Harper.Fast

Harper is an open-source Node.js performance platform that fuses database, cache, application hosting, and messaging into one in-memory process. Instead of wiring together separate services for your database, API layer, caching, and real-time messaging, Harper runs everything in a single runtime with shared memory, delivering microsecond-level data access and eliminating the latency, complexity, and configuration overhead of multi-service architectures.

Define your data schema in GraphQL and Harper instantly generates full REST APIs, no controllers, no routes, no ORM. Extend with custom JavaScript resources for application logic. Built-in real-time messaging supports WebSockets, MQTT, and Server-Sent Events without external brokers.

Deploy globally with Harper Fabric, which distributes workloads across multiple nodes by selecting your regions and latency targets. Scaffold a new project in seconds with npm create harper@latest

Harper is used in production by enterprise organizations including Fortune 500 retailers, delivering sub-millisecond response times at scale. It is particularly well-suited for AI-assisted development and agentic engineering, since the entire application definition fits in a few declarative files rather than dozens of infrastructure configurations.

Open source under the Apache 2.0 license. Free tier available with no credit card required.