Log Analyzer

What this tool does

Paste a chunk of raw logs and this tool reads every line, works out the format, and gives you a one-screen summary instead of a wall of text. It runs entirely in your browser — nothing is uploaded, it works offline once the page has loaded, and there is no sign-up.

You get four things:

• Counts by level — every entry mapped to a unified severity (trace / debug / info / warn / error) with its share of the total.
• Top errors — the most frequent warning and error messages, ranked by count. Near-identical messages are grouped: numbers and long hex/UUID ids are masked, so db timeout attempt 3 and db timeout attempt 5 collapse into db timeout attempt # with a count of 2.
• Time span — the first and last timestamps found.
• Volume timeline — entries bucketed by minute, hour, or day (picked automatically from the span) with a little bar chart.

It auto-detects and analyzes five common shapes:

For access logs there is no level field, so severity comes from the HTTP status: 5xx → error, 4xx → warn, everything else → info. Any line the parser can't match is still counted (as an info-level entry) so the totals stay honest.

Want the row-by-row table, filtering, or CSV export instead of a summary? Use the sibling Log Parser tool — this one is the aggregate view.

Worked example

Paste these JSON logs with Format: Auto-detect:

{"ts":"2024-01-01T00:00:00Z","level":"info","msg":"server started"}
{"ts":"2024-01-01T00:20:00Z","level":"warn","msg":"high latency 900ms"}
{"ts":"2024-01-01T00:40:00Z","level":"error","msg":"db timeout attempt 3"}
{"ts":"2024-01-01T00:41:00Z","level":"error","msg":"db timeout attempt 5"}

The summary opens with a caption, breaks the four entries down by level, groups the two db timeout attempt N errors into one row, and buckets the volume per minute:

json · 4 entries · 2024-01-01 00:00:00 → 2024-01-01 00:41:00

## Levels

| level | count | share |
| --- | --- | --- |
| error | 2 | 50.0% |
| warn | 1 | 25.0% |
| info | 1 | 25.0% |

## Top errors

| count | level | message |
| --- | --- | --- |
| 2 | error | db timeout attempt # |
| 1 | warn | high latency #ms |

Switch Output as to JSON object for the same data as a structured object you can feed into a script.

FAQ