langchain-prod-checklist

# LangChain Production Checklist ## Overview Comprehensive go-live checklist for deploying LangChain applications to production. Covers configuration, resilience, observability, performance, security, testing, deployment, and cost management. ## 1. Configuration & Secrets - [ ] All API keys in secrets manager (not `.env` in production) - [ ] Environment-specific configs (dev/staging/prod) validated with Zod - [ ] Startup validation fails fast on missing config - [ ] `.env` files in `.gitignore` ```typescript // Startup validation import { z } from "zod"; const ProdConfig = z.object({ OPENAI_API_KEY: z.string().startsWith("sk-"), LANGSMITH_API_KEY: z.string().startsWith("lsv2_"), NODE_ENV: z.literal("production"), }); try { ProdConfig.parse(process.env); } catch (e) { console.error("Invalid production config:", e); process.exit(1); } ``` ## 2. Error Handling & Resilience - [ ] `maxRetries` configured on all models (3-5) - [ ] `timeout` set on all models (30-60s) - [ ] Fallback models configured with `.withFallbacks()` - [ ] Error responses return safe messages (no stack traces to users) ```typescript const model = new ChatOpenAI({ model: "gpt-4o-mini", maxRetries: 5, timeout: 30000, }).withFallbacks({ fallbacks: [new ChatAnthropic({ model: "claude-sonnet-4-20250514" })], }); ``` ## 3. Observability - [ ] LangSmith tracing enabled (`LANGSMITH_TRACING=true`) - [ ] `LANGCHAIN_CALLBACKS_BACKGROUND=true` (non-serverless only) - [ ] Structured logging...