iOS Simulator (streamed panel)
macOS only. This extension does not run on Linux or Windows.
VS Code / Cursor extension that streams the iOS Simulator window into a webview via ScreenCaptureKit and sends taps with SimulatorKit Indigo HID (private SPI), so touches reach the booted simulator even when its window is behind other apps.
This is not true window embedding; it is a live JPEG stream plus host-side HID injection.
Source: github.com/mkloouo/vscode-ios-simulator-embed
Demo
Screen recording converted to GIF (first ~28s, 720px wide). Streamed panel with touch forwarding to a booted simulator.
Setup
Xcode (not only CLT): the helper links CoreSimulator and SimulatorKit from your active developer dir (xcode-select -p).
From the repo root:
npm install
npm run compile
npm run build:native
build:native runs native/ios-sim-helper/build.sh, which adds framework search paths and rpath so the binary finds those frameworks at runtime.
Open this folder in VS Code or Cursor, run Run Extension (F5).
Command Palette: iOS Simulator: Start streamed panel (stop with Stop streamed panel).
With multiple booted simulators, run iOS Simulator: Select booted simulator (UDID) so MAP, touches, and screenshots target one device.
Choosing the right window (stream) and device (touch)
Stream — windows are filtered by owning bundle ID (not title):
- iOS Simulator: List capture windows (debug) → Output “iOS Simulator Embed” (NDJSON, largest first).
- Set Target Bundle Id (
ios-simulator-embed.targetBundleId) or env IOS_SIM_HELPER_BUNDLE_ID.
Touch / MAP / screenshot device — targets a booted simulator via CoreSimulator and simctl:
- If only one simulator is booted, you can leave Simulator Udid empty.
- If several are booted, use iOS Simulator: Select booted simulator (UDID) (writes User setting
ios-simulator-embed.simulatorUdid) or set env IOS_SIM_UDID manually.
Coordinates — webview clicks are turned into normalized (0–1, top-left) positions over the streamed image. That matches Indigo’s ratio space for the device surface only approximately when the JPEG includes window chrome; adjust or crop later if needed.
macOS permissions
- Screen Recording: allow the app that hosts the Extension Host (Cursor / VS Code) for capture.
- Accessibility (Automation): not required for stream touches or ⌨ keyboard input (both use Indigo HID). Required for the panel toolbar shortcuts Home and Rotate (AppleScript / System Events). Screenshot uses
simctl only.
Keyboard — Tap the streamed image once (same as starting a touch); after that, keys are translated to USB HID usage codes and sent on the same touch sess Indigo pipe as drags/taps. Typing is disabled when the panel loses focus (click elsewhere, switch tabs, hide the webview). Turn off ios-simulator-embed.forwardSimulatorKeys to disable forwarding. Layout is US‑centric; some punctuation and IME composition are limited.
Chords (e.g. ⌃⌥Z, ⌃⌘Z) — The webview uses event.code (physical key) for modifier shortcuts because macOS often reports a non-printable or odd event.key. HID sends modifiers in ⌘ → Ctrl → Alt → Shift order and releases in reverse, which matters for multi-modifier shortcuts. If a chord still does nothing, Electron may still consume it (even with no VS Code binding): try another chord or file an issue with your host app version.
Spaces (Mission Control / virtual desktops)
ScreenCaptureKit only sees windows on the same Space as the app that runs the extension host (Cursor / VS Code). If the Simulator window is on another desktop, start the stream will not capture it until you move Simulator to the desktop where the editor is, then run Start streamed panel again.
After capture has started successfully, you can move Simulator to another Space; the stream, touches, and ⌨ keyboard (Indigo HID) usually keep working. The three toolbar buttons (Home, Screenshot, Rotate) may stop working in that situation: they rely on bringing the on-screen Simulator window to the front via AppleScript / simctl, which targets the Simulator instance on the current Space, not necessarily the one you are streaming.
Private API / stability
Touch uses undocumented Apple frameworks and wire formats; Xcode/Simulator updates can break this. See native/ios-sim-helper/THIRD_PARTY.md.
Limits
- Performance: ~12 FPS capture + coalesced webview updates; still CPU-heavy. Use setting streamJpegQuality to trade quality vs bandwidth.
- Packaging:
vscode:prepublish runs scripts/stage-native-helper.sh, which copies .build/release/ios-sim-helper into native/ios-sim-helper/dist/ (the VSIX includes dist and ignores SwiftPM .build). Run npm run build:native before packaging. npm run release -- patch (or minor / major, or an exact 1.2.3) requires a clean git tree: it bumps package.json, creates a chore(release): … commit and vX.Y.Z tag, then runs vsce package. Shorthand: npm run release:patch. Ship arm64 (and x86_64 if you build a universal binary) for your users’ Macs.
Native helper CLI
native/ios-sim-helper/.build/release/ios-sim-helper:
stream — stderr BOUNDS:…, stdout length-prefixed JPEG. Env IOS_SIM_HELPER_BUNDLE_ID optional.touch tap <nx> <ny> — Indigo tap; nx,ny in [0,1] from top-left of the simulated display. Env IOS_SIM_UDID optional.touch sess — stdin: d|m|u nx ny (touch) and kp|kd|ku <hidUsage> (USB HID keyboard page 0x07), one shared SimDeviceLegacyHIDClient.list — NDJSON of shareable macOS windows (debug bundle IDs for streaming).
Extension icon
The Visual Studio Marketplace expects a 128×128 PNG referenced by package.json as images/icon.png. The higher-resolution square source lives at images/icon-source.png (re-export with sips -z 128 128 images/icon-source.png --out images/icon.png after edits).
License
Copyright 2026 Mykola Odnosumov. Licensed under the Apache License 2.0 (see LICENSE). Portions of the native helper are derived from Meta idb (MIT); see native/ios-sim-helper/THIRD_PARTY.md.
