VidaiMock is a tiny, lightning-fast simulator that lets you test your AI apps without the expensive API bills. It emulates OpenAI, Anthropic, Gemini, and more with zero configuration. Built in Rust for maximum speed! ✅ Physics-Accurate Simulation: Emulates real-world wire protocols (Streaming) and token delivery timing. (Chaos testing) ✅ Truly Dynamic ✅ Instant-On, Zero Fixtures: A single ~7MB binary ✅ Deeply Extensible: Use Tera (Jinja2) templates to mock any proprietary or internal LLM API

Hey Product Hunt! 👋 I’m part of the team at Vidai, and we’re coming to you from rainy (but lovely!) Scotland 🏴󠁧󠁢󠁳󠁣󠁴󠁿. If you’ve ever built an AI-powered app, you know the "Testing Tax". You spend half your time waiting for API responses and the other half watching your credit balance drop just to fix a tiny UI bug. 💸 We got tired of it, so we built VidaiMock. It’s a single, tiny file (~7MB!) that lives on your computer and pretends to be OpenAI, Anthropic, or Gemini. It doesn't just send back static text—it actually mimics how "real" AI feels, including that token-by-token streaming effect we all love (and our code often breaks on!). Why you'll love it: Zero Config: Download it, run it, and it works instantly. No Docker, no databases, no fuss. Save Money: Test your app all day long for exactly $0.00. Test the "Scary Stuff": Ever wonder how your app handles a super slow connection or a random crash? You can simulate that in one click. Privacy First: Everything stays local. No data leaves your machine. We built this to help us build our own enterprise tool, Vidai.Server (our high-density enterprise gateway). We realized that we spent so much time building the "simulator" for our own dev work that it felt wrong not to share it with everyone else. We’re open-source (Apache 2.0) and would love to hear what you think. Grab the binary, give it a whirl, and let us know: what’s the most annoying thing about building with LLMs right now? Sláinte, The Vidai Team 🏴󠁧󠁢󠁳󠁣󠁴󠁿

VidaiMock feels like a very practical tool for anyone creating video content who wants quick, realistic mockups without manual editing. Helping creators turn raw clips into polished previews or portfolios could save a lot of time and spark more confident sharing. Congrats on launching this on Product Hunt!

VidaiMock

Open Source LLM Native Mock API Test Engine

Open Source LLM Native Mock API Test Engine