JSON is just a text file format, not a database. If two users try to write to the same JSON file at the same time, you can get:

• ❌ Corrupted JSON (half-written data)
• ❌ Lost updates (one write overwrites another)
• ❌ Race conditions
• ❌ Invalid file structure

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🔥 What Happens in Concurrent Writes?

Example:

User A writes:

{ "name": "Aditya" }

User B writes at the same time:

{ "email": "test@example.com" }

Result could become:

{ "name": "Adi{ "email": "test@example.com" }

Now the file is broken JSON.

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✅ How To Handle Concurrent Writes

1️⃣ File Locking (Basic Solution)

If you’re using PHP, use flock():

$file = 'data.json';
$fp = fopen($file, 'c+');if (flock($fp, LOCK_EX)) { // Exclusive lock
    $data = json_decode(file_get_contents($file), true);
    
    $data['new'] = 'value';
    
    ftruncate($fp, 0);
    rewind($fp);
    fwrite($fp, json_encode($data, JSON_PRETTY_PRINT));
    
    flock($fp, LOCK_UN);
}fclose($fp);

✔ Prevents two processes writing at same time
❌ Still not ideal for heavy traffic

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2️⃣ Write to Temp File + Rename (Safer Method)

Write to a temporary file and then replace:

file_put_contents('data_temp.json', json_encode($data));
rename('data_temp.json', 'data.json');

This reduces corruption risk.

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3️⃣ Use a Database (Best Solution 🚀)

If multiple users need to update data:

• MySQL
• PostgreSQL
• SQLite
• MongoDB

Databases are built for:

• Concurrency control
• Transactions
• Atomic writes
• Data integrity

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⚠️ When JSON is OK

Using JSON file is fine if:

• Single-user system
• Read-heavy, write-rare
• Static config file
• Low traffic site

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🚀 Enterprise Recommendation (For Your Projects)

Since you’re running SOA Technology and building scalable tools:

If:

• More than 5–10 concurrent users
• API-based system
• Production system

👉 Do NOT use JSON as primary storage
👉 Use MySQL / PostgreSQL

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🎯 Final Answer

Scenario	Safe?
Single user writing	✅ Yes
Multiple users writing	❌ No
Multiple users reading only	✅ Yes
High traffic system	❌ Use database