Kotej
Compare two logs and find what actually changed
Two runs of the same service never produce the same log: every line has a different timestamp, PID or request ID. Kotej recognises the log format, sets those fields aside and compares the rest, so the one line that differs stands out.
Free, no account, and nothing is uploaded: everything is compared in your browser.
What it does
- Recognised by contentNo need for a .log extension: Spring Boot, log4j, JBoss, Python, klog, CRI, syslog, access logs, Serilog, JSON lines and logfmt are detected from the text.
- Volatile fields ignoredTimestamps, PIDs, thread IDs and request IDs are left out of the comparison by default. Choose which fields count.
- Fields in colourEach field is coloured so the level, the logger and the message are easy to tell apart, and ignored fields fade out.
- Your own formatFor a format Kotej doesn't know, describe it with a regular expression with named groups.
How to use it
- Open Kotej and pick the two logs: two restarts, two pods, before and after a deploy.
- Kotej detects the format and compares the lines that matter.
- Adjust which fields are compared, or mask IDs and numbers in the messages.
Questions
Can I compare logs from two Kubernetes pods?
Yes. Save both with kubectl logs and compare them: the pod-specific fields are ignored, so you see the lines one pod logged and the other didn't.
What if the messages contain IDs or numbers?
Turn on masking for IDs and numbers in the message, or add your own patterns, and those parts stop counting as differences.
Are multi-line entries like stack traces handled?
Yes. Continuation lines belong to the entry above them, so a stack trace is compared as part of its log entry.
Are my files uploaded?
No. Kotej runs entirely in your browser: files are read on your device and compared there. Nothing is sent to a server, which is also why it works on confidential configuration, customer data and production logs.
Is it free?
Yes, free and with no account. There is also a native macOS app with the same engine, for comparing folders straight from Finder: Kotej on the Mac App Store.