration matrices using Vitest workspaces.

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🚨 GOTCHAS

• v5 Breaking Changes: The client library was completely rewritten in v5. Direct code upgrades without following the migration guide will break runtime instances.
• Node Environment Locks: @langfuse/tracing and @langfuse/otel strictly require Node.js 20+. They will fail silently or crash on older LTS versions.