Log Compare: what changed between two logs
Give it a good run and a bad run of the same application, and optionally a third run. It shows the messages that are new, missing or changed, with how often each happened in every run. Files never leave your device.
Comparing…
Each bar is the count of a message in one run, drawn to the same scale. The small chart shows when in the run it happened, from start to end. Ranked by how far each count is from what the good run predicts for the bad run's size. Numbers, ids, IP addresses and quoted text are treated as the same message, so order 4411 and order 9020 count together. Stack trace lines are kept with their error and not counted again.
Questions about comparing logs
How do I compare two log files?
Drop the good run in the first box and the bad run in the second. The comparison runs as soon as both are loaded. Each message is counted in each run, and the messages that are new, missing or changed in the bad run are listed, largest difference first.
Why are numbers and ids treated as the same message?
Logs repeat the same message with different values: order 4411 and order 9020, or a different IP address each time. Those count as one message, so the list shows the kinds of messages that changed, not every value. The example line shows one real value.
Why are the counts scaled?
A longer run has more of everything. The good run is scaled to the size of the bad run before the two are compared, so a bad run that is simply longer is not reported as a set of problems. What is listed is a message that appears more or less often than the size of the run predicts.
Are stack traces counted as separate messages?
No. Lines that continue an error, such as "at ..." lines, "Caused by" and indented lines, are kept with their error and not counted again. The error line itself is counted once.
Does it work with logs from Docker, Kubernetes or a log tool?
Any plain text log whose lines hold the message is supported. Export the lines from your log tool as text first. Structured JSON logs and CSV exports are not read by this version.
Are my logs uploaded?
No. Both files are read by your browser, on your own device, and are not sent anywhere or saved. Closing the tab clears them.