Show HN: Helix – AI-powered API mocking with strict schema enforcement https://ift.tt/Ej06ukA

Show HN: Helix – AI-powered API mocking with strict schema enforcement Helix is a dynamic mock server that generates data on the fly using LLMs (supports Ollama, DeepSeek, Groq). Key difference from other AI generators: Schema Enforcement. One of the biggest issues with LLMs is non-deterministic output. To solve this, Helix allows you to provide a "System Schema" (using TypeScript interfaces, JSON Schema, or plain text rules). The engine ensures the generated JSON strictly adheres to your defined keys and types, while still generating realistic values for the content. Features: - Local-First: Works completely offline with Ollama (Llama 3.2 is recommended). - Schema Safety: You can force strict structure compliance so your frontend doesn't break. - Chaos Mode: Optionally simulate latency and error rates. - Stack: Python 3.11, FastAPI, Redis, Docker. It's open source (AGPLv3). I'd love to hear your feedback, especially regarding the schema validation approach! Repo: https://ift.tt/nFemi5o https://ift.tt/nFemi5o December 19, 2025 at 05:28AM