Harper

Harper is an open-source Node.js unified development platform that fuses database, cache, application, and messaging layers into one in-memory process. With Harper you can build ultra-high-performance services without boilerplate code and scale them horizontally.

Key Features:

Unified Runtime: Database, cache, application logic, and messaging all operate within a single in-memory Node.js process, eliminating external dependencies and reducing latency.

In-Memory Performance: Data and compute share memory space for microsecond-level access times and exceptional throughput under load.

Native Messaging: Built-in publish/subscribe messaging with Websockets and MQTT enables real-time communication between nodes and clients without external brokers.

Developer Simplicity: Annotate your data schema with @export to instantly generate REST APIs. Extend functionality by defining custom endpoints in JavaScript.

Deploy with Harper Fabric for Horizontal Scalability: Distribute workloads across multiple Harper nodes by selecting your regions and latency targets.

Quick Installation

npm i -g harper

Get started building Harper applications by following our Learn guide: https://docs.harperdb.io/learn

Contributing to Harper

Harper's open source core accepts contributions from the community! Please read our guidelines before contributing.

Open an issue if you find a bug, or reach out on our Discord if you have questions or want to discuss ideas.

For more information on how to contribute, please see our:

• Contributing Guide
• Code of Conduct
• Support

Harper Pro

Harper Pro is the source-available distribution of Harper, built on top of this open source harper core. It extends the core with enterprise features including multi-node replication, certificate management, and extended profiling and analytics. It is licensed under the Elastic License 2.0.

What is HarperDB?

HarperDB is our previous name. Earlier in 2025, we rebranded to just "Harper" to reflect our evolution from a database to a full performance platform. The core technology remains the same, but we've expanded our vision to encompass more than just database functionality. Since this repo was created from the existing Harper codebase, you may still see references to the old name "HarperDB" in certain places.

Security

Please review our Security Policy for reporting vulnerabilities.

Please always disclose vulnerabilities privately to [email protected] before making them public.

License

Harper is available under the Apache-2.0 License. See the LICENSE for the full license text or the License FAQ for more information.