PromQL Query Explainer

How it works

The explainer never talks to a Prometheus server — it works entirely with regular expressions run against the text you paste: one pattern extracts the metric name, another pulls anything inside { } as label filters, another finds a [5m]-style range vector, and any recognized function name is looked up in a built-in glossary of about twenty functions and listed in the order it appears in the query.

FAQ

Does it check whether my PromQL query is actually valid?

No — it only recognizes patterns it knows how to explain; a query with a typo or broken syntax can still get partially explained, since the regexes just look for familiar shapes rather than parsing the query as Prometheus would.

Why didn't it explain one of the functions in my query?

Only functions in its built-in glossary — rate, sum, topk, histogram_quantile, and about twenty others — get a plain-English description; a valid but unlisted PromQL function is simply left out of the breakdown.