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.

Continue — Continue is the open-source alternative to Copilot and Cursor. Full control, any model, no vendor lock-in. Key differentiators: - Use any LLM: Claude, GPT-4, Llama, Ollama, etc. - VS Code and JetBrains extensions - Custom slash commands and context providers - Self-host or use their cloud For teams that need flexibility or can't send code to third parties, Continue is the answer. Apache 2.0 licensed.