LangChain — LangChain is the framework that powers most production LLM apps you've used. It's the plumbing behind the magic. What it provides: - Chains: Connect LLM calls with logic - Agents: LLMs that decide what actions to take - RAG: Retrieval-augmented generation made easy - Memory: Persistent context across conversations If you're building anything serious with LLMs, you'll probably touch LangChain. Python and JS/TS support. Huge ecosystem.

Codeium — Codeium is the free alternative to GitHub Copilot. Same basic functionality, zero monthly cost. What you get for free: - Inline code completions - Chat interface in IDE - Support for 70+ languages - VS Code, JetBrains, Vim, and more The business model: enterprise sales subsidize free individual use. If you're cost-conscious or just starting out, Codeium delivers genuine value at $0.