# I would like to start with... {% hint style="info" %} If you are brand new to the platform, first skim [Development](https://docs.rierino.com/quick-start/development) and [Training Examples](https://docs.rierino.com/examples/training-examples). They give you the basic mental model fast. {% endhint %} ## A CRUD service **Typical use cases** * You need a backend for a front-end or admin tool. * You want standard create, read, update, and delete endpoints. * You want to expose a collection or table quickly. This is the fastest path in Rierino. In most cases, you only need to drag & drop an element to an existing runner and click on save. **Start here** * [Exercise: Create a CRUD Service](https://docs.rierino.com/examples/training-examples/exercise-create-a-crud-service) * [Video: Build full CRUD under 60 seconds](https://www.youtube.com/watch?v=iW_klLfvJuk) **Learn next** * [State Managers](https://docs.rierino.com/devops/microservices/elements/state-managers) for storage patterns * [Runners](https://docs.rierino.com/devops/microservices/runners) for selecting microservices for your services * [Gateway Channels](https://docs.rierino.com/devops/gateway-and-security/gateway-servers/gateway-channels) for granular control on RBAC ## An API endpoint **Typical use cases** * You need more than standard CRUD behavior. * You want a custom request/response contract. * You need validation, transformation, aggregation, or branching. * You want an API-first architecture. In Rierino, custom APIs usually start as **Sagas**. A saga is a flow. It can call handlers, states, queries, and other services. **Start here** * [Exercise: Create an API Endpoint](https://docs.rierino.com/examples/training-examples/exercise-create-an-api-endpoint) **Most common flow steps** * [Read Data](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/core-actions/read-data) * [Write Data](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/core-actions/write-data) * [Query Data](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/core-actions/query-data) * [Transform Step](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/transform-step) * [Condition Step](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/condition-step) **Learn next** * [API Flows](https://docs.rierino.com/devops/api-flows) for details on how to build Sagas * [Handlers](https://docs.rierino.com/devops/microservices/elements/handlers) for rich set of actions available in steps ## Multi-systems integration or orchestration **Typical use cases** * You need to call third-party APIs. * You need to combine multiple internal services. * You need fan-out, batching, retries, or transformations. * You want middleware or ESB-like behavior. This path is also saga-first. The difference is that the saga coordinates **multiple systems**, not just one endpoint. **Start here** * [Call Rest API](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/core-actions/call-rest-api) * [Video: Integrate External APIs in 2 Minutes](https://www.youtube.com/watch?v=4KXbjt1qylk) **Learn next** * [API Based Systems](https://docs.rierino.com/devops/microservices/elements/systems/api-based-systems) * [Call SOAP API](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/specialized-actions/call-soap-api) ## An internal application **Typical use cases** * You need an admin tool or back-office UI. * You want forms, lists, editors, and actions without custom front-end code. * You want internal users to manage data or trigger flows. **Start here** * [Exercise: Create a UI Screen](https://docs.rierino.com/examples/training-examples/exercise-create-a-ui-screen) * [Video: Build a Functional UI in 2 Minutes](https://www.youtube.com/watch?v=qWVzLsIXTmA\&t=26s) **Learn next** * [Apps](https://docs.rierino.com/design/user-interface/apps) for grouping UIs into applications * [UIs](https://docs.rierino.com/design/user-interface/uis) for creating data entry and workflow forms * [API Mapping](https://docs.rierino.com/design/api-mapping) for mapping backend to frontend * [Data Schema](https://docs.rierino.com/design/data-schema) for structuring your data model * [Orchestrate User Task](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/core-actions/orchestrate-user-task) for business process flows ## An AI agent **Typical use cases** * You want a conversational interface on top of your services. * You want an agent that can call tools, not just chat. * You want to expose capabilities as agent APIs, MCP, or A2A. Rierino agents are usually built from: * a governed **GenAI model** * one or more **tool sagas** or **tool states** * optional **interfaces** for richer responses **Start here** * [AI Agent Example](https://docs.rierino.com/examples/training-examples/ai-agent-example) * [Video: Build Actionable AI Agents in 2 Minutes](https://www.youtube.com/watch?v=jgKj4_019Ps) * [GenAI Models](https://docs.rierino.com/data-science/genai-models) **Learn next** * [AI Agent APIs](https://docs.rierino.com/data-science/genai-models/ai-agent-apis) * [Service MCP Requests](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/ml-and-ai-actions/service-mcp-requests) * [Service A2A Requests](https://docs.rierino.com/devops/api-flows/configuring-saga-steps/event-step/ml-and-ai-actions/service-a2a-requests) ## If you are not sure which path fits Use this quick rule: * Need standard data APIs fast → start with **CRUD service** * Need custom business endpoints → start with **API endpoint** * Need multi-system coordination → start with **integration or orchestration flow** * Need an internal screen → start with **internal application** * Need conversational automation → start with **AI agent** If you want one guided path that touches most core concepts, start with the [In-depth Exercise](https://docs.rierino.com/examples/in-depth-exercise).