Besouro

On-device developer tools for React Native and Expo. Tap the floating bubble, get thirteen inspectors. No laptop, no remote debugger.

• Network: every request, with copy as cURL
• Console: logs, uncaught errors, and native crashes recovered on the next launch
• WebSocket and Socket.IO: messages and events in both directions
• Notifications: Expo, Firebase and Notifee, plus the device push token
• Redux, Zustand and Jotai: actions, live state, and what changed
• AsyncStorage and MMKV: every operation, and for MMKV the stored contents
• Element: tap any component to read and edit its props
• View Hierarchy: the native view tree as an exploded 3D stack
• Files: browse and share the app's sandbox

Requirements

• New Architecture only
• React Native 0.80+
• Expo SDK 54+, in a dev build (Expo Go can't load native code)

Installation

npm install besouro

It ships a native module, so rebuild:

# Expo
npx expo run:ios          # or run:android

# Bare React Native
cd ios && pod install
npx react-native run-ios  # or run-android

Quick start

// src/besouro.ts
import { Besouro } from 'besouro';

Besouro.init();

// index.js, before your app code
if (__DEV__) {
  require('./src/besouro');
}

Import it as early as possible. Anything that runs first is not captured: a socket opened at module load, a fetch fired before the app renders.

Want to enable Besouro in QA or release builds? See Shipping a release build with Besouro.

Enabled by default

Network

Console

WebSocket

Element

View Hierarchy

Files

State Management

Redux

// src/besouro.ts
import { Besouro } from 'besouro';
import { combineReducers, configureStore, createSlice } from '@reduxjs/toolkit';

const counterSlice = createSlice({
  name: 'counter',
  initialState: { value: 0 },
  reducers: {
    increment: (state) => {
      state.value += 1;
    },
  },
});

export const rootReducer = combineReducers({ counter: counterSlice.reducer });
export const store = configureStore({ reducer: rootReducer });

Besouro.redux(store, rootReducer).init();

Pass the root reducer too, or createAsyncThunk and RTK Query actions never show up. One store per app.

Zustand

// src/besouro.ts
import { Besouro } from 'besouro';
import { create } from 'zustand';

export const useCounterStore = create<{ count: number }>(() => ({ count: 0 }));

Besouro.zustand({ counter: useCounterStore }).init();

The key becomes the store's name in Besouro, counter here.

Jotai

// src/besouro.ts
import { Besouro } from 'besouro';
import { atom, getDefaultStore } from 'jotai';

export const countAtom = atom(0);
export const stepAtom = atom(1);

Besouro.jotai(getDefaultStore(), {
  count: countAtom,
  step: stepAtom,
}).init();

Only the atoms you name are captured.

Storage

AsyncStorage

// src/besouro.ts
import { Besouro } from 'besouro';
import AsyncStorage from '@react-native-async-storage/async-storage';

Besouro.asyncStorage(AsyncStorage).init();

MMKV

Requires react-native-mmkv v4.

// src/besouro.ts
import { Besouro } from 'besouro';
import { createMMKV } from 'react-native-mmkv';

export const storage = createMMKV();
export const settings = createMMKV({ id: 'settings' });

Besouro.mmkv({ default: storage, settings }).init();

Socket.IO

// src/besouro.ts
import { Besouro } from 'besouro';
import { Manager } from 'socket.io-client';

Besouro.socketIO(Manager).init();

Notifications

// src/besouro.ts
import { Besouro } from 'besouro';
import * as Notifications from 'expo-notifications';
import messaging from '@react-native-firebase/messaging';
import notifee from '@notifee/react-native';

Besouro.notifications({
  expoNotifications: Notifications,
  firebaseMessaging: messaging,
  notifee,
}).init();

Full example

// src/besouro.ts
import { Besouro } from 'besouro';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { Manager } from 'socket.io-client';
import { getDefaultStore } from 'jotai';
import notifee from '@notifee/react-native';

import { store, rootReducer } from './app/store';
import { useCartStore } from './stores/cart';
import { cartAtom, userAtom } from './state/atoms';
import { storage, settings } from './stores/mmkv';

Besouro.configure({ accent: '#7c3aed' })
  .redux(store, rootReducer)
  .zustand({ cart: useCartStore })
  .jotai(getDefaultStore(), { cart: cartAtom, user: userAtom })
  .asyncStorage(AsyncStorage)
  .mmkv({ default: storage, settings })
  .socketIO(Manager)
  .notifications({ notifee })
  .init();

Options

// src/besouro.ts
import { Besouro } from 'besouro';

Besouro.configure({
  maxSessions: 30,
  theme: 'dark',
  accent: '#7c3aed',
  locale: 'pt',
  inspectors: { fileSystem: false },
}).init();

Option	Default	Notes
maxSessions	10	Sessions kept on disk; older ones pruned at launch
theme	'system'	'system' | 'light' | 'dark'
accent	theme's own	'#rrggbb'
locale	'system'	'system' | 'en' | 'pt' | 'es'
inspectors	all on	Switch off network, console, websocket, element, viewHierarchy or fileSystem

Session history

Every launch is a session, kept on disk. Reopen a previous one; a run that ended in a crash is marked Crashed.

Native crashes

A crash that takes the whole process down (a Kotlin/Java exception, a Swift fatalError, a SIGSEGV) shows up in Console on the next launch, under the session that died.

Settings

Theme, accent, text size, language (English, Portuguese, Spanish) and tab order, changeable at any time.

Shipping a release build with Besouro

Sometimes you need Besouro in a release-mode build: a QA flavor, an internal beta, a release candidate you're chasing a bug in. Keep the config in one file and require it behind a flag that build sets, so your store release still drops it.

// index.js: the require is the switch
if (__DEV__ || process.env.EXPO_PUBLIC_BESOURO === '1') {
  require('./src/besouro');
}

The flag has to be build-time, not runtime: an env var your bundler inlines, or a constant a build script swaps. A runtime check keeps the library in every bundle.

Security

Everything captured is stored raw in the app's sandbox: request and response bodies, headers, tokens, cookies, whatever the app logged. Session history keeps it across launches. Fine on your own device; treat any build that ships Besouro as internal only, and don't hand one to anyone you wouldn't hand the data to.

Contributing

• Development workflow
• Sending a pull request
• Code of conduct

License

Apache-2.0 — see LICENSE.

---

Made with create-react-native-library