# Kopra

> Custom fields as a service. Add custom fields to your SaaS with a TypeScript SDK, REST API, and MCP server for AI agents.

## Integration Resources

- [LLM Integration Guide (plain text)](https://kopra.dev/api/llm-context) - complete walkthrough with code examples
- [OpenAPI Spec (JSON)](https://kopra.dev/api/docs.json) - machine-readable, all 26 endpoints
- [Interactive API Docs](https://kopra.dev/api/docs) - Scalar-powered, with Try It console
- [TypeScript SDK](https://www.npmjs.com/package/@kopra-dev/sdk) - npm install @kopra-dev/sdk
- [MCP Server](https://www.npmjs.com/package/@kopra-dev/mcp) - 16 tools for AI agents

## Technical Articles

- [Building Workflows on Custom Field Data with Webhooks and REST API](https://kopra.dev/blog/workflows-with-kopra-webhooks-api) - webhook events, automation, Make/n8n/Zapier integration
- [Adding Custom Fields to an Express + React App](https://kopra.dev/blog/integration-walkthrough-express-react) - end-to-end integration walkthrough
- [Custom Fields for Booking and Healthcare Applications](https://kopra.dev/blog/custom-fields-for-booking-healthcare) - intake forms, insurance fields, compliance patterns
- [How Kopra Secures Your Customer Data](https://kopra.dev/blog/kopra-security-architecture) - multi-tenant isolation, JWT scoping, HMAC signatures
- [Add Custom Fields to Your React App in 5 Minutes](https://kopra.dev/blog/add-custom-fields-react-app) - step-by-step SDK integration tutorial
- [Custom Fields for Project Management Tools](https://kopra.dev/blog/custom-fields-for-project-management) - PM-specific patterns and examples
- [Custom Fields for CRM Applications](https://kopra.dev/blog/custom-fields-for-crm) - CRM-specific patterns and examples
- [Build vs Buy: Custom Fields for Your SaaS Product](https://kopra.dev/blog/build-vs-buy-custom-fields) - cost comparison with data tables
- [Custom Fields in Multi-Tenant SaaS: Architecture Guide](https://kopra.dev/blog/multi-tenant-custom-fields-architecture) - deep technical architecture comparison
- [How to Build a Custom Fields System for Your SaaS](https://kopra.dev/blog/how-to-build-custom-fields) - database patterns (EAV, JSONB, extension tables), validation, multi-tenancy
- [Why Every SaaS Eventually Needs Custom Fields](https://kopra.dev/blog/why-every-saas-needs-custom-fields) - business case with industry examples

## Key Facts

- No direct competitor in the "custom fields as a service" space
- 9 field types: string, number, boolean, date, select, multiselect, email, url, textarea
- Token model: one token per tenant, works for any field group or entity
- Free tier: 2 field groups, 3 tenants, 1K API calls/month
- Rate limits: 1,000 API requests per 15 minutes, 50 token requests per 15 minutes
- Multi-tenant: data isolated by clientId, validated on every request
- Webhooks: events for all field and value changes, cryptographically signed, automatic retries