Spark (Meta AI, Open Source)

Meta's Spark is an open-source LLM released in May 2026 under a permissive commercial license, making it the most capable freely available model with performance matching GPT-5 class closed models on most benchmarks. Trained on Meta social media text and curated web data, it delivers exceptional conversational fluency and cultural awareness, and within 48 hours it was downloaded 4.2 million times on Hugging Face and fine-tuned for dozens of specialized use cases, including medical diagnosis assistance and legal document review by teams with no AI budget.