Humanloop is an LLM application development platform for engineering teams, combining prompt management, fine-tuning, evaluation, and monitoring into a unified workflow. Teams can systematically improve AI features using Humanloop's A/B testing, human review interfaces, and automated evaluation pipelines to measure model quality at every change. The platform integrates with any LLM API and provides a structured approach to managing the full lifecycle of AI features from experimentation to production monitoring, replacing ad-hoc prompt files with a proper engineering workflow.