# Developers

> Choose API integration or extension development to connect FastGPT and build plugins, model presets, and Skills.

Source: https://doc.fastgpt.io/en/developers

## Choose a development task

* [API integration](/en/openapi/intro): Make your first request, then integrate Apps, conversations, and Datasets.
* [Plugin system](#plugin-system): Build system tool plugins, contribute model presets, and package them for FastGPT.

## Developer Integration Architecture

FastGPT provides an open capability matrix for enterprise systems and developers:

![Integrate through a trusted backend](https://cdn.jsdelivr.net/gh/labring/fastgpt-img@main/diagrams/integration-overview.en.light.svg)

Keep API keys on a trusted server. Identity proxy is optional and requires endpoint support and a trusted mapping to a member in the same team. MCP clients use the separately configured MCP service and its authentication.

## Credential Types and Authentication

Each endpoint declares the credentials it accepts. Check the authentication method for each endpoint in `/apidoc/systemopenapi` or `/apidoc/devapi` before integrating.

| Credential             | Transport Location                       | Permission Scope                                                                  | Recommended Scenario                                     |
| ---------------------- | ---------------------------------------- | --------------------------------------------------------------------------------- | -------------------------------------------------------- |
| **Team API Key**       | `Authorization: Bearer <apiKey>`         | Scoped to resources available to the issuing team member                          | Backend integrations, automated jobs, model calls        |
| **User Session Token** | Cookie `fastgpt_token` or `token` header | Current member permissions, subject to endpoint authorization and session checks  | Web UI communication, same-origin management APIs        |
| **Root Key**           | Header `rootkey: <ROOT_KEY>`             | Administrative operations on endpoints that explicitly enable root authentication | Cross-team maintenance, model status probing, migrations |

## Core Integration Workflows

1. [API Quick Start](/en/openapi/intro): Obtain team API keys, execute the first end-to-end request, and connect via the official OpenAI SDK.
2. [Identity Proxy](/en/openapi/identity-proxy): Execute on behalf of end users using `authProxy` to enforce member-level permissions and audit logging.
3. [Application and Workflow Integration](/en/openapi/app): Execute published Chat Agents, Agent V2, and Workflows while injecting global variables.
4. [Conversations and 18 SSE Stream Events](/en/openapi/chat): Maintain persistent `chatId` sessions and parse answer chunks, thoughts, node statuses, plans, and interactive pauses.
5. [Knowledge Base Integration](/en/openapi/dataset): Create collections via API, push content to training queues asynchronously, and run search tests.

## Plugin System

* [Plugin development](/en/plugin/intro): Explore plugin types and development paths, start with [your first tool](/en/plugin/quick-start), and continue to [debugging and publishing](/en/plugin/debugging-and-publishing).
* [System Tool Development](/en/plugin/system-tool-development): Build single tools (`defineTool`) and tool suites (`defineToolSet`) with `@fastgpt-plugin/cli`.
* [Model Presets](/en/plugin/model-presets): Register new model providers and map AIProxy channels.
* [Package and SDK Reference](/en/plugin/package-reference): Inspect plugin directory conventions, package archive formats, and SDK type definitions.
* [Skill Development Tutorial](/en/guide/build/skill/development): Author custom Skills in the sandbox and bind them to an Agent.

## Machine-Readable OpenAPI Contracts

Each FastGPT deployment generates OpenAPI 3.1 specification files locally:

* **System OpenAPI (API Key Operations)**: Access `/apidoc/systemopenapi` (UI) or `/api/apidoc/systemopenapi.json` (JSON).
* **Dev API (Full Developer Operations)**: Access `/apidoc/devapi` (UI) or `/api/apidoc/devapi.json` (JSON).

When maintaining older integrations, refer to [Historical API Parameters and Migration](/en/openapi/legacy).