Log File Analyzer
Read large log files: filter by level, text, time and field, group repeated errors, merge files by time and share a redacted issue report.
Drop log files
Plain, JSON Lines, logfmt, syslog, web server, logcat and Kubernetes logs. Add several to compare or merge them by time.
No log at hand? .
About this tool
Open application logs, JSON Lines, logfmt, syslog, web server access logs, Android logcat or Kubernetes klog output. The format is detected from the first lines and shown with a preview of how they were read, and you can choose another for any file. Stack traces and other multi-line messages stay together as one event, and lines that don’t fit the format are kept, exactly as written, and marked.
Filter by level, text or a regular expression, time range, file and any field the log carries, such as host, thread or process. Repeated messages are grouped with numbers, ids and addresses set aside, bursts can collapse into one row, and every group opens to its original events. Bookmark events, read them in context and see the counts over time on a timeline you can select from.
Times keep the text they were written with. Times without a zone are read in the zone you choose, and times without a year, as classic syslog writes them, are never guessed: they stay off the timeline until you give the year. Several files merge by time only when their times can be compared. Save the matching events as written or as CSV, the repeated messages with counts, or an issue report with personal data and secrets replaced, which you read before it’s saved.
How large a log can it open?
Files are read in pieces and parsed in a background worker, so the page stays responsive. Up to a million events are held at once across all files; a longer log is read up to that point and says so.
Is anything uploaded or kept?
No. Logs are read on this device and forgotten when you close the page. Saved filters keep only levels, the search and view options, never log lines, field values or times.
Is the issue report safe to share?
It replaces email addresses, IP addresses, tokens, keys, card numbers and similar data it can recognise, and shows you the result first. It can’t recognise everything, such as names or internal hostnames, so read it before you share it, or review it in the Text Redactor.