LangChain Multi-Environment Setup

Overview

Configure LangChain across development, staging, and production environments with isolated API keys, environment-specific settings, and proper secret management. Each environment gets its own credentials and configuration to prevent cross-environment data leakage.

Prerequisites

• Separate LangChain API keys per environment

• Secret management solution (environment variables, Vault, or cloud secrets)

• CI/CD pipeline with environment-aware deployment

• Application with environment detection logic

Environment Strategy

Environment Purpose API Key Source Settings

Development Local development .env.local

Debug enabled, relaxed limits

Staging Pre-production testing CI/CD secrets Production-like settings

Production Live traffic Secret manager Optimized, hardened

Instructions

Step 1: Configuration Structure

config/ langchain/ base.ts # Shared defaults development.ts # Dev overrides staging.ts # Staging overrides production.ts # Prod overrides index.ts # Environment resolver

Step 2: Base Configuration

// config/langchain/base.ts export const baseConfig = { timeout: 30000, # 30000: 30 seconds in ms maxRetries: 3, cache: { enabled: true, ttlSeconds: 300, # 300: timeout: 5 minutes }, };

Step 3: Environment-Specific Configs

// config/langchain/development.ts import { baseConfig } from "./base";

export const developmentConfig = { ...baseConfig, apiKey: process.env.OPENAI_API_KEY_DEV, debug: true, cache: { enabled: false, ttlSeconds: 60 }, };

// config/langchain/staging.ts import { baseConfig } from "./base";

export const stagingConfig = { ...baseConfig, apiKey: process.env.OPENAI_API_KEY_STAGING, debug: false, };

// config/langchain/production.ts import { baseConfig } from "./base";

export const productionConfig = { ...baseConfig, apiKey: process.env.OPENAI_API_KEY_PROD, debug: false, timeout: 60000, # 60000: 1 minute in ms maxRetries: 5, cache: { enabled: true, ttlSeconds: 600 }, # 600: timeout: 10 minutes };

Step 4: Environment Resolver

// config/langchain/index.ts import { developmentConfig } from "./development"; import { stagingConfig } from "./staging"; import { productionConfig } from "./production";

type Environment = "development" | "staging" | "production";

const configs = { development: developmentConfig, staging: stagingConfig, production: productionConfig, };

export function detectEnvironment(): Environment { const env = process.env.NODE_ENV || "development"; if (env === "production") return "production"; if (env === "staging" || process.env.VERCEL_ENV === "preview") return "staging"; return "development"; }

export function getLangChainConfig() { const env = detectEnvironment(); const config = configs[env];

if (!config.apiKey) { throw new Error(OPENAI_API_KEY not set for environment: ${env}); }

return { ...config, environment: env }; }

Step 5: Secret Management

Local development (.env.local - git-ignored)

OPENAI_API_KEY_DEV=your-dev-key

GitHub Actions

Settings > Environments > staging/production > Secrets

Add OPENAI_API_KEY_STAGING and OPENAI_API_KEY_PROD

AWS Secrets Manager

aws secretsmanager create-secret
--name langchain/production/api-key
--secret-string "your-prod-key"

GCP Secret Manager

echo -n "your-prod-key" | gcloud secrets create langchain-api-key-prod --data-file=-

.github/workflows/deploy.yml

jobs: deploy-staging: environment: staging env: OPENAI_API_KEY_STAGING: ${{ secrets.OPENAI_API_KEY_STAGING }}

deploy-production: environment: production env: OPENAI_API_KEY_PROD: ${{ secrets.OPENAI_API_KEY_PROD }}

Error Handling

Issue Cause Solution

Wrong environment Missing NODE_ENV Set environment variable in deployment

Secret not found Wrong secret path Verify secret manager configuration

Cross-env data leak Shared API key Use separate keys per environment

Config validation fail Missing field Add startup validation with Zod schema

Examples

Quick Environment Check

const config = getLangChainConfig(); console.log(Running in ${config.environment}); console.log(Cache enabled: ${config.cache.enabled});

Startup Validation

import { z } from "zod";

const configSchema = z.object({ apiKey: z.string().min(1, "OPENAI_API_KEY is required"), environment: z.enum(["development", "staging", "production"]), timeout: z.number().positive(), });

const config = configSchema.parse(getLangChainConfig());

Resources

• LangChain Configuration

• LangSmith Environments

Next Steps

For deployment, see langchain-deploy-integration .

Output

• Configuration files or code changes applied to the project

• Validation report confirming correct implementation

• Summary of changes made and their rationale