API Returning 500 Randomly (Async Bug You Might Be Ignoring)
Random 500 errors often come from unhandled async errors that silently crash your request flow.
Your API randomly returns 500 errors even though the code looks correct. It works sometimes, but fails unexpectedly under load or certain inputs.
Unhandled promise rejection inside async/await flow. When an awaited function throws an error and it's not wrapped in try/catch, Node.js fails the request and returns a generic 500 error.
Fix:
Always wrap async logic inside try/catch and handle promise rejections properly.
Bad:
app.get('/data', async (req, res) => {
const data = await fetchData(); // if this fails → 500
res.json(data);
});Good:
app.get('/data', async (req, res) => {
try {
const data = await fetchData();
res.json(data);
} catch (error) {
console.error('Error fetching data:', error);
res.status(500).json({ message: 'Internal Server Error' });
}
});Bonus Tip:
Also handle global unhandled rejections:
process.on('unhandledRejection', (err) => {
console.error('Unhandled Rejection:', err);
});More Bug of the Days
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