Log Comparison Report Generator

The question after any deploy or reprocessing is the same: what changed in the logs? Log Comparison Report Generator takes a before window and an after window and answers structurally — lines added, lines removed, and what stayed the same.

Underneath it compares the signals that matter: which client IPs appeared or vanished, how the HTTP status histogram moved, whether error volume rose or fell, and how log levels shifted. The result is a tight before/after summary ready for review boards and postmortems.

• Before/after diff — added, removed, common lines.
• IP movement — new and departed sources.
• Status drift — bucket deltas, top codes.
• Error delta — failure volume before vs after.
• Level shift — severity mix compared.
• Plain-text report — paste-ready.

1. Paste the before window (left).
2. Paste the after window (right).
3. Compare. The report renders instantly.
4. Copy the before/after summary.

Example 1 — Deploy review. Error delta zero but a new IP appeared — traffic source changed, behavior didn’t.

Example 2 — Reprocessing proof. Added/removed line counts match the expected reparse, and the status histogram drifted as intended.

Example 3 — Rate-limit test. 429 volume rising after the change is caught by both the code bucket and error sections.

• Change-focused — what actually moved.
• Signal aware — IPs, statuses, errors, levels.
• Multiset-correct — duplicates handled.
• Review-ready — plain-text output.
• Private — all processing client-side.