This Firebase Storage error occurs when the file checksum calculated on the client does not match the checksum validated by the server during upload. This indicates data corruption during transmission, typically caused by network interruptions or unstable connections. The solution is to retry the upload with proper error handling.
The "storage/invalid-checksum" error in Firebase Storage is a data integrity validation failure. Firebase Storage uses checksums (cryptographic hash values like MD5) to verify that the file received on the server exactly matches the file sent from the client. When you upload a file to Firebase Storage, the client SDK calculates a checksum of the file content before transmission. After the server receives the file, it recalculates the checksum independently and compares it with the client-provided value. If these values don't match, it indicates the file was corrupted or modified during transmission, and Firebase rejects the upload to prevent storing corrupted data. This error is a protective mechanism that ensures data integrity and prevents corrupted files from being silently stored, which could cause failures when attempting to download or use those files later.
Add automatic retry for failed uploads since checksum errors are often transient network issues:
// Web SDK example with retry logic
import { ref, uploadBytes } from 'firebase/storage';
async function uploadWithRetry(storage, filePath, file, maxRetries = 3) {
let lastError;
for (let attempt = 1; attempt <= maxRetries; attempt++) {
try {
const storageRef = ref(storage, filePath);
const result = await uploadBytes(storageRef, file);
console.log('Upload successful on attempt', attempt);
return result;
} catch (error) {
lastError = error;
if (error.code === 'storage/invalid-checksum') {
console.log(`Checksum error on attempt ${attempt}/${maxRetries}`);
if (attempt < maxRetries) {
// Exponential backoff: 1s, 2s, 4s
const delay = Math.pow(2, attempt - 1) * 1000;
console.log(`Retrying in ${delay}ms...`);
await new Promise(resolve => setTimeout(resolve, delay));
}
} else {
// Non-checksum error, don't retry
throw error;
}
}
}
throw lastError;
}
// Usage
try {
await uploadWithRetry(storage, 'uploads/myfile.pdf', fileBlob);
} catch (error) {
console.error('Upload failed after all retries:', error);
}This automatically handles transient network issues that cause most checksum errors.
Switch to resumable upload API for files over 5MB to handle interruptions gracefully:
// Web SDK - Resumable upload with pause/resume capability
import { ref, uploadBytesResumable } from 'firebase/storage';
function uploadLargeFile(storage, filePath, file) {
const storageRef = ref(storage, filePath);
const uploadTask = uploadBytesResumable(storageRef, file);
return new Promise((resolve, reject) => {
uploadTask.on('state_changed',
// Progress observer
(snapshot) => {
const progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
console.log('Upload is ' + progress + '% done');
switch (snapshot.state) {
case 'paused':
console.log('Upload is paused');
break;
case 'running':
console.log('Upload is running');
break;
}
},
// Error observer
(error) => {
if (error.code === 'storage/invalid-checksum') {
console.error('Checksum mismatch - retrying upload');
}
reject(error);
},
// Success observer
() => {
console.log('Upload completed successfully');
resolve(uploadTask.snapshot);
}
);
});
}
// Usage
try {
await uploadLargeFile(storage, 'uploads/large-file.mp4', videoFile);
} catch (error) {
console.error('Upload failed:', error);
}Resumable uploads handle network interruptions better than simple uploads.
Verify the file remains unchanged while uploading:
// Create immutable copy of file before upload
async function uploadImmutableFile(storage, filePath, file) {
// For File objects (from input), create a Blob copy
const immutableBlob = file.slice(0, file.size, file.type);
// Store original file size for verification
const originalSize = file.size;
const storageRef = ref(storage, filePath);
try {
const result = await uploadBytes(storageRef, immutableBlob);
return result;
} catch (error) {
if (error.code === 'storage/invalid-checksum') {
console.error('Checksum error - file may have been modified');
console.error('Original size:', originalSize);
console.error('Current size:', file.size);
}
throw error;
}
}
// For Node.js environment - read file once into buffer
const fs = require('fs');
const { getStorage, ref, uploadBytes } = require('firebase-admin/storage');
async function uploadFileFromDisk(filePath, storagePath) {
// Read entire file into memory at once (immutable)
const fileBuffer = fs.readFileSync(filePath);
const storage = getStorage();
const storageRef = ref(storage, storagePath);
// Upload from buffer (no concurrent modifications)
await uploadBytes(storageRef, fileBuffer);
}Using immutable copies prevents checksum mismatches from concurrent file modifications.
Upgrade to the latest Firebase SDK to fix checksum calculation bugs:
# For web projects
npm update firebase
# Check current version
npm list firebase
# Or update to specific latest version
npm install firebase@latest
# For React Native
npm update @react-native-firebase/storage
# For Flutter
flutter pub upgrade firebase_storageAfter updating, verify the SDK version:
// Check Firebase SDK version
import { SDK_VERSION } from 'firebase/app';
console.log('Firebase SDK version:', SDK_VERSION);
// For Admin SDK
const admin = require('firebase-admin');
console.log('Admin SDK version:', admin.SDK_VERSION);Recent versions include fixes for buffer handling on large files and checksum calculation issues.
Implement connection quality monitoring to pause/resume uploads:
// Monitor network status during upload
function monitorNetworkDuringUpload(uploadTask) {
// Check if online
if (!navigator.onLine) {
console.warn('Browser is offline');
uploadTask.pause();
return;
}
// Listen for network changes
window.addEventListener('online', () => {
console.log('Connection restored, resuming upload');
uploadTask.resume();
});
window.addEventListener('offline', () => {
console.log('Connection lost, pausing upload');
uploadTask.pause();
});
// Monitor connection quality
if ('connection' in navigator) {
const connection = navigator.connection;
console.log('Connection type:', connection.effectiveType);
connection.addEventListener('change', () => {
console.log('Connection changed to:', connection.effectiveType);
// Pause on slow connections
if (connection.effectiveType === 'slow-2g' || connection.effectiveType === '2g') {
console.warn('Slow connection detected, pausing upload');
uploadTask.pause();
}
});
}
}
// Usage with resumable upload
const uploadTask = uploadBytesResumable(storageRef, file);
monitorNetworkDuringUpload(uploadTask);This automatically handles network changes during upload.
### Understanding Checksum Validation
Firebase Storage uses MD5 checksums for upload validation:
- Client calculates MD5 hash of file content
- Hash is sent in Content-MD5 header (base64-encoded)
- Server recalculates MD5 and compares
- Mismatch triggers storage/invalid-checksum error
You can manually verify checksums:
// Calculate MD5 hash (Node.js)
const crypto = require('crypto');
const fs = require('fs');
function calculateMD5(filePath) {
return new Promise((resolve, reject) => {
const hash = crypto.createHash('md5');
const stream = fs.createReadStream(filePath);
stream.on('data', data => hash.update(data));
stream.on('end', () => resolve(hash.digest('base64')));
stream.on('error', reject);
});
}
// Compare local vs uploaded file
const localHash = await calculateMD5('/path/to/file.pdf');
console.log('Local MD5:', localHash);### Platform-Specific Issues
Android:
- Firebase Storage versions above 11.3.1 may have buffer size issues
- Files around 1GB may trigger out of memory errors
- Solution: Use latest version or downgrade to firebase_storage 11.3.1
iOS:
- Upload tasks may not resume properly after app backgrounding
- Solution: Manually implement state restoration and retry logic
Node.js:
- V8 engine buffer size limits (~2GB max for 64-bit systems)
- Cannot upload files larger than 2GB using uploadBytes()
- Solution: Use streaming APIs or split into multipart uploads
### Debugging Upload Failures
Enable detailed logging for upload diagnostics:
// Web SDK - monitor all state changes
uploadTask.on('state_changed',
(snapshot) => {
console.log({
state: snapshot.state,
bytesTransferred: snapshot.bytesTransferred,
totalBytes: snapshot.totalBytes,
metadata: snapshot.metadata
});
},
(error) => {
console.error('Upload error:', {
code: error.code,
message: error.message,
serverResponse: error.serverResponse
});
}
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