How OpenAI Function Calling Turns LLMs into Real-World Systems Most AI applications fail after the demo. Not because the model isn’t powerful but because it isn’t connected to real systems. In 2025, building useful AI means going beyond prompts and giving LLMs the ability to fetch live data, validate inputs, and trigger real actions. That’s exactly what OpenAI Function Calling enables. I’ve put together a practical guide showing how developers can connect LLMs to reliable, free APIs turning chatbots into data-driven, production-ready systems. 👉 Read the full guide here: 🔗 https://blog.apilayer.com/openai-function-calling-how-to-connect-llms-to-the-best-free-apis-2025/ Inside the guide: • How function calling works in real applications • How to design clean schemas for structured outputs • How to integrate APIs for currency, weather, news, validation, and more • Why free-tier APIs are powerful for MVPs and internal tools • Practical patterns you can reuse across projects If you’re building AI assistants, automation tools, or developer platforms, this approach isn’t optional anymore it’s becoming the standard. Would love to hear how others are using function calling in production 👇 #AIEngineering #OpenAI #APIs #FunctionCalling #LLMs #SoftwareArchitecture #AIDevelopment #DevTools #TechLeadership