Harper Best Practices

Guidelines for building scalable, secure, and performant applications on Harper. These practices cover everything from initial schema design to advanced deployment strategies.

When to Use

Reference these guidelines when:

• Defining or modifying database schemas
• Implementing or extending REST/WebSocket APIs
• Handling authentication and session management
• Working with custom resources and extensions
• Optimizing data storage and retrieval (Blobs, Vector Indexing)
• Deploying applications to Harper Fabric

How It Works

1. Review the requirements for the task (schema design, API needs, or infrastructure setup).
2. Consult the relevant category under "Rule Categories by Priority" to understand the impact of your decisions.
3. Apply specific rules from the "Quick Reference" section below by reading their detailed rule files.
4. If you're building a new table, prioritize the schema- rules.
5. If you're extending functionality, consult the logic- and api- rules.
6. Validate your implementation against the ops- rules before deployment.

Examples

See the concrete examples embedded in each rule subsection below (GraphQL schemas, REST query patterns, and deployment workflow snippets).

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Schema & Data Design	HIGH	schema-
2	API & Communication	HIGH	api-
3	Logic & Extension	MEDIUM	logic-
4	Infrastructure & Ops	MEDIUM	ops-

Quick Reference

1. Schema & Data Design (HIGH)

• adding-tables-with-schemas - Define tables using GraphQL schemas and directives
• schema-design-tooling - Core directives and GraphQL IDE/agent configuration
• defining-relationships - Link tables using the @relationship directive
• vector-indexing - Efficient similarity search with vector indexes
• using-blob-datatype - Store and retrieve large data (Blobs)
• handling-binary-data - Manage binary data like images or MP3s

2. API & Communication (HIGH)

• automatic-apis - Leverage automatically generated CRUD endpoints
• querying-rest-apis - Filters, sorting, and pagination in REST requests
• real-time-apps - WebSockets and Pub/Sub for Real-Time Apps
• checking-authentication - Secure apps with session-based identity verification

3. Logic & Extension (MEDIUM)

• custom-resources - Define custom REST endpoints using JS/TS
• extending-tables - Add custom logic to generated table resources
• programmatic-table-requests - Advanced filtering and sorting in code
• typescript-type-stripping - Use TypeScript without build tools
• caching - Implement and define caching for performance

4. Infrastructure & Ops (MEDIUM)

• deploying-to-harper-fabric - Scale globally with Harper Fabric
• creating-a-fabric-account-and-cluster - Setting up your Harper Fabric cloud infrastructure
• creating-harper-apps - Quickstart with npm create harper@latest
• serving-web-content - Ways to serve web content from Harper

How to Use

Read individual rule files for detailed explanations and code examples:

rules/adding-tables-with-schemas.md
rules/schema-design-tooling.md
rules/automatic-apis.md
rules/creating-harper-apps.md

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md