Fireworks AI's DevDay 2025, held in San Francisco, brought together leading AI minds and developers to explore advancements in open-source AI models and infrastructure. The event featured inspiring fireside sessions with industry leaders discussing real-world engineering challenges and solutions, such as optimizing model size and latency for user experiences and leveraging open-source models for niche tasks. Fireworks announced several new tools, including the Build Experiment Platform for seamless experimentation and the Build SDK for programmatic scaling and fine-tuning. Enhancements were made to supervised and reinforcement fine-tuning, multimodal model support, and voice agent capabilities, alongside the introduction of the Global Virtual Cloud for consistent GPU infrastructure across multiple regions. Fireworks also unveiled the 3-D Optimizer and support for NVIDIA B200s, emphasizing speed, quality, and cost efficiency. The event underscored Fireworks AI's commitment to providing flexible and robust infrastructure for AI development, with further workshops and model updates anticipated.