Vitejs Devtools Devtools

Vite DevTools Kit

@vitejs/devtools-kit is the hub that unites many devtools integrations. It owns the cross-tool surface — docking, the command palette, terminal aggregation, cross-tool toasts — and wraps the framework-neutral Devframe container with the Vite-specific glue (Plugin.devtools.setup).

If you have a portable Devframe app already, drop it in via createPluginFromDevframe(d) from @vitejs/devtools-kit/node and the kit auto-derives the iframe dock entry. If you're authoring a Vite-specific integration that needs hub features directly, reach for Plugin.devtools.setup.

Core Concepts

A DevTools plugin extends a Vite plugin with a devtools.setup(ctx) hook. The context is the kit-augmented context (KitNodeContext extended with Vite-specific fields) — it carries Devframe's portable surface plus the hub-only subsystems the kit owns:

Quick Start: Bridge a Devframe App

If you already have a portable Devframe definition, this is the one-liner. The kit synthesises the iframe dock entry from the definition's id / name / icon / basePath, mounts the SPA via views.hostStatic, runs the devtool's own setup, then runs the optional kit-only options.setup.

// vite.config.ts
import { createPluginFromDevframe } from '@vitejs/devtools-kit/node'
import devtool from './my-devtool'

export default {
  plugins: [
    createPluginFromDevframe(devtool, {
      // Optional kit-only setup for hub features:
      setup(ctx) {
        ctx.commands.register({
          id: 'my-devtool:clear-cache',
          title: 'Clear Cache',
          handler: () => {/* ... */},
        })
      },
    }),
  ],
}

Quick Start: Minimal Hub-Native Plugin

When the integration is intrinsically tied to Vite (it inspects the resolved config, augments middleware, etc.), reach for Plugin.devtools.setup directly:

/// <reference types="@vitejs/devtools-kit" />
import type { Plugin } from 'vite'

export default function myPlugin(): Plugin {
  return {
    name: 'my-plugin',
    devtools: {
      setup(ctx) {
        ctx.docks.register({
          id: 'my-plugin',
          title: 'My Plugin',
          icon: 'ph:puzzle-piece-duotone',
          type: 'iframe',
          url: 'https://example.com/devtools',
        })
      },
    },
  }
}

Quick Start: Full Integration

/// <reference types="@vitejs/devtools-kit" />
import type { Plugin } from 'vite'
import { fileURLToPath } from 'node:url'
import { defineRpcFunction } from '@vitejs/devtools-kit'

export default function myAnalyzer(): Plugin {
  const data = new Map<string, { size: number }>()

  return {
    name: 'my-analyzer',

    // Collect data in Vite hooks
    transform(code, id) {
      data.set(id, { size: code.length })
    },

    devtools: {
      setup(ctx) {
        // 1. Host static UI
        const clientPath = fileURLToPath(
          new URL('../dist/client', import.meta.url)
        )
        ctx.views.hostStatic('/__my-analyzer/', clientPath)

        // 2. Register dock entry
        ctx.docks.register({
          id: 'my-analyzer',
          title: 'Analyzer',
          icon: 'ph:chart-bar-duotone',
          type: 'iframe',
          url: '/__my-analyzer/',
        })

        // 3. Register RPC function
        ctx.rpc.register(
          defineRpcFunction({
            name: 'my-analyzer:get-data',
            type: 'query',
            setup: () => ({
              handler: async () => Array.from(data.entries()),
            }),
          })
        )
      },
    },
  }
}

Namespacing Convention

CRITICAL: Always prefix RPC functions, shared state keys, dock IDs, and command IDs with your plugin name:

// Good - namespaced
'my-plugin:get-modules'
'my-plugin:state'
'my-plugin:clear-cache'  // command ID

// Bad - may conflict
'get-modules'
'state'

Dock Entry Types

Iframe Entry

ctx.docks.register({
  id: 'my-plugin',
  title: 'My Plugin',
  icon: 'ph:house-duotone',
  type: 'iframe',
  url: '/__my-plugin/',
})

Iframes can also point at a remote-hosted URL that connects back via WebSocket, so you don't have to ship a SPA dist with your plugin:

ctx.docks.register({
  id: 'my-remote-tool',
  title: 'My Tool',
  icon: 'ph:cloud-duotone',
  type: 'iframe',
  url: 'https://example.com/devtools',
  remote: true, // or { transport: 'query', originLock: false }
})

On the hosted page, call connectRemoteDevTools() from @vitejs/devtools-kit/client to get a fully connected DevToolsRpcClient. Dev-mode only — auto-hidden in build mode. See Remote Client Patterns.

Action Entry

ctx.docks.register({
  id: 'my-inspector',
  title: 'Inspector',
  icon: 'ph:cursor-duotone',
  type: 'action',
  action: {
    importFrom: 'my-plugin/devtools-action',
    importName: 'default',
  },
})

Custom Render Entry

ctx.docks.register({
  id: 'my-custom',
  title: 'Custom View',
  icon: 'ph:code-duotone',
  type: 'custom-render',
  renderer: {
    importFrom: 'my-plugin/devtools-renderer',
    importName: 'default',
  },
})

JSON Render Entry

Build UIs entirely from server-side TypeScript — no client code needed:

const ui = ctx.createJsonRenderer({
  root: 'root',
  elements: {
    root: {
      type: 'Stack',
      props: { direction: 'vertical', gap: 12 },
      children: ['heading', 'info'],
    },
    heading: {
      type: 'Text',
      props: { content: 'Hello from JSON!', variant: 'heading' },
    },
    info: {
      type: 'KeyValueTable',
      props: {
        entries: [
          { key: 'Version', value: '1.0.0' },
          { key: 'Status', value: 'Running' },
        ],
      },
    },
  },
})

ctx.docks.register({
  id: 'my-panel',
  title: 'My Panel',
  icon: 'ph:chart-bar-duotone',
  type: 'json-render',
  ui,
})

Launcher Entry

const entry = ctx.docks.register({
  id: 'my-setup',
  title: 'My Setup',
  icon: 'ph:rocket-launch-duotone',
  type: 'launcher',
  launcher: {
    title: 'Initialize My Plugin',
    description: 'Run initial setup before using the plugin',
    buttonStart: 'Start Setup',
    buttonLoading: 'Setting up...',
    onLaunch: async () => {
      // Run initialization logic
    },
  },
})

Terminals & Subprocesses

Spawn and manage child processes with streaming terminal output:

const session = await ctx.terminals.startChildProcess(
  {
    command: 'vite',
    args: ['build', '--watch'],
    cwd: process.cwd(),
  },
  {
    id: 'my-plugin:build-watcher',
    title: 'Build Watcher',
    icon: 'ph:terminal-duotone',
  },
)

// Lifecycle controls
await session.terminate()
await session.restart()

A common pattern is combining with launcher docks — see Terminals Patterns.

Commands & Command Palette

Register executable commands discoverable via Mod+K palette:

import { defineCommand } from '@vitejs/devtools-kit'

ctx.commands.register(defineCommand({
  id: 'my-plugin:clear-cache',
  title: 'Clear Build Cache',
  icon: 'ph:trash-duotone',
  keybindings: [{ key: 'Mod+Shift+C' }],
  when: 'clientType == embedded',
  handler: async () => { /* ... */ },
}))

Commands support sub-commands (two-level hierarchy), conditional visibility via when clauses, and user-customizable keyboard shortcuts.

See Commands Patterns and When Clauses for full details.

Logs & Notifications

Plugins can emit structured log entries from both server and client contexts. Logs appear in the built-in Logs panel and can optionally show as toast notifications.

Fire-and-Forget

// No await needed
context.messages.add({
  message: 'Plugin initialized',
  level: 'info',
})

With Handle

const handle = await context.messages.add({
  id: 'my-build',
  message: 'Building...',
  level: 'info',
  status: 'loading',
})

// Update later
await handle.update({
  message: 'Build complete',
  level: 'success',
  status: 'idle',
})

// Or dismiss
await handle.dismiss()

Key Fields

The from field is automatically set to 'server' or 'browser'.

Deduplication

Re-adding with the same id updates the existing entry instead of creating a duplicate:

context.messages.add({ id: 'my-scan', message: 'Scanning...', level: 'info', status: 'loading' })
context.messages.add({ id: 'my-scan', message: 'Scan complete', level: 'success', status: 'idle' })

RPC Functions

Server-Side Definition

import { defineRpcFunction } from '@vitejs/devtools-kit'

const getModules = defineRpcFunction({
  name: 'my-plugin:get-modules',
  type: 'query', // 'query' | 'action' | 'static'
  setup: ctx => ({
    handler: async (filter?: string) => {
      // ctx has full ViteDevToolsNodeContext
      return modules.filter(m => !filter || m.includes(filter))
    },
  }),
})

// Register in setup
ctx.rpc.register(getModules)

Client-Side Call (iframe)

import { getDevToolsRpcClient } from '@vitejs/devtools-kit/client'

const rpc = await getDevToolsRpcClient()
const modules = await rpc.call('my-plugin:get-modules', 'src/')

Client-Side Call (action/renderer script)

import type { DevToolsClientScriptContext } from '@vitejs/devtools-kit/client'

export default function setup(ctx: DevToolsClientScriptContext) {
  ctx.current.events.on('entry:activated', async () => {
    const data = await ctx.current.rpc.call('my-plugin:get-data')
  })
}

Client Context

The global client context (DevToolsClientContext) provides access to the RPC client and is set automatically when DevTools initializes (embedded or standalone). Use getDevToolsClientContext() to access it from anywhere on the client side:

import { getDevToolsClientContext } from '@vitejs/devtools-kit/client'

const ctx = getDevToolsClientContext()
if (ctx) {
  const modules = await ctx.rpc.call('my-plugin:get-modules')
}

Broadcasting to Clients

// Server broadcasts to all clients
ctx.rpc.broadcast({
  method: 'my-plugin:on-update',
  args: [{ changedFile: '/src/main.ts' }],
})

Type Safety

Extend the DevTools Kit interfaces for full type checking:

// src/types.ts
import '@vitejs/devtools-kit'

declare module '@vitejs/devtools-kit' {
  interface DevToolsRpcServerFunctions {
    'my-plugin:get-modules': (filter?: string) => Promise<Module[]>
  }

  interface DevToolsRpcClientFunctions {
    'my-plugin:on-update': (data: { changedFile: string }) => void
  }

  interface DevToolsRpcSharedStates {
    'my-plugin:state': MyPluginState
  }
}

Shared State

Server-Side

const state = await ctx.rpc.sharedState.get('my-plugin:state', {
  initialValue: { count: 0, items: [] },
})

// Read
console.log(state.value())

// Mutate (auto-syncs to clients)
state.mutate((draft) => {
  draft.count += 1
  draft.items.push('new item')
})

Client-Side

const client = await getDevToolsRpcClient()
const state = await client.rpc.sharedState.get('my-plugin:state')

// Read
console.log(state.value())

// Subscribe to changes
state.on('updated', (newState) => {
  console.log('State updated:', newState)
})

Streaming Channels

For chunk-style data flowing in either direction (LLM deltas, build logs, file uploads), use a streaming channel rather than hand-rolling action + delta/end events. The same channel handles server→client and client→server.

Server-to-Client

ctx.rpc.streaming.create<string>('my-plugin:tokens', {
  replayWindow: 256, // chunks retained per stream id
})

// Inside an action handler:
const stream = channel.start()
;(async () => {
  for (const token of fakeLLM(prompt)) {
    if (stream.signal.aborted)
      return
    stream.write(token)
  }
  stream.close()
})()
return { streamId: stream.id }

// Client
import { getDevToolsRpcClient } from '@vitejs/devtools-kit/client'

const rpc = await getDevToolsRpcClient()
const { streamId } = await rpc.call('my-plugin:start', { prompt })
const reader = rpc.streaming.subscribe<string>('my-plugin:tokens', streamId)
for await (const token of reader)
  appendToken(token)
reader.cancel() // server stream.signal aborts

The reader is also .readable: ReadableStream<T> for pipeTo consumption. The sink is also .writable: WritableStream<T> — await channel.pipeFrom(readableSource) is the one-call shortcut.

Client-to-Server Uploads

// Server
ctx.rpc.register(defineRpcFunction({
  name: 'my-plugin:upload-file',
  type: 'action',
  handler: async ({ name }) => {
    const reader = channel.openInbound()
    ;(async () => {
      const file = createWriteStream(name)
      for await (const chunk of reader)
        file.write(chunk)
      file.close()
    })()
    return { uploadId: reader.id }
  },
}))

// Client
const { uploadId } = await rpc.call('my-plugin:upload-file', { name })
const upload = rpc.streaming.upload<Uint8Array>('my-plugin:files', uploadId)
fileReadable.pipeTo(upload.writable, { signal: upload.signal })

upload.signal aborts when the server calls reader.cancel(). Client disconnect surfaces as UploadDisconnected in the server's for await.

When to use streaming

For chat-style UIs, combine: keep the conversation log in shared state and stream active responses through the channel. Working example: devframe/examples/devframe-streaming-chat. Full reference: Streaming Patterns.

Client Scripts

For action buttons and custom renderers:

// src/devtools-action.ts
import type { DevToolsClientScriptContext } from '@vitejs/devtools-kit/client'

export default function setup(ctx: DevToolsClientScriptContext) {
  ctx.current.events.on('entry:activated', () => {
    console.log('Action activated')
    // Your inspector/tool logic here
  })

  ctx.current.events.on('entry:deactivated', () => {
    console.log('Action deactivated')
    // Cleanup
  })
}

Export from package.json:

{
  "exports": {
    ".": "./dist/index.mjs",
    "./devtools-action": "./dist/devtools-action.mjs"
  }
}

Debugging with Self-Inspect

Use @vitejs/devtools-self-inspect to debug your DevTools plugin. It shows registered RPC functions, dock entries, client scripts, and plugins in a meta-introspection UI at /__devtools-self-inspect/.

import DevTools from '@vitejs/devtools'
import DevToolsSelfInspect from '@vitejs/devtools-self-inspect'

export default defineConfig({
  plugins: [
    DevTools(),
    DevToolsSelfInspect(),
  ],
})

Best Practices

1. Always namespace - Prefix all identifiers with your plugin name
2. Use type augmentation - Extend DevToolsRpcServerFunctions for type-safe RPC
3. Keep state serializable - No functions or circular references in shared state
4. Batch mutations - Use single mutate() call for multiple changes
5. Host static files - Use ctx.views.hostStatic() for your UI assets
6. Use Iconify icons - Prefer ph:* (Phosphor) icons: icon: 'ph:chart-bar-duotone'
7. Deduplicate logs - Use explicit id for logs representing ongoing operations
8. Use Self-Inspect - Add @vitejs/devtools-self-inspect during development to debug your plugin
9. Namespace command IDs - Use my-plugin:action pattern for command IDs, same as RPC and state
10. Use when clauses - Conditionally show commands/docks with when expressions instead of programmatic show/hide

Example Plugins

Real-world example plugins in the repo — reference their code structure and patterns when building new integrations:

• A11y Checker (examples/plugin-a11y-checker) — Action dock entry, client-side axe-core audits, logs with severity levels and element positions, log handle updates
• File Explorer (examples/plugin-file-explorer) — Iframe dock entry, RPC functions (static/query/action), hosted UI panel, RPC dump for static builds, backend mode detection
• Git UI (examples/plugin-git-ui) — JSON render dock entry, server-side JSON specs, $bindState two-way binding, $state in action params, dynamic badge updates

Further Reading

• RPC Patterns - Advanced RPC patterns and type utilities
• Dock Entry Types - Detailed dock configuration options
• Shared State Patterns - Framework integration examples
• Streaming Patterns - Streaming channels, uploads, replay, chat-history pattern
• Project Structure - Recommended file organization
• JSON Render Patterns - Server-side JSON specs, components, state binding
• Terminals Patterns - Child processes, custom streams, session lifecycle
• Messages Patterns - Message entries, toast notifications, and handle patterns
• Diagnostics Patterns - Coded errors / warnings via ctx.diagnostics (nostics integration)
• Commands Patterns - Command registration, sub-commands, keybindings, palette integration
• When Clauses - Conditional expression syntax, context variables, API reference
• Remote Client Patterns - Remote-hosted iframe docks, connectRemoteDevTools, trust model
• Migration Guide - Breaking changes between versions

Source: vitejs/devtools — distributed by TomeVault.