Chaitanya Rai

Posted on Oct 23

Debugging Production: How to Fix Bugs Without Breaking Everything 🌐

#debugging #devops #production #developer

If you’ve ever pushed a bug to production (and who hasn’t?), you know that cold sweat moment when an error alert hits your Slack at 2 AM.

Debugging in production isn’t like fixing code on your laptop — there’s pressure, limited visibility, and real users depending on you. But with the right mindset and tools, you can handle it without breaking more things.

Let’s walk through a safe and strategic way to fix production issues — step by step.

🪵 1. Start by Reading the Logs — Carefully

Your logs are your first line of truth. Before touching the code or restarting anything, observe what’s actually happening.

✅ Tips:

Filter logs by request ID, timestamp, or user session.
Look for error patterns — repeating exceptions, failed API calls, or database connection errors.
Avoid drowning in noise: focus on recently changed modules.

🔍 Pro tip: Always include structured logs (JSON format, with timestamps, log levels, and trace IDs). It makes debugging 10x faster when your production system is busy.

🚩 2. Use Feature Flags to Limit the Blast Radius

When debugging a live app, never deploy experimental fixes directly.

This allows you to:

Turn features on or off instantly.
Roll out to a small % of users.
Roll back safely if something breaks.

Feature flags turn debugging from risky deployments into reversible switches.

⚙️ Example:

if (isFeatureEnabled('newCheckoutFlow')) {
    runNewCheckout();
} else {
    runOldCheckout();
}

🔄 3. Compare Versions — What Changed?

One of the smartest debugging habits: compare the current version with the last known good one.

You can:

Use git diff to check for recent code changes.
Match timestamps of new errors with deployment times.

🧠 80% of production bugs trace back to recent changes — even a single config tweak can ripple across your system.

🧪 4. Shadow Testing: Debug Without Impacting Real Users

Shadow testing (also called mirroring) is a lifesaver. It means sending a copy of real traffic to a test version of your app — without affecting actual users.

You can test new fixes safely and see how they behave under real-world conditions.

✅ Use it to:

Validate bug fixes.
Measure performance differences.
Detect unexpected side effects.

🧯 5. Safe Hotfix Deployment

Once you’ve confirmed the fix:

Deploy in stages.
Monitor metrics like response time, CPU, and error rates immediately.
If metrics spike — roll back instantly.

🧩 Always deploy hotfixes with the same process as regular releases

🧘 6. Stay Calm, Log Everything, Learn

Production debugging can feel chaotic, but post-incident learning turns chaos into improvement.

After you fix the bug:

Document what went wrong and how you found it.
Add new alerts or tests to catch similar issues earlier.
Share lessons in your team’s retro — no blame, just learning.

Debugging production isn’t about perfection — it’s about control under pressure.

🚀 Final Thoughts

Debugging production code is like defusing a bomb in slow motion — the key is precision, not panic.

If you:

Observe first (logs),
Contain impact (feature flags),
Verify (shadow testing),
Deploy safely (hotfix rollout),

…you’ll go from firefighting to fire prevention.

Remember: every production bug teaches you how to build systems that fail more gracefully next time.

💬 What’s your go-to strategy when something breaks in production? Share your tips below 👇

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