Raycast Extension Development

Quick Start

1. Create project structure
2. Write package.json with extension config
3. Implement command in src/
4. Run npm install && npm run dev

Project Structure

my-extension/
├── package.json          # Extension manifest + dependencies
├── tsconfig.json         # TypeScript config
├── .eslintrc.json        # ESLint config
├── raycast-env.d.ts      # Type definitions (auto-generated)
├── assets/
│   └── extension-icon.png  # 512x512 PNG icon
└── src/
    └── command-name.tsx    # Command implementation

package.json Template

{
  "name": "extension-name",
  "title": "Extension Title",
  "description": "What this extension does",
  "icon": "extension-icon.png",
  "author": "author-name",
  "categories": ["Productivity", "Developer Tools"],
  "license": "MIT",
  "commands": [
    {
      "name": "command-name",
      "title": "Command Title",
      "description": "What this command does",
      "mode": "view",
      "keywords": ["keyword1", "keyword2"]
    }
  ],
  "dependencies": {
    "@raycast/api": "^1.83.1",
    "@raycast/utils": "^1.17.0"
  },
  "devDependencies": {
    "@raycast/eslint-config": "^1.0.11",
    "@types/node": "22.5.4",
    "@types/react": "18.3.3",
    "eslint": "^8.57.0",
    "prettier": "^3.3.3",
    "typescript": "^5.5.4"
  },
  "scripts": {
    "build": "ray build --skip-types -e dist -o dist",
    "dev": "ray develop",
    "fix-lint": "ray lint --fix",
    "lint": "ray lint"
  }
}

Command Modes

Mode	Use Case
view	Show UI with Detail, List, Form, Grid
no-view	Background task, clipboard, notifications only
menu-bar	Menu bar icon with dropdown

Hotkey Configuration

Add to command in package.json:

"hotkey": {
  "modifiers": ["opt"],
  "key": "m"
}

Modifiers: cmd, opt, ctrl, shift

Note: Hotkeys in package.json are suggestions. Users set them in Raycast Preferences → Extensions.

tsconfig.json

{
  "$schema": "https://json.schemastore.org/tsconfig",
  "compilerOptions": {
    "allowJs": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "isolatedModules": true,
    "jsx": "react-jsx",
    "lib": ["ES2022"],
    "module": "ES2022",
    "moduleResolution": "bundler",
    "noEmit": true,
    "resolveJsonModule": true,
    "skipLibCheck": true,
    "strict": true,
    "target": "ES2022"
  },
  "include": ["src/**/*", "raycast-env.d.ts"]
}

.eslintrc.json

{
  "root": true,
  "extends": ["@raycast"]
}

Command Patterns

No-View Command (Background Task)

import { showHUD, Clipboard, showToast, Toast } from "@raycast/api";

export default async function Command() {
  const toast = await showToast({
    style: Toast.Style.Animated,
    title: "Working...",
  });

  try {
    // Do work
    const result = await doSomething();

    await Clipboard.copy(result);
    await showHUD("✅ Done!");
  } catch (error) {
    toast.style = Toast.Style.Failure;
    toast.title = "Failed";
    toast.message = error instanceof Error ? error.message : "Unknown error";
  }
}

View Command (List)

import { List, ActionPanel, Action } from "@raycast/api";

export default function Command() {
  return (
    <List>
      <List.Item
        title="Item"
        actions={
          <ActionPanel>
            <Action.CopyToClipboard content="text" />
          </ActionPanel>
        }
      />
    </List>
  );
}

View Command (Detail)

import { Detail } from "@raycast/api";

export default function Command() {
  const markdown = `# Hello World`;
  return <Detail markdown={markdown} />;
}

Performance & Caching

Instant Load Pattern (No Empty Flash)

Use synchronous cache read + async refresh for instant perceived load:

import { List, Cache } from "@raycast/api";
import { useCachedPromise, withCache } from "@raycast/utils";

const cache = new Cache();
const CACHE_KEY = "myData";

// Read cache synchronously at module load (before React renders)
function getInitialData(): MyData[] {
  const cached = cache.get(CACHE_KEY);
  if (cached) {
    try {
      return JSON.parse(cached);
    } catch {
      return [];
    }
  }
  return [];
}

// Expensive async operation wrapped with withCache (5 min TTL)
const fetchExpensiveData = withCache(
  async () => {
    // Your expensive operation here
    return await someSlowOperation();
  },
  { maxAge: 5 * 60 * 1000 }
);

async function fetchAllData(): Promise<MyData[]> {
  const data = await fetchExpensiveData();
  // Update cache for next launch
  cache.set(CACHE_KEY, JSON.stringify(data));
  return data;
}

export default function Command() {
  const { data, isLoading } = useCachedPromise(fetchAllData, [], {
    initialData: getInitialData(), // Sync read - instant render!
    keepPreviousData: true,
  });

  return (
    <List isLoading={isLoading && !data?.length}>
      {data?.map(item => <List.Item key={item.id} title={item.name} />)}
    </List>
  );
}

Key Caching Utilities

Utility	Purpose
Cache	Persistent disk cache, sync read/write
withCache(fn, {maxAge})	Wrap async functions with TTL cache
useCachedPromise	Stale-while-revalidate pattern
LocalStorage	Async key-value storage

Avoiding CLS (Content Layout Shift)

Load all data in ONE async function:

// BAD - causes layout shift
const [customData, setCustomData] = useState([]);
useEffect(() => {
  loadCustomData().then(setCustomData); // Second render!
}, []);

// GOOD - single fetch, no shift
async function fetchAllData() {
  const [dataA, dataB] = await Promise.all([
    fetchDataA(),
    fetchDataB(),
  ]);
  return combineData(dataA, dataB);
}

Non-Blocking Operations (Prevent UI Freeze)

Root cause of "tiny delay": Sync operations (execSync, statSync, readdirSync) block the event loop during revalidation, freezing the UI even with cached data displayed.

// BAD - blocks event loop, UI freezes during revalidation
import { execSync } from "child_process";
import { statSync, readdirSync, copyFileSync } from "fs";

function fetchData() {
  copyFileSync(src, dest);                    // Blocks!
  const result = execSync("sqlite3 query");   // Blocks!
  const entries = readdirSync(dir);           // Blocks!
  for (const entry of entries) {
    statSync(join(dir, entry));               // Blocks N times!
  }
}

// GOOD - fully async, UI renders cached data while refreshing
import { exec } from "child_process";
import { promisify } from "util";
import { stat, readdir, copyFile, access } from "fs/promises";

const execAsync = promisify(exec);

async function fetchData() {
  await copyFile(src, dest);                         // Non-blocking
  const { stdout } = await execAsync("sqlite3...");  // Non-blocking

  // Use withFileTypes to avoid extra stat calls
  const entries = await readdir(dir, { withFileTypes: true });
  const results = entries
    .filter(e => e.isDirectory())  // No stat needed!
    .map(e => ({ path: join(dir, e.name), name: e.name }));
}

Key optimizations:

1. Replace execSync with promisify(exec) for shell commands
2. Replace existsSync with access() from fs/promises
3. Replace readdirSync + statSync loop with readdir(dir, { withFileTypes: true })
4. Run all path validations in parallel with Promise.all
5. Use SQLite URI mode for direct read-only access (no file copy needed)

SQLite Direct Access (Skip File Copy)

When reading SQLite databases from other apps (like Zed, VS Code, etc.), avoid copying the database file. Use URI mode for direct read-only access:

// BAD - copies entire database file (slow, blocks)
import { copyFileSync, unlinkSync } from "fs";

const tempDb = `/tmp/copy-${Date.now()}.sqlite`;
copyFileSync(originalDb, tempDb);           // Expensive!
execSync(`sqlite3 "${tempDb}" "SELECT..."`);
unlinkSync(tempDb);                         // Cleanup

// GOOD - direct read-only access via URI mode
const uri = `file:${originalDb}?mode=ro&immutable=1`;
const { stdout } = await execAsync(`sqlite3 "${uri}" "SELECT..."`);

URI parameters:

• mode=ro - Read-only mode, no write locks acquired
• immutable=1 - Skip WAL/lock checks, treat file as immutable

This eliminates the file copy entirely, saving significant I/O time.

execFile vs exec (Bypass Shell)

exec spawns a shell (20ms overhead), execFile calls binary directly (4ms):

// BAD - spawns shell, parses command string
import { exec } from "child_process";
const execAsync = promisify(exec);
await execAsync(`sqlite3 -separator '|||' "${db}" "${query}"`);

// GOOD - direct binary execution, ~16ms faster
import { execFile } from "child_process";
const execFileAsync = promisify(execFile);
await execFileAsync("sqlite3", ["-separator", "|||", db, query]);

Sidecar Pattern (True Background Preloading)

For truly instant cold starts, use a background worker to pre-warm the cache before the user opens the extension.

The Problem: view commands cannot use interval (background scheduling). Only no-view and menu-bar modes support it.

The Solution: Create two commands that share the same cache:

// package.json
{
  "commands": [
    {
      "name": "main",
      "title": "My Extension",
      "mode": "view"
    },
    {
      "name": "background-sync",
      "title": "Background Sync",
      "mode": "no-view",
      "interval": "15m"
    }
  ]
}

// shared-cache.ts - both commands import this
import { Cache } from "@raycast/api";
export const sharedCache = new Cache(); // Shared across extension

// background-sync.tsx (no-view worker)
import { sharedCache } from "./shared-cache";
export default async function Command() {
  const data = await fetchExpensiveData();
  sharedCache.set("projects", JSON.stringify(data));
}

// main.tsx (view command)
import { sharedCache } from "./shared-cache";
function getInitialData() {
  const cached = sharedCache.get("projects");
  return cached ? JSON.parse(cached) : [];
}
export default function Command() {
  const { data } = useCachedPromise(fetchData, [], {
    initialData: getInitialData(), // Instant from pre-warmed cache!
  });
}

Key points:

• Worker runs silently on interval, user never sees it
• Both commands share the same Cache (scoped to extension, not command)
• View command reads synchronously from pre-warmed cache
• Use 15m to 1h intervals to avoid battery/rate-limit issues

Large Datasets: useSQL over JSON Cache

For >1,000 items, use SQLite instead of JSON cache for instant filtering:

// BAD - loads entire 10MB JSON into memory to filter
const allProjects = JSON.parse(cache.get("projects"));
const filtered = allProjects.filter(p => p.name.includes(query));

// GOOD - SQLite queries only matching rows
import { useSQL } from "@raycast/utils";
const { data } = useSQL(dbPath, `SELECT * FROM projects WHERE name LIKE ?`, [`%${query}%`]);

Optimistic UI (Instant Actions)

For write operations, update UI immediately before API confirms:

const { mutate } = useCachedPromise(fetchItems);

async function deleteItem(id: string) {
  await mutate(deleteItemAPI(id), {
    optimisticUpdate: (current) => current.filter(i => i.id !== id),
    rollbackOnError: true, // Revert if API fails
  });
}

User sees instant feedback; rollback happens automatically on failure.

// BAD - sequential stat calls
const entries = readdirSync(dir);
for (const entry of entries) {
  const s = statSync(join(dir, entry));  // N blocking calls
}

// GOOD - parallel async checks
const checkPath = async (p: string) => {
  try {
    const s = await stat(p);
    return s.isDirectory() ? p : null;
  } catch { return null; }
};

const results = await Promise.all(paths.map(checkPath));

Common APIs

Clipboard

import { Clipboard } from "@raycast/api";

await Clipboard.copy("text");
await Clipboard.paste("text");
const text = await Clipboard.readText();

Notifications

import { showHUD, showToast, Toast } from "@raycast/api";

// Quick notification (disappears)
await showHUD("Done!");

// Toast with progress
const toast = await showToast({
  style: Toast.Style.Animated,
  title: "Loading...",
});
toast.style = Toast.Style.Success;
toast.title = "Complete";

AppleScript (macOS Integration)

import { runAppleScript } from "@raycast/utils";

// Get Chrome active tab URL
const url = await runAppleScript(`
  tell application "Google Chrome"
    return URL of active tab of front window
  end tell
`);

// Get Safari URL
const safariUrl = await runAppleScript(`
  tell application "Safari"
    return URL of current tab of front window
  end tell
`);

// Get frontmost app
const app = await runAppleScript(`
  tell application "System Events"
    return name of first application process whose frontmost is true
  end tell
`);

Fetch Data

// Native fetch works
const response = await fetch("https://api.example.com/data");
const data = await response.json();

Preferences

In package.json:

"preferences": [
  {
    "name": "apiKey",
    "type": "password",
    "required": true,
    "title": "API Key",
    "description": "Your API key"
  }
]

In code:

import { getPreferenceValues } from "@raycast/api";

interface Preferences {
  apiKey: string;
}

const { apiKey } = getPreferenceValues<Preferences>();

Creating Extension Icon

Use ImageMagick:

convert -size 512x512 xc:'#6366F1' -fill white -gravity center \
  -font Helvetica-Bold -pointsize 280 -annotate +0+20 'M' \
  assets/extension-icon.png

Development Workflow

# Install dependencies
npm install

# Start dev server (hot reload)
npm run dev

# Lint and fix
npm run fix-lint

# Build for production
npm run build

Raycast Deeplinks

Trigger Raycast commands programmatically via URL scheme:

# Reload all extensions
open "raycast://extensions/raycast/raycast/reload-extensions"

# Open Raycast
open "raycast://focus"

# Run any extension command
open "raycast://extensions/{author}/{extension}/{command}"

Auto-reload after build

Add to package.json scripts:

"build": "ray build --skip-types -e dist -o dist && open raycast://extensions/raycast/raycast/reload-extensions"

Or create a reload script:

#!/bin/bash
npm run build && open "raycast://extensions/raycast/raycast/reload-extensions"

Testing in Raycast

1. Run npm run dev (provides hot reload)
2. Open Raycast
3. Search for your command name
4. Press Enter to run

Without dev server running, use deeplink to reload after changes:

npm run build && open "raycast://extensions/raycast/raycast/reload-extensions"

Publishing

npm run publish

Submits to Raycast Store for review.